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Projet_SETI_RISC-V/riscv-gnu-toolchain/gcc/gcc/tree-ssa-loop-ivopts.cc
higepi 6c0debd407 projet
2023-03-06 14:48:14 +01:00

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/* Induction variable optimizations.
Copyright (C) 2003-2022 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
/* This pass tries to find the optimal set of induction variables for the loop.
It optimizes just the basic linear induction variables (although adding
support for other types should not be too hard). It includes the
optimizations commonly known as strength reduction, induction variable
coalescing and induction variable elimination. It does it in the
following steps:
1) The interesting uses of induction variables are found. This includes
-- uses of induction variables in non-linear expressions
-- addresses of arrays
-- comparisons of induction variables
Note the interesting uses are categorized and handled in group.
Generally, address type uses are grouped together if their iv bases
are different in constant offset.
2) Candidates for the induction variables are found. This includes
-- old induction variables
-- the variables defined by expressions derived from the "interesting
groups/uses" above
3) The optimal (w.r. to a cost function) set of variables is chosen. The
cost function assigns a cost to sets of induction variables and consists
of three parts:
-- The group/use costs. Each of the interesting groups/uses chooses
the best induction variable in the set and adds its cost to the sum.
The cost reflects the time spent on modifying the induction variables
value to be usable for the given purpose (adding base and offset for
arrays, etc.).
-- The variable costs. Each of the variables has a cost assigned that
reflects the costs associated with incrementing the value of the
variable. The original variables are somewhat preferred.
-- The set cost. Depending on the size of the set, extra cost may be
added to reflect register pressure.
All the costs are defined in a machine-specific way, using the target
hooks and machine descriptions to determine them.
4) The trees are transformed to use the new variables, the dead code is
removed.
All of this is done loop by loop. Doing it globally is theoretically
possible, it might give a better performance and it might enable us
to decide costs more precisely, but getting all the interactions right
would be complicated.
For the targets supporting low-overhead loops, IVOPTs has to take care of
the loops which will probably be transformed in RTL doloop optimization,
to try to make selected IV candidate set optimal. The process of doloop
support includes:
1) Analyze the current loop will be transformed to doloop or not, find and
mark its compare type IV use as doloop use (iv_group field doloop_p), and
set flag doloop_use_p of ivopts_data to notify subsequent processings on
doloop. See analyze_and_mark_doloop_use and its callees for the details.
The target hook predict_doloop_p can be used for target specific checks.
2) Add one doloop dedicated IV cand {(may_be_zero ? 1 : (niter + 1)), +, -1},
set flag doloop_p of iv_cand, step cost is set as zero and no extra cost
like biv. For cost determination between doloop IV cand and IV use, the
target hooks doloop_cost_for_generic and doloop_cost_for_address are
provided to add on extra costs for generic type and address type IV use.
Zero cost is assigned to the pair between doloop IV cand and doloop IV
use, and bound zero is set for IV elimination.
3) With the cost setting in step 2), the current cost model based IV
selection algorithm will process as usual, pick up doloop dedicated IV if
profitable. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "rtl.h"
#include "tree.h"
#include "gimple.h"
#include "cfghooks.h"
#include "tree-pass.h"
#include "memmodel.h"
#include "tm_p.h"
#include "ssa.h"
#include "expmed.h"
#include "insn-config.h"
#include "emit-rtl.h"
#include "recog.h"
#include "cgraph.h"
#include "gimple-pretty-print.h"
#include "alias.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "tree-eh.h"
#include "gimplify.h"
#include "gimple-iterator.h"
#include "gimplify-me.h"
#include "tree-cfg.h"
#include "tree-ssa-loop-ivopts.h"
#include "tree-ssa-loop-manip.h"
#include "tree-ssa-loop-niter.h"
#include "tree-ssa-loop.h"
#include "explow.h"
#include "expr.h"
#include "tree-dfa.h"
#include "tree-ssa.h"
#include "cfgloop.h"
#include "tree-scalar-evolution.h"
#include "tree-affine.h"
#include "tree-ssa-propagate.h"
#include "tree-ssa-address.h"
#include "builtins.h"
#include "tree-vectorizer.h"
#include "dbgcnt.h"
/* For lang_hooks.types.type_for_mode. */
#include "langhooks.h"
/* FIXME: Expressions are expanded to RTL in this pass to determine the
cost of different addressing modes. This should be moved to a TBD
interface between the GIMPLE and RTL worlds. */
/* The infinite cost. */
#define INFTY 1000000000
/* Returns the expected number of loop iterations for LOOP.
The average trip count is computed from profile data if it
exists. */
static inline HOST_WIDE_INT
avg_loop_niter (class loop *loop)
{
HOST_WIDE_INT niter = estimated_stmt_executions_int (loop);
if (niter == -1)
{
niter = likely_max_stmt_executions_int (loop);
if (niter == -1 || niter > param_avg_loop_niter)
return param_avg_loop_niter;
}
return niter;
}
struct iv_use;
/* Representation of the induction variable. */
struct iv
{
tree base; /* Initial value of the iv. */
tree base_object; /* A memory object to that the induction variable points. */
tree step; /* Step of the iv (constant only). */
tree ssa_name; /* The ssa name with the value. */
struct iv_use *nonlin_use; /* The identifier in the use if it is the case. */
bool biv_p; /* Is it a biv? */
bool no_overflow; /* True if the iv doesn't overflow. */
bool have_address_use;/* For biv, indicate if it's used in any address
type use. */
};
/* Per-ssa version information (induction variable descriptions, etc.). */
struct version_info
{
tree name; /* The ssa name. */
struct iv *iv; /* Induction variable description. */
bool has_nonlin_use; /* For a loop-level invariant, whether it is used in
an expression that is not an induction variable. */
bool preserve_biv; /* For the original biv, whether to preserve it. */
unsigned inv_id; /* Id of an invariant. */
};
/* Types of uses. */
enum use_type
{
USE_NONLINEAR_EXPR, /* Use in a nonlinear expression. */
USE_REF_ADDRESS, /* Use is an address for an explicit memory
reference. */
USE_PTR_ADDRESS, /* Use is a pointer argument to a function in
cases where the expansion of the function
will turn the argument into a normal address. */
USE_COMPARE /* Use is a compare. */
};
/* Cost of a computation. */
class comp_cost
{
public:
comp_cost (): cost (0), complexity (0), scratch (0)
{}
comp_cost (int64_t cost, unsigned complexity, int64_t scratch = 0)
: cost (cost), complexity (complexity), scratch (scratch)
{}
/* Returns true if COST is infinite. */
bool infinite_cost_p ();
/* Adds costs COST1 and COST2. */
friend comp_cost operator+ (comp_cost cost1, comp_cost cost2);
/* Adds COST to the comp_cost. */
comp_cost operator+= (comp_cost cost);
/* Adds constant C to this comp_cost. */
comp_cost operator+= (HOST_WIDE_INT c);
/* Subtracts constant C to this comp_cost. */
comp_cost operator-= (HOST_WIDE_INT c);
/* Divide the comp_cost by constant C. */
comp_cost operator/= (HOST_WIDE_INT c);
/* Multiply the comp_cost by constant C. */
comp_cost operator*= (HOST_WIDE_INT c);
/* Subtracts costs COST1 and COST2. */
friend comp_cost operator- (comp_cost cost1, comp_cost cost2);
/* Subtracts COST from this comp_cost. */
comp_cost operator-= (comp_cost cost);
/* Returns true if COST1 is smaller than COST2. */
friend bool operator< (comp_cost cost1, comp_cost cost2);
/* Returns true if COST1 and COST2 are equal. */
friend bool operator== (comp_cost cost1, comp_cost cost2);
/* Returns true if COST1 is smaller or equal than COST2. */
friend bool operator<= (comp_cost cost1, comp_cost cost2);
int64_t cost; /* The runtime cost. */
unsigned complexity; /* The estimate of the complexity of the code for
the computation (in no concrete units --
complexity field should be larger for more
complex expressions and addressing modes). */
int64_t scratch; /* Scratch used during cost computation. */
};
static const comp_cost no_cost;
static const comp_cost infinite_cost (INFTY, 0, INFTY);
bool
comp_cost::infinite_cost_p ()
{
return cost == INFTY;
}
comp_cost
operator+ (comp_cost cost1, comp_cost cost2)
{
if (cost1.infinite_cost_p () || cost2.infinite_cost_p ())
return infinite_cost;
gcc_assert (cost1.cost + cost2.cost < infinite_cost.cost);
cost1.cost += cost2.cost;
cost1.complexity += cost2.complexity;
return cost1;
}
comp_cost
operator- (comp_cost cost1, comp_cost cost2)
{
if (cost1.infinite_cost_p ())
return infinite_cost;
gcc_assert (!cost2.infinite_cost_p ());
gcc_assert (cost1.cost - cost2.cost < infinite_cost.cost);
cost1.cost -= cost2.cost;
cost1.complexity -= cost2.complexity;
return cost1;
}
comp_cost
comp_cost::operator+= (comp_cost cost)
{
*this = *this + cost;
return *this;
}
comp_cost
comp_cost::operator+= (HOST_WIDE_INT c)
{
if (c >= INFTY)
this->cost = INFTY;
if (infinite_cost_p ())
return *this;
gcc_assert (this->cost + c < infinite_cost.cost);
this->cost += c;
return *this;
}
comp_cost
comp_cost::operator-= (HOST_WIDE_INT c)
{
if (infinite_cost_p ())
return *this;
gcc_assert (this->cost - c < infinite_cost.cost);
this->cost -= c;
return *this;
}
comp_cost
comp_cost::operator/= (HOST_WIDE_INT c)
{
gcc_assert (c != 0);
if (infinite_cost_p ())
return *this;
this->cost /= c;
return *this;
}
comp_cost
comp_cost::operator*= (HOST_WIDE_INT c)
{
if (infinite_cost_p ())
return *this;
gcc_assert (this->cost * c < infinite_cost.cost);
this->cost *= c;
return *this;
}
comp_cost
comp_cost::operator-= (comp_cost cost)
{
*this = *this - cost;
return *this;
}
bool
operator< (comp_cost cost1, comp_cost cost2)
{
if (cost1.cost == cost2.cost)
return cost1.complexity < cost2.complexity;
return cost1.cost < cost2.cost;
}
bool
operator== (comp_cost cost1, comp_cost cost2)
{
return cost1.cost == cost2.cost
&& cost1.complexity == cost2.complexity;
}
bool
operator<= (comp_cost cost1, comp_cost cost2)
{
return cost1 < cost2 || cost1 == cost2;
}
struct iv_inv_expr_ent;
/* The candidate - cost pair. */
class cost_pair
{
public:
struct iv_cand *cand; /* The candidate. */
comp_cost cost; /* The cost. */
enum tree_code comp; /* For iv elimination, the comparison. */
bitmap inv_vars; /* The list of invariant ssa_vars that have to be
preserved when representing iv_use with iv_cand. */
bitmap inv_exprs; /* The list of newly created invariant expressions
when representing iv_use with iv_cand. */
tree value; /* For final value elimination, the expression for
the final value of the iv. For iv elimination,
the new bound to compare with. */
};
/* Use. */
struct iv_use
{
unsigned id; /* The id of the use. */
unsigned group_id; /* The group id the use belongs to. */
enum use_type type; /* Type of the use. */
tree mem_type; /* The memory type to use when testing whether an
address is legitimate, and what the address's
cost is. */
struct iv *iv; /* The induction variable it is based on. */
gimple *stmt; /* Statement in that it occurs. */
tree *op_p; /* The place where it occurs. */
tree addr_base; /* Base address with const offset stripped. */
poly_uint64_pod addr_offset;
/* Const offset stripped from base address. */
};
/* Group of uses. */
struct iv_group
{
/* The id of the group. */
unsigned id;
/* Uses of the group are of the same type. */
enum use_type type;
/* The set of "related" IV candidates, plus the important ones. */
bitmap related_cands;
/* Number of IV candidates in the cost_map. */
unsigned n_map_members;
/* The costs wrto the iv candidates. */
class cost_pair *cost_map;
/* The selected candidate for the group. */
struct iv_cand *selected;
/* To indicate this is a doloop use group. */
bool doloop_p;
/* Uses in the group. */
vec<struct iv_use *> vuses;
};
/* The position where the iv is computed. */
enum iv_position
{
IP_NORMAL, /* At the end, just before the exit condition. */
IP_END, /* At the end of the latch block. */
IP_BEFORE_USE, /* Immediately before a specific use. */
IP_AFTER_USE, /* Immediately after a specific use. */
IP_ORIGINAL /* The original biv. */
};
/* The induction variable candidate. */
struct iv_cand
{
unsigned id; /* The number of the candidate. */
bool important; /* Whether this is an "important" candidate, i.e. such
that it should be considered by all uses. */
bool involves_undefs; /* Whether the IV involves undefined values. */
ENUM_BITFIELD(iv_position) pos : 8; /* Where it is computed. */
gimple *incremented_at;/* For original biv, the statement where it is
incremented. */
tree var_before; /* The variable used for it before increment. */
tree var_after; /* The variable used for it after increment. */
struct iv *iv; /* The value of the candidate. NULL for
"pseudocandidate" used to indicate the possibility
to replace the final value of an iv by direct
computation of the value. */
unsigned cost; /* Cost of the candidate. */
unsigned cost_step; /* Cost of the candidate's increment operation. */
struct iv_use *ainc_use; /* For IP_{BEFORE,AFTER}_USE candidates, the place
where it is incremented. */
bitmap inv_vars; /* The list of invariant ssa_vars used in step of the
iv_cand. */
bitmap inv_exprs; /* If step is more complicated than a single ssa_var,
hanlde it as a new invariant expression which will
be hoisted out of loop. */
struct iv *orig_iv; /* The original iv if this cand is added from biv with
smaller type. */
bool doloop_p; /* Whether this is a doloop candidate. */
};
/* Hashtable entry for common candidate derived from iv uses. */
class iv_common_cand
{
public:
tree base;
tree step;
/* IV uses from which this common candidate is derived. */
auto_vec<struct iv_use *> uses;
hashval_t hash;
};
/* Hashtable helpers. */
struct iv_common_cand_hasher : delete_ptr_hash <iv_common_cand>
{
static inline hashval_t hash (const iv_common_cand *);
static inline bool equal (const iv_common_cand *, const iv_common_cand *);
};
/* Hash function for possible common candidates. */
inline hashval_t
iv_common_cand_hasher::hash (const iv_common_cand *ccand)
{
return ccand->hash;
}
/* Hash table equality function for common candidates. */
inline bool
iv_common_cand_hasher::equal (const iv_common_cand *ccand1,
const iv_common_cand *ccand2)
{
return (ccand1->hash == ccand2->hash
&& operand_equal_p (ccand1->base, ccand2->base, 0)
&& operand_equal_p (ccand1->step, ccand2->step, 0)
&& (TYPE_PRECISION (TREE_TYPE (ccand1->base))
== TYPE_PRECISION (TREE_TYPE (ccand2->base))));
}
/* Loop invariant expression hashtable entry. */
struct iv_inv_expr_ent
{
/* Tree expression of the entry. */
tree expr;
/* Unique indentifier. */
int id;
/* Hash value. */
hashval_t hash;
};
/* Sort iv_inv_expr_ent pair A and B by id field. */
static int
sort_iv_inv_expr_ent (const void *a, const void *b)
{
const iv_inv_expr_ent * const *e1 = (const iv_inv_expr_ent * const *) (a);
const iv_inv_expr_ent * const *e2 = (const iv_inv_expr_ent * const *) (b);
unsigned id1 = (*e1)->id;
unsigned id2 = (*e2)->id;
if (id1 < id2)
return -1;
else if (id1 > id2)
return 1;
else
return 0;
}
/* Hashtable helpers. */
struct iv_inv_expr_hasher : free_ptr_hash <iv_inv_expr_ent>
{
static inline hashval_t hash (const iv_inv_expr_ent *);
static inline bool equal (const iv_inv_expr_ent *, const iv_inv_expr_ent *);
};
/* Return true if uses of type TYPE represent some form of address. */
inline bool
address_p (use_type type)
{
return type == USE_REF_ADDRESS || type == USE_PTR_ADDRESS;
}
/* Hash function for loop invariant expressions. */
inline hashval_t
iv_inv_expr_hasher::hash (const iv_inv_expr_ent *expr)
{
return expr->hash;
}
/* Hash table equality function for expressions. */
inline bool
iv_inv_expr_hasher::equal (const iv_inv_expr_ent *expr1,
const iv_inv_expr_ent *expr2)
{
return expr1->hash == expr2->hash
&& operand_equal_p (expr1->expr, expr2->expr, 0);
}
struct ivopts_data
{
/* The currently optimized loop. */
class loop *current_loop;
location_t loop_loc;
/* Numbers of iterations for all exits of the current loop. */
hash_map<edge, tree_niter_desc *> *niters;
/* Number of registers used in it. */
unsigned regs_used;
/* The size of version_info array allocated. */
unsigned version_info_size;
/* The array of information for the ssa names. */
struct version_info *version_info;
/* The hashtable of loop invariant expressions created
by ivopt. */
hash_table<iv_inv_expr_hasher> *inv_expr_tab;
/* The bitmap of indices in version_info whose value was changed. */
bitmap relevant;
/* The uses of induction variables. */
vec<iv_group *> vgroups;
/* The candidates. */
vec<iv_cand *> vcands;
/* A bitmap of important candidates. */
bitmap important_candidates;
/* Cache used by tree_to_aff_combination_expand. */
hash_map<tree, name_expansion *> *name_expansion_cache;
/* The hashtable of common candidates derived from iv uses. */
hash_table<iv_common_cand_hasher> *iv_common_cand_tab;
/* The common candidates. */
vec<iv_common_cand *> iv_common_cands;
/* Hash map recording base object information of tree exp. */
hash_map<tree, tree> *base_object_map;
/* The maximum invariant variable id. */
unsigned max_inv_var_id;
/* The maximum invariant expression id. */
unsigned max_inv_expr_id;
/* Number of no_overflow BIVs which are not used in memory address. */
unsigned bivs_not_used_in_addr;
/* Obstack for iv structure. */
struct obstack iv_obstack;
/* Whether to consider just related and important candidates when replacing a
use. */
bool consider_all_candidates;
/* Are we optimizing for speed? */
bool speed;
/* Whether the loop body includes any function calls. */
bool body_includes_call;
/* Whether the loop body can only be exited via single exit. */
bool loop_single_exit_p;
/* Whether the loop has doloop comparison use. */
bool doloop_use_p;
};
/* An assignment of iv candidates to uses. */
class iv_ca
{
public:
/* The number of uses covered by the assignment. */
unsigned upto;
/* Number of uses that cannot be expressed by the candidates in the set. */
unsigned bad_groups;
/* Candidate assigned to a use, together with the related costs. */
class cost_pair **cand_for_group;
/* Number of times each candidate is used. */
unsigned *n_cand_uses;
/* The candidates used. */
bitmap cands;
/* The number of candidates in the set. */
unsigned n_cands;
/* The number of invariants needed, including both invariant variants and
invariant expressions. */
unsigned n_invs;
/* Total cost of expressing uses. */
comp_cost cand_use_cost;
/* Total cost of candidates. */
int64_t cand_cost;
/* Number of times each invariant variable is used. */
unsigned *n_inv_var_uses;
/* Number of times each invariant expression is used. */
unsigned *n_inv_expr_uses;
/* Total cost of the assignment. */
comp_cost cost;
};
/* Difference of two iv candidate assignments. */
struct iv_ca_delta
{
/* Changed group. */
struct iv_group *group;
/* An old assignment (for rollback purposes). */
class cost_pair *old_cp;
/* A new assignment. */
class cost_pair *new_cp;
/* Next change in the list. */
struct iv_ca_delta *next;
};
/* Bound on number of candidates below that all candidates are considered. */
#define CONSIDER_ALL_CANDIDATES_BOUND \
((unsigned) param_iv_consider_all_candidates_bound)
/* If there are more iv occurrences, we just give up (it is quite unlikely that
optimizing such a loop would help, and it would take ages). */
#define MAX_CONSIDERED_GROUPS \
((unsigned) param_iv_max_considered_uses)
/* If there are at most this number of ivs in the set, try removing unnecessary
ivs from the set always. */
#define ALWAYS_PRUNE_CAND_SET_BOUND \
((unsigned) param_iv_always_prune_cand_set_bound)
/* The list of trees for that the decl_rtl field must be reset is stored
here. */
static vec<tree> decl_rtl_to_reset;
static comp_cost force_expr_to_var_cost (tree, bool);
/* The single loop exit if it dominates the latch, NULL otherwise. */
edge
single_dom_exit (class loop *loop)
{
edge exit = single_exit (loop);
if (!exit)
return NULL;
if (!just_once_each_iteration_p (loop, exit->src))
return NULL;
return exit;
}
/* Dumps information about the induction variable IV to FILE. Don't dump
variable's name if DUMP_NAME is FALSE. The information is dumped with
preceding spaces indicated by INDENT_LEVEL. */
void
dump_iv (FILE *file, struct iv *iv, bool dump_name, unsigned indent_level)
{
const char *p;
const char spaces[9] = {' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', '\0'};
if (indent_level > 4)
indent_level = 4;
p = spaces + 8 - (indent_level << 1);
fprintf (file, "%sIV struct:\n", p);
if (iv->ssa_name && dump_name)
{
fprintf (file, "%s SSA_NAME:\t", p);
print_generic_expr (file, iv->ssa_name, TDF_SLIM);
fprintf (file, "\n");
}
fprintf (file, "%s Type:\t", p);
print_generic_expr (file, TREE_TYPE (iv->base), TDF_SLIM);
fprintf (file, "\n");
fprintf (file, "%s Base:\t", p);
print_generic_expr (file, iv->base, TDF_SLIM);
fprintf (file, "\n");
fprintf (file, "%s Step:\t", p);
print_generic_expr (file, iv->step, TDF_SLIM);
fprintf (file, "\n");
if (iv->base_object)
{
fprintf (file, "%s Object:\t", p);
print_generic_expr (file, iv->base_object, TDF_SLIM);
fprintf (file, "\n");
}
fprintf (file, "%s Biv:\t%c\n", p, iv->biv_p ? 'Y' : 'N');
fprintf (file, "%s Overflowness wrto loop niter:\t%s\n",
p, iv->no_overflow ? "No-overflow" : "Overflow");
}
/* Dumps information about the USE to FILE. */
void
dump_use (FILE *file, struct iv_use *use)
{
fprintf (file, " Use %d.%d:\n", use->group_id, use->id);
fprintf (file, " At stmt:\t");
print_gimple_stmt (file, use->stmt, 0);
fprintf (file, " At pos:\t");
if (use->op_p)
print_generic_expr (file, *use->op_p, TDF_SLIM);
fprintf (file, "\n");
dump_iv (file, use->iv, false, 2);
}
/* Dumps information about the uses to FILE. */
void
dump_groups (FILE *file, struct ivopts_data *data)
{
unsigned i, j;
struct iv_group *group;
for (i = 0; i < data->vgroups.length (); i++)
{
group = data->vgroups[i];
fprintf (file, "Group %d:\n", group->id);
if (group->type == USE_NONLINEAR_EXPR)
fprintf (file, " Type:\tGENERIC\n");
else if (group->type == USE_REF_ADDRESS)
fprintf (file, " Type:\tREFERENCE ADDRESS\n");
else if (group->type == USE_PTR_ADDRESS)
fprintf (file, " Type:\tPOINTER ARGUMENT ADDRESS\n");
else
{
gcc_assert (group->type == USE_COMPARE);
fprintf (file, " Type:\tCOMPARE\n");
}
for (j = 0; j < group->vuses.length (); j++)
dump_use (file, group->vuses[j]);
}
}
/* Dumps information about induction variable candidate CAND to FILE. */
void
dump_cand (FILE *file, struct iv_cand *cand)
{
struct iv *iv = cand->iv;
fprintf (file, "Candidate %d:\n", cand->id);
if (cand->inv_vars)
{
fprintf (file, " Depend on inv.vars: ");
dump_bitmap (file, cand->inv_vars);
}
if (cand->inv_exprs)
{
fprintf (file, " Depend on inv.exprs: ");
dump_bitmap (file, cand->inv_exprs);
}
if (cand->var_before)
{
fprintf (file, " Var befor: ");
print_generic_expr (file, cand->var_before, TDF_SLIM);
fprintf (file, "\n");
}
if (cand->var_after)
{
fprintf (file, " Var after: ");
print_generic_expr (file, cand->var_after, TDF_SLIM);
fprintf (file, "\n");
}
switch (cand->pos)
{
case IP_NORMAL:
fprintf (file, " Incr POS: before exit test\n");
break;
case IP_BEFORE_USE:
fprintf (file, " Incr POS: before use %d\n", cand->ainc_use->id);
break;
case IP_AFTER_USE:
fprintf (file, " Incr POS: after use %d\n", cand->ainc_use->id);
break;
case IP_END:
fprintf (file, " Incr POS: at end\n");
break;
case IP_ORIGINAL:
fprintf (file, " Incr POS: orig biv\n");
break;
}
dump_iv (file, iv, false, 1);
}
/* Returns the info for ssa version VER. */
static inline struct version_info *
ver_info (struct ivopts_data *data, unsigned ver)
{
return data->version_info + ver;
}
/* Returns the info for ssa name NAME. */
static inline struct version_info *
name_info (struct ivopts_data *data, tree name)
{
return ver_info (data, SSA_NAME_VERSION (name));
}
/* Returns true if STMT is after the place where the IP_NORMAL ivs will be
emitted in LOOP. */
static bool
stmt_after_ip_normal_pos (class loop *loop, gimple *stmt)
{
basic_block bb = ip_normal_pos (loop), sbb = gimple_bb (stmt);
gcc_assert (bb);
if (sbb == loop->latch)
return true;
if (sbb != bb)
return false;
return stmt == last_stmt (bb);
}
/* Returns true if STMT if after the place where the original induction
variable CAND is incremented. If TRUE_IF_EQUAL is set, we return true
if the positions are identical. */
static bool
stmt_after_inc_pos (struct iv_cand *cand, gimple *stmt, bool true_if_equal)
{
basic_block cand_bb = gimple_bb (cand->incremented_at);
basic_block stmt_bb = gimple_bb (stmt);
if (!dominated_by_p (CDI_DOMINATORS, stmt_bb, cand_bb))
return false;
if (stmt_bb != cand_bb)
return true;
if (true_if_equal
&& gimple_uid (stmt) == gimple_uid (cand->incremented_at))
return true;
return gimple_uid (stmt) > gimple_uid (cand->incremented_at);
}
/* Returns true if STMT if after the place where the induction variable
CAND is incremented in LOOP. */
static bool
stmt_after_increment (class loop *loop, struct iv_cand *cand, gimple *stmt)
{
switch (cand->pos)
{
case IP_END:
return false;
case IP_NORMAL:
return stmt_after_ip_normal_pos (loop, stmt);
case IP_ORIGINAL:
case IP_AFTER_USE:
return stmt_after_inc_pos (cand, stmt, false);
case IP_BEFORE_USE:
return stmt_after_inc_pos (cand, stmt, true);
default:
gcc_unreachable ();
}
}
/* walk_tree callback for contains_abnormal_ssa_name_p. */
static tree
contains_abnormal_ssa_name_p_1 (tree *tp, int *walk_subtrees, void *)
{
if (TREE_CODE (*tp) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (*tp))
return *tp;
if (!EXPR_P (*tp))
*walk_subtrees = 0;
return NULL_TREE;
}
/* Returns true if EXPR contains a ssa name that occurs in an
abnormal phi node. */
bool
contains_abnormal_ssa_name_p (tree expr)
{
return walk_tree_without_duplicates
(&expr, contains_abnormal_ssa_name_p_1, NULL) != NULL_TREE;
}
/* Returns the structure describing number of iterations determined from
EXIT of DATA->current_loop, or NULL if something goes wrong. */
static class tree_niter_desc *
niter_for_exit (struct ivopts_data *data, edge exit)
{
class tree_niter_desc *desc;
tree_niter_desc **slot;
if (!data->niters)
{
data->niters = new hash_map<edge, tree_niter_desc *>;
slot = NULL;
}
else
slot = data->niters->get (exit);
if (!slot)
{
/* Try to determine number of iterations. We cannot safely work with ssa
names that appear in phi nodes on abnormal edges, so that we do not
create overlapping life ranges for them (PR 27283). */
desc = XNEW (class tree_niter_desc);
if (!number_of_iterations_exit (data->current_loop,
exit, desc, true)
|| contains_abnormal_ssa_name_p (desc->niter))
{
XDELETE (desc);
desc = NULL;
}
data->niters->put (exit, desc);
}
else
desc = *slot;
return desc;
}
/* Returns the structure describing number of iterations determined from
single dominating exit of DATA->current_loop, or NULL if something
goes wrong. */
static class tree_niter_desc *
niter_for_single_dom_exit (struct ivopts_data *data)
{
edge exit = single_dom_exit (data->current_loop);
if (!exit)
return NULL;
return niter_for_exit (data, exit);
}
/* Initializes data structures used by the iv optimization pass, stored
in DATA. */
static void
tree_ssa_iv_optimize_init (struct ivopts_data *data)
{
data->version_info_size = 2 * num_ssa_names;
data->version_info = XCNEWVEC (struct version_info, data->version_info_size);
data->relevant = BITMAP_ALLOC (NULL);
data->important_candidates = BITMAP_ALLOC (NULL);
data->max_inv_var_id = 0;
data->max_inv_expr_id = 0;
data->niters = NULL;
data->vgroups.create (20);
data->vcands.create (20);
data->inv_expr_tab = new hash_table<iv_inv_expr_hasher> (10);
data->name_expansion_cache = NULL;
data->base_object_map = NULL;
data->iv_common_cand_tab = new hash_table<iv_common_cand_hasher> (10);
data->iv_common_cands.create (20);
decl_rtl_to_reset.create (20);
gcc_obstack_init (&data->iv_obstack);
}
/* walk_tree callback for determine_base_object. */
static tree
determine_base_object_1 (tree *tp, int *walk_subtrees, void *wdata)
{
tree_code code = TREE_CODE (*tp);
tree obj = NULL_TREE;
if (code == ADDR_EXPR)
{
tree base = get_base_address (TREE_OPERAND (*tp, 0));
if (!base)
obj = *tp;
else if (TREE_CODE (base) != MEM_REF)
obj = fold_convert (ptr_type_node, build_fold_addr_expr (base));
}
else if (code == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (*tp)))
obj = fold_convert (ptr_type_node, *tp);
if (!obj)
{
if (!EXPR_P (*tp))
*walk_subtrees = 0;
return NULL_TREE;
}
/* Record special node for multiple base objects and stop. */
if (*static_cast<tree *> (wdata))
{
*static_cast<tree *> (wdata) = integer_zero_node;
return integer_zero_node;
}
/* Record the base object and continue looking. */
*static_cast<tree *> (wdata) = obj;
return NULL_TREE;
}
/* Returns a memory object to that EXPR points with caching. Return NULL if we
are able to determine that it does not point to any such object; specially
return integer_zero_node if EXPR contains multiple base objects. */
static tree
determine_base_object (struct ivopts_data *data, tree expr)
{
tree *slot, obj = NULL_TREE;
if (data->base_object_map)
{
if ((slot = data->base_object_map->get(expr)) != NULL)
return *slot;
}
else
data->base_object_map = new hash_map<tree, tree>;
(void) walk_tree_without_duplicates (&expr, determine_base_object_1, &obj);
data->base_object_map->put (expr, obj);
return obj;
}
/* Return true if address expression with non-DECL_P operand appears
in EXPR. */
static bool
contain_complex_addr_expr (tree expr)
{
bool res = false;
STRIP_NOPS (expr);
switch (TREE_CODE (expr))
{
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
res |= contain_complex_addr_expr (TREE_OPERAND (expr, 0));
res |= contain_complex_addr_expr (TREE_OPERAND (expr, 1));
break;
case ADDR_EXPR:
return (!DECL_P (TREE_OPERAND (expr, 0)));
default:
return false;
}
return res;
}
/* Allocates an induction variable with given initial value BASE and step STEP
for loop LOOP. NO_OVERFLOW implies the iv doesn't overflow. */
static struct iv *
alloc_iv (struct ivopts_data *data, tree base, tree step,
bool no_overflow = false)
{
tree expr = base;
struct iv *iv = (struct iv*) obstack_alloc (&data->iv_obstack,
sizeof (struct iv));
gcc_assert (step != NULL_TREE);
/* Lower address expression in base except ones with DECL_P as operand.
By doing this:
1) More accurate cost can be computed for address expressions;
2) Duplicate candidates won't be created for bases in different
forms, like &a[0] and &a. */
STRIP_NOPS (expr);
if ((TREE_CODE (expr) == ADDR_EXPR && !DECL_P (TREE_OPERAND (expr, 0)))
|| contain_complex_addr_expr (expr))
{
aff_tree comb;
tree_to_aff_combination (expr, TREE_TYPE (expr), &comb);
base = fold_convert (TREE_TYPE (base), aff_combination_to_tree (&comb));
}
iv->base = base;
iv->base_object = determine_base_object (data, base);
iv->step = step;
iv->biv_p = false;
iv->nonlin_use = NULL;
iv->ssa_name = NULL_TREE;
if (!no_overflow
&& !iv_can_overflow_p (data->current_loop, TREE_TYPE (base),
base, step))
no_overflow = true;
iv->no_overflow = no_overflow;
iv->have_address_use = false;
return iv;
}
/* Sets STEP and BASE for induction variable IV. NO_OVERFLOW implies the IV
doesn't overflow. */
static void
set_iv (struct ivopts_data *data, tree iv, tree base, tree step,
bool no_overflow)
{
struct version_info *info = name_info (data, iv);
gcc_assert (!info->iv);
bitmap_set_bit (data->relevant, SSA_NAME_VERSION (iv));
info->iv = alloc_iv (data, base, step, no_overflow);
info->iv->ssa_name = iv;
}
/* Finds induction variable declaration for VAR. */
static struct iv *
get_iv (struct ivopts_data *data, tree var)
{
basic_block bb;
tree type = TREE_TYPE (var);
if (!POINTER_TYPE_P (type)
&& !INTEGRAL_TYPE_P (type))
return NULL;
if (!name_info (data, var)->iv)
{
bb = gimple_bb (SSA_NAME_DEF_STMT (var));
if (!bb
|| !flow_bb_inside_loop_p (data->current_loop, bb))
{
if (POINTER_TYPE_P (type))
type = sizetype;
set_iv (data, var, var, build_int_cst (type, 0), true);
}
}
return name_info (data, var)->iv;
}
/* Return the first non-invariant ssa var found in EXPR. */
static tree
extract_single_var_from_expr (tree expr)
{
int i, n;
tree tmp;
enum tree_code code;
if (!expr || is_gimple_min_invariant (expr))
return NULL;
code = TREE_CODE (expr);
if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
{
n = TREE_OPERAND_LENGTH (expr);
for (i = 0; i < n; i++)
{
tmp = extract_single_var_from_expr (TREE_OPERAND (expr, i));
if (tmp)
return tmp;
}
}
return (TREE_CODE (expr) == SSA_NAME) ? expr : NULL;
}
/* Finds basic ivs. */
static bool
find_bivs (struct ivopts_data *data)
{
gphi *phi;
affine_iv iv;
tree step, type, base, stop;
bool found = false;
class loop *loop = data->current_loop;
gphi_iterator psi;
for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi))
{
phi = psi.phi ();
if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)))
continue;
if (virtual_operand_p (PHI_RESULT (phi)))
continue;
if (!simple_iv (loop, loop, PHI_RESULT (phi), &iv, true))
continue;
if (integer_zerop (iv.step))
continue;
step = iv.step;
base = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop));
/* Stop expanding iv base at the first ssa var referred by iv step.
Ideally we should stop at any ssa var, because that's expensive
and unusual to happen, we just do it on the first one.
See PR64705 for the rationale. */
stop = extract_single_var_from_expr (step);
base = expand_simple_operations (base, stop);
if (contains_abnormal_ssa_name_p (base)
|| contains_abnormal_ssa_name_p (step))
continue;
type = TREE_TYPE (PHI_RESULT (phi));
base = fold_convert (type, base);
if (step)
{
if (POINTER_TYPE_P (type))
step = convert_to_ptrofftype (step);
else
step = fold_convert (type, step);
}
set_iv (data, PHI_RESULT (phi), base, step, iv.no_overflow);
found = true;
}
return found;
}
/* Marks basic ivs. */
static void
mark_bivs (struct ivopts_data *data)
{
gphi *phi;
gimple *def;
tree var;
struct iv *iv, *incr_iv;
class loop *loop = data->current_loop;
basic_block incr_bb;
gphi_iterator psi;
data->bivs_not_used_in_addr = 0;
for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi))
{
phi = psi.phi ();
iv = get_iv (data, PHI_RESULT (phi));
if (!iv)
continue;
var = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop));
def = SSA_NAME_DEF_STMT (var);
/* Don't mark iv peeled from other one as biv. */
if (def
&& gimple_code (def) == GIMPLE_PHI
&& gimple_bb (def) == loop->header)
continue;
incr_iv = get_iv (data, var);
if (!incr_iv)
continue;
/* If the increment is in the subloop, ignore it. */
incr_bb = gimple_bb (SSA_NAME_DEF_STMT (var));
if (incr_bb->loop_father != data->current_loop
|| (incr_bb->flags & BB_IRREDUCIBLE_LOOP))
continue;
iv->biv_p = true;
incr_iv->biv_p = true;
if (iv->no_overflow)
data->bivs_not_used_in_addr++;
if (incr_iv->no_overflow)
data->bivs_not_used_in_addr++;
}
}
/* Checks whether STMT defines a linear induction variable and stores its
parameters to IV. */
static bool
find_givs_in_stmt_scev (struct ivopts_data *data, gimple *stmt, affine_iv *iv)
{
tree lhs, stop;
class loop *loop = data->current_loop;
iv->base = NULL_TREE;
iv->step = NULL_TREE;
if (gimple_code (stmt) != GIMPLE_ASSIGN)
return false;
lhs = gimple_assign_lhs (stmt);
if (TREE_CODE (lhs) != SSA_NAME)
return false;
if (!simple_iv (loop, loop_containing_stmt (stmt), lhs, iv, true))
return false;
/* Stop expanding iv base at the first ssa var referred by iv step.
Ideally we should stop at any ssa var, because that's expensive
and unusual to happen, we just do it on the first one.
See PR64705 for the rationale. */
stop = extract_single_var_from_expr (iv->step);
iv->base = expand_simple_operations (iv->base, stop);
if (contains_abnormal_ssa_name_p (iv->base)
|| contains_abnormal_ssa_name_p (iv->step))
return false;
/* If STMT could throw, then do not consider STMT as defining a GIV.
While this will suppress optimizations, we cannot safely delete this
GIV and associated statements, even if it appears it is not used. */
if (stmt_could_throw_p (cfun, stmt))
return false;
return true;
}
/* Finds general ivs in statement STMT. */
static void
find_givs_in_stmt (struct ivopts_data *data, gimple *stmt)
{
affine_iv iv;
if (!find_givs_in_stmt_scev (data, stmt, &iv))
return;
set_iv (data, gimple_assign_lhs (stmt), iv.base, iv.step, iv.no_overflow);
}
/* Finds general ivs in basic block BB. */
static void
find_givs_in_bb (struct ivopts_data *data, basic_block bb)
{
gimple_stmt_iterator bsi;
for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
find_givs_in_stmt (data, gsi_stmt (bsi));
}
/* Finds general ivs. */
static void
find_givs (struct ivopts_data *data, basic_block *body)
{
class loop *loop = data->current_loop;
unsigned i;
for (i = 0; i < loop->num_nodes; i++)
find_givs_in_bb (data, body[i]);
}
/* For each ssa name defined in LOOP determines whether it is an induction
variable and if so, its initial value and step. */
static bool
find_induction_variables (struct ivopts_data *data, basic_block *body)
{
unsigned i;
bitmap_iterator bi;
if (!find_bivs (data))
return false;
find_givs (data, body);
mark_bivs (data);
if (dump_file && (dump_flags & TDF_DETAILS))
{
class tree_niter_desc *niter = niter_for_single_dom_exit (data);
if (niter)
{
fprintf (dump_file, " number of iterations ");
print_generic_expr (dump_file, niter->niter, TDF_SLIM);
if (!integer_zerop (niter->may_be_zero))
{
fprintf (dump_file, "; zero if ");
print_generic_expr (dump_file, niter->may_be_zero, TDF_SLIM);
}
fprintf (dump_file, "\n");
};
fprintf (dump_file, "\n<Induction Vars>:\n");
EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
{
struct version_info *info = ver_info (data, i);
if (info->iv && info->iv->step && !integer_zerop (info->iv->step))
dump_iv (dump_file, ver_info (data, i)->iv, true, 0);
}
}
return true;
}
/* Records a use of TYPE at *USE_P in STMT whose value is IV in GROUP.
For address type use, ADDR_BASE is the stripped IV base, ADDR_OFFSET
is the const offset stripped from IV base and MEM_TYPE is the type
of the memory being addressed. For uses of other types, ADDR_BASE
and ADDR_OFFSET are zero by default and MEM_TYPE is NULL_TREE. */
static struct iv_use *
record_use (struct iv_group *group, tree *use_p, struct iv *iv,
gimple *stmt, enum use_type type, tree mem_type,
tree addr_base, poly_uint64 addr_offset)
{
struct iv_use *use = XCNEW (struct iv_use);
use->id = group->vuses.length ();
use->group_id = group->id;
use->type = type;
use->mem_type = mem_type;
use->iv = iv;
use->stmt = stmt;
use->op_p = use_p;
use->addr_base = addr_base;
use->addr_offset = addr_offset;
group->vuses.safe_push (use);
return use;
}
/* Checks whether OP is a loop-level invariant and if so, records it.
NONLINEAR_USE is true if the invariant is used in a way we do not
handle specially. */
static void
record_invariant (struct ivopts_data *data, tree op, bool nonlinear_use)
{
basic_block bb;
struct version_info *info;
if (TREE_CODE (op) != SSA_NAME
|| virtual_operand_p (op))
return;
bb = gimple_bb (SSA_NAME_DEF_STMT (op));
if (bb
&& flow_bb_inside_loop_p (data->current_loop, bb))
return;
info = name_info (data, op);
info->name = op;
info->has_nonlin_use |= nonlinear_use;
if (!info->inv_id)
info->inv_id = ++data->max_inv_var_id;
bitmap_set_bit (data->relevant, SSA_NAME_VERSION (op));
}
/* Record a group of TYPE. */
static struct iv_group *
record_group (struct ivopts_data *data, enum use_type type)
{
struct iv_group *group = XCNEW (struct iv_group);
group->id = data->vgroups.length ();
group->type = type;
group->related_cands = BITMAP_ALLOC (NULL);
group->vuses.create (1);
group->doloop_p = false;
data->vgroups.safe_push (group);
return group;
}
/* Record a use of TYPE at *USE_P in STMT whose value is IV in a group.
New group will be created if there is no existing group for the use.
MEM_TYPE is the type of memory being addressed, or NULL if this
isn't an address reference. */
static struct iv_use *
record_group_use (struct ivopts_data *data, tree *use_p,
struct iv *iv, gimple *stmt, enum use_type type,
tree mem_type)
{
tree addr_base = NULL;
struct iv_group *group = NULL;
poly_uint64 addr_offset = 0;
/* Record non address type use in a new group. */
if (address_p (type))
{
unsigned int i;
addr_base = strip_offset (iv->base, &addr_offset);
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_use *use;
group = data->vgroups[i];
use = group->vuses[0];
if (!address_p (use->type))
continue;
/* Check if it has the same stripped base and step. */
if (operand_equal_p (iv->base_object, use->iv->base_object, 0)
&& operand_equal_p (iv->step, use->iv->step, 0)
&& operand_equal_p (addr_base, use->addr_base, 0))
break;
}
if (i == data->vgroups.length ())
group = NULL;
}
if (!group)
group = record_group (data, type);
return record_use (group, use_p, iv, stmt, type, mem_type,
addr_base, addr_offset);
}
/* Checks whether the use OP is interesting and if so, records it. */
static struct iv_use *
find_interesting_uses_op (struct ivopts_data *data, tree op)
{
struct iv *iv;
gimple *stmt;
struct iv_use *use;
if (TREE_CODE (op) != SSA_NAME)
return NULL;
iv = get_iv (data, op);
if (!iv)
return NULL;
if (iv->nonlin_use)
{
gcc_assert (iv->nonlin_use->type == USE_NONLINEAR_EXPR);
return iv->nonlin_use;
}
if (integer_zerop (iv->step))
{
record_invariant (data, op, true);
return NULL;
}
stmt = SSA_NAME_DEF_STMT (op);
gcc_assert (gimple_code (stmt) == GIMPLE_PHI || is_gimple_assign (stmt));
use = record_group_use (data, NULL, iv, stmt, USE_NONLINEAR_EXPR, NULL_TREE);
iv->nonlin_use = use;
return use;
}
/* Indicate how compare type iv_use can be handled. */
enum comp_iv_rewrite
{
COMP_IV_NA,
/* We may rewrite compare type iv_use by expressing value of the iv_use. */
COMP_IV_EXPR,
/* We may rewrite compare type iv_uses on both sides of comparison by
expressing value of each iv_use. */
COMP_IV_EXPR_2,
/* We may rewrite compare type iv_use by expressing value of the iv_use
or by eliminating it with other iv_cand. */
COMP_IV_ELIM
};
/* Given a condition in statement STMT, checks whether it is a compare
of an induction variable and an invariant. If this is the case,
CONTROL_VAR is set to location of the iv, BOUND to the location of
the invariant, IV_VAR and IV_BOUND are set to the corresponding
induction variable descriptions, and true is returned. If this is not
the case, CONTROL_VAR and BOUND are set to the arguments of the
condition and false is returned. */
static enum comp_iv_rewrite
extract_cond_operands (struct ivopts_data *data, gimple *stmt,
tree **control_var, tree **bound,
struct iv **iv_var, struct iv **iv_bound)
{
/* The objects returned when COND has constant operands. */
static struct iv const_iv;
static tree zero;
tree *op0 = &zero, *op1 = &zero;
struct iv *iv0 = &const_iv, *iv1 = &const_iv;
enum comp_iv_rewrite rewrite_type = COMP_IV_NA;
if (gimple_code (stmt) == GIMPLE_COND)
{
gcond *cond_stmt = as_a <gcond *> (stmt);
op0 = gimple_cond_lhs_ptr (cond_stmt);
op1 = gimple_cond_rhs_ptr (cond_stmt);
}
else
{
op0 = gimple_assign_rhs1_ptr (stmt);
op1 = gimple_assign_rhs2_ptr (stmt);
}
zero = integer_zero_node;
const_iv.step = integer_zero_node;
if (TREE_CODE (*op0) == SSA_NAME)
iv0 = get_iv (data, *op0);
if (TREE_CODE (*op1) == SSA_NAME)
iv1 = get_iv (data, *op1);
/* If both sides of comparison are IVs. We can express ivs on both end. */
if (iv0 && iv1 && !integer_zerop (iv0->step) && !integer_zerop (iv1->step))
{
rewrite_type = COMP_IV_EXPR_2;
goto end;
}
/* If none side of comparison is IV. */
if ((!iv0 || integer_zerop (iv0->step))
&& (!iv1 || integer_zerop (iv1->step)))
goto end;
/* Control variable may be on the other side. */
if (!iv0 || integer_zerop (iv0->step))
{
std::swap (op0, op1);
std::swap (iv0, iv1);
}
/* If one side is IV and the other side isn't loop invariant. */
if (!iv1)
rewrite_type = COMP_IV_EXPR;
/* If one side is IV and the other side is loop invariant. */
else if (!integer_zerop (iv0->step) && integer_zerop (iv1->step))
rewrite_type = COMP_IV_ELIM;
end:
if (control_var)
*control_var = op0;
if (iv_var)
*iv_var = iv0;
if (bound)
*bound = op1;
if (iv_bound)
*iv_bound = iv1;
return rewrite_type;
}
/* Checks whether the condition in STMT is interesting and if so,
records it. */
static void
find_interesting_uses_cond (struct ivopts_data *data, gimple *stmt)
{
tree *var_p, *bound_p;
struct iv *var_iv, *bound_iv;
enum comp_iv_rewrite ret;
ret = extract_cond_operands (data, stmt,
&var_p, &bound_p, &var_iv, &bound_iv);
if (ret == COMP_IV_NA)
{
find_interesting_uses_op (data, *var_p);
find_interesting_uses_op (data, *bound_p);
return;
}
record_group_use (data, var_p, var_iv, stmt, USE_COMPARE, NULL_TREE);
/* Record compare type iv_use for iv on the other side of comparison. */
if (ret == COMP_IV_EXPR_2)
record_group_use (data, bound_p, bound_iv, stmt, USE_COMPARE, NULL_TREE);
}
/* Returns the outermost loop EXPR is obviously invariant in
relative to the loop LOOP, i.e. if all its operands are defined
outside of the returned loop. Returns NULL if EXPR is not
even obviously invariant in LOOP. */
class loop *
outermost_invariant_loop_for_expr (class loop *loop, tree expr)
{
basic_block def_bb;
unsigned i, len;
if (is_gimple_min_invariant (expr))
return current_loops->tree_root;
if (TREE_CODE (expr) == SSA_NAME)
{
def_bb = gimple_bb (SSA_NAME_DEF_STMT (expr));
if (def_bb)
{
if (flow_bb_inside_loop_p (loop, def_bb))
return NULL;
return superloop_at_depth (loop,
loop_depth (def_bb->loop_father) + 1);
}
return current_loops->tree_root;
}
if (!EXPR_P (expr))
return NULL;
unsigned maxdepth = 0;
len = TREE_OPERAND_LENGTH (expr);
for (i = 0; i < len; i++)
{
class loop *ivloop;
if (!TREE_OPERAND (expr, i))
continue;
ivloop = outermost_invariant_loop_for_expr (loop, TREE_OPERAND (expr, i));
if (!ivloop)
return NULL;
maxdepth = MAX (maxdepth, loop_depth (ivloop));
}
return superloop_at_depth (loop, maxdepth);
}
/* Returns true if expression EXPR is obviously invariant in LOOP,
i.e. if all its operands are defined outside of the LOOP. LOOP
should not be the function body. */
bool
expr_invariant_in_loop_p (class loop *loop, tree expr)
{
basic_block def_bb;
unsigned i, len;
gcc_assert (loop_depth (loop) > 0);
if (is_gimple_min_invariant (expr))
return true;
if (TREE_CODE (expr) == SSA_NAME)
{
def_bb = gimple_bb (SSA_NAME_DEF_STMT (expr));
if (def_bb
&& flow_bb_inside_loop_p (loop, def_bb))
return false;
return true;
}
if (!EXPR_P (expr))
return false;
len = TREE_OPERAND_LENGTH (expr);
for (i = 0; i < len; i++)
if (TREE_OPERAND (expr, i)
&& !expr_invariant_in_loop_p (loop, TREE_OPERAND (expr, i)))
return false;
return true;
}
/* Given expression EXPR which computes inductive values with respect
to loop recorded in DATA, this function returns biv from which EXPR
is derived by tracing definition chains of ssa variables in EXPR. */
static struct iv*
find_deriving_biv_for_expr (struct ivopts_data *data, tree expr)
{
struct iv *iv;
unsigned i, n;
tree e2, e1;
enum tree_code code;
gimple *stmt;
if (expr == NULL_TREE)
return NULL;
if (is_gimple_min_invariant (expr))
return NULL;
code = TREE_CODE (expr);
if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
{
n = TREE_OPERAND_LENGTH (expr);
for (i = 0; i < n; i++)
{
iv = find_deriving_biv_for_expr (data, TREE_OPERAND (expr, i));
if (iv)
return iv;
}
}
/* Stop if it's not ssa name. */
if (code != SSA_NAME)
return NULL;
iv = get_iv (data, expr);
if (!iv || integer_zerop (iv->step))
return NULL;
else if (iv->biv_p)
return iv;
stmt = SSA_NAME_DEF_STMT (expr);
if (gphi *phi = dyn_cast <gphi *> (stmt))
{
ssa_op_iter iter;
use_operand_p use_p;
basic_block phi_bb = gimple_bb (phi);
/* Skip loop header PHI that doesn't define biv. */
if (phi_bb->loop_father == data->current_loop)
return NULL;
if (virtual_operand_p (gimple_phi_result (phi)))
return NULL;
FOR_EACH_PHI_ARG (use_p, phi, iter, SSA_OP_USE)
{
tree use = USE_FROM_PTR (use_p);
iv = find_deriving_biv_for_expr (data, use);
if (iv)
return iv;
}
return NULL;
}
if (gimple_code (stmt) != GIMPLE_ASSIGN)
return NULL;
e1 = gimple_assign_rhs1 (stmt);
code = gimple_assign_rhs_code (stmt);
if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
return find_deriving_biv_for_expr (data, e1);
switch (code)
{
case MULT_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
case POINTER_PLUS_EXPR:
/* Increments, decrements and multiplications by a constant
are simple. */
e2 = gimple_assign_rhs2 (stmt);
iv = find_deriving_biv_for_expr (data, e2);
if (iv)
return iv;
gcc_fallthrough ();
CASE_CONVERT:
/* Casts are simple. */
return find_deriving_biv_for_expr (data, e1);
default:
break;
}
return NULL;
}
/* Record BIV, its predecessor and successor that they are used in
address type uses. */
static void
record_biv_for_address_use (struct ivopts_data *data, struct iv *biv)
{
unsigned i;
tree type, base_1, base_2;
bitmap_iterator bi;
if (!biv || !biv->biv_p || integer_zerop (biv->step)
|| biv->have_address_use || !biv->no_overflow)
return;
type = TREE_TYPE (biv->base);
if (!INTEGRAL_TYPE_P (type))
return;
biv->have_address_use = true;
data->bivs_not_used_in_addr--;
base_1 = fold_build2 (PLUS_EXPR, type, biv->base, biv->step);
EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
{
struct iv *iv = ver_info (data, i)->iv;
if (!iv || !iv->biv_p || integer_zerop (iv->step)
|| iv->have_address_use || !iv->no_overflow)
continue;
if (type != TREE_TYPE (iv->base)
|| !INTEGRAL_TYPE_P (TREE_TYPE (iv->base)))
continue;
if (!operand_equal_p (biv->step, iv->step, 0))
continue;
base_2 = fold_build2 (PLUS_EXPR, type, iv->base, iv->step);
if (operand_equal_p (base_1, iv->base, 0)
|| operand_equal_p (base_2, biv->base, 0))
{
iv->have_address_use = true;
data->bivs_not_used_in_addr--;
}
}
}
/* Cumulates the steps of indices into DATA and replaces their values with the
initial ones. Returns false when the value of the index cannot be determined.
Callback for for_each_index. */
struct ifs_ivopts_data
{
struct ivopts_data *ivopts_data;
gimple *stmt;
tree step;
};
static bool
idx_find_step (tree base, tree *idx, void *data)
{
struct ifs_ivopts_data *dta = (struct ifs_ivopts_data *) data;
struct iv *iv;
bool use_overflow_semantics = false;
tree step, iv_base, iv_step, lbound, off;
class loop *loop = dta->ivopts_data->current_loop;
/* If base is a component ref, require that the offset of the reference
be invariant. */
if (TREE_CODE (base) == COMPONENT_REF)
{
off = component_ref_field_offset (base);
return expr_invariant_in_loop_p (loop, off);
}
/* If base is array, first check whether we will be able to move the
reference out of the loop (in order to take its address in strength
reduction). In order for this to work we need both lower bound
and step to be loop invariants. */
if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF)
{
/* Moreover, for a range, the size needs to be invariant as well. */
if (TREE_CODE (base) == ARRAY_RANGE_REF
&& !expr_invariant_in_loop_p (loop, TYPE_SIZE (TREE_TYPE (base))))
return false;
step = array_ref_element_size (base);
lbound = array_ref_low_bound (base);
if (!expr_invariant_in_loop_p (loop, step)
|| !expr_invariant_in_loop_p (loop, lbound))
return false;
}
if (TREE_CODE (*idx) != SSA_NAME)
return true;
iv = get_iv (dta->ivopts_data, *idx);
if (!iv)
return false;
/* XXX We produce for a base of *D42 with iv->base being &x[0]
*&x[0], which is not folded and does not trigger the
ARRAY_REF path below. */
*idx = iv->base;
if (integer_zerop (iv->step))
return true;
if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF)
{
step = array_ref_element_size (base);
/* We only handle addresses whose step is an integer constant. */
if (TREE_CODE (step) != INTEGER_CST)
return false;
}
else
/* The step for pointer arithmetics already is 1 byte. */
step = size_one_node;
iv_base = iv->base;
iv_step = iv->step;
if (iv->no_overflow && nowrap_type_p (TREE_TYPE (iv_step)))
use_overflow_semantics = true;
if (!convert_affine_scev (dta->ivopts_data->current_loop,
sizetype, &iv_base, &iv_step, dta->stmt,
use_overflow_semantics))
{
/* The index might wrap. */
return false;
}
step = fold_build2 (MULT_EXPR, sizetype, step, iv_step);
dta->step = fold_build2 (PLUS_EXPR, sizetype, dta->step, step);
if (dta->ivopts_data->bivs_not_used_in_addr)
{
if (!iv->biv_p)
iv = find_deriving_biv_for_expr (dta->ivopts_data, iv->ssa_name);
record_biv_for_address_use (dta->ivopts_data, iv);
}
return true;
}
/* Records use in index IDX. Callback for for_each_index. Ivopts data
object is passed to it in DATA. */
static bool
idx_record_use (tree base, tree *idx,
void *vdata)
{
struct ivopts_data *data = (struct ivopts_data *) vdata;
find_interesting_uses_op (data, *idx);
if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF)
{
if (TREE_OPERAND (base, 2))
find_interesting_uses_op (data, TREE_OPERAND (base, 2));
if (TREE_OPERAND (base, 3))
find_interesting_uses_op (data, TREE_OPERAND (base, 3));
}
return true;
}
/* If we can prove that TOP = cst * BOT for some constant cst,
store cst to MUL and return true. Otherwise return false.
The returned value is always sign-extended, regardless of the
signedness of TOP and BOT. */
static bool
constant_multiple_of (tree top, tree bot, widest_int *mul)
{
tree mby;
enum tree_code code;
unsigned precision = TYPE_PRECISION (TREE_TYPE (top));
widest_int res, p0, p1;
STRIP_NOPS (top);
STRIP_NOPS (bot);
if (operand_equal_p (top, bot, 0))
{
*mul = 1;
return true;
}
code = TREE_CODE (top);
switch (code)
{
case MULT_EXPR:
mby = TREE_OPERAND (top, 1);
if (TREE_CODE (mby) != INTEGER_CST)
return false;
if (!constant_multiple_of (TREE_OPERAND (top, 0), bot, &res))
return false;
*mul = wi::sext (res * wi::to_widest (mby), precision);
return true;
case PLUS_EXPR:
case MINUS_EXPR:
if (!constant_multiple_of (TREE_OPERAND (top, 0), bot, &p0)
|| !constant_multiple_of (TREE_OPERAND (top, 1), bot, &p1))
return false;
if (code == MINUS_EXPR)
p1 = -p1;
*mul = wi::sext (p0 + p1, precision);
return true;
case INTEGER_CST:
if (TREE_CODE (bot) != INTEGER_CST)
return false;
p0 = widest_int::from (wi::to_wide (top), SIGNED);
p1 = widest_int::from (wi::to_wide (bot), SIGNED);
if (p1 == 0)
return false;
*mul = wi::sext (wi::divmod_trunc (p0, p1, SIGNED, &res), precision);
return res == 0;
default:
if (POLY_INT_CST_P (top)
&& POLY_INT_CST_P (bot)
&& constant_multiple_p (wi::to_poly_widest (top),
wi::to_poly_widest (bot), mul))
return true;
return false;
}
}
/* Return true if memory reference REF with step STEP may be unaligned. */
static bool
may_be_unaligned_p (tree ref, tree step)
{
/* TARGET_MEM_REFs are translated directly to valid MEMs on the target,
thus they are not misaligned. */
if (TREE_CODE (ref) == TARGET_MEM_REF)
return false;
unsigned int align = TYPE_ALIGN (TREE_TYPE (ref));
if (GET_MODE_ALIGNMENT (TYPE_MODE (TREE_TYPE (ref))) > align)
align = GET_MODE_ALIGNMENT (TYPE_MODE (TREE_TYPE (ref)));
unsigned HOST_WIDE_INT bitpos;
unsigned int ref_align;
get_object_alignment_1 (ref, &ref_align, &bitpos);
if (ref_align < align
|| (bitpos % align) != 0
|| (bitpos % BITS_PER_UNIT) != 0)
return true;
unsigned int trailing_zeros = tree_ctz (step);
if (trailing_zeros < HOST_BITS_PER_INT
&& (1U << trailing_zeros) * BITS_PER_UNIT < align)
return true;
return false;
}
/* Return true if EXPR may be non-addressable. */
bool
may_be_nonaddressable_p (tree expr)
{
switch (TREE_CODE (expr))
{
case VAR_DECL:
/* Check if it's a register variable. */
return DECL_HARD_REGISTER (expr);
case TARGET_MEM_REF:
/* TARGET_MEM_REFs are translated directly to valid MEMs on the
target, thus they are always addressable. */
return false;
case MEM_REF:
/* Likewise for MEM_REFs, modulo the storage order. */
return REF_REVERSE_STORAGE_ORDER (expr);
case BIT_FIELD_REF:
if (REF_REVERSE_STORAGE_ORDER (expr))
return true;
return may_be_nonaddressable_p (TREE_OPERAND (expr, 0));
case COMPONENT_REF:
if (TYPE_REVERSE_STORAGE_ORDER (TREE_TYPE (TREE_OPERAND (expr, 0))))
return true;
return DECL_NONADDRESSABLE_P (TREE_OPERAND (expr, 1))
|| may_be_nonaddressable_p (TREE_OPERAND (expr, 0));
case ARRAY_REF:
case ARRAY_RANGE_REF:
if (TYPE_REVERSE_STORAGE_ORDER (TREE_TYPE (TREE_OPERAND (expr, 0))))
return true;
return may_be_nonaddressable_p (TREE_OPERAND (expr, 0));
case VIEW_CONVERT_EXPR:
/* This kind of view-conversions may wrap non-addressable objects
and make them look addressable. After some processing the
non-addressability may be uncovered again, causing ADDR_EXPRs
of inappropriate objects to be built. */
if (is_gimple_reg (TREE_OPERAND (expr, 0))
|| !is_gimple_addressable (TREE_OPERAND (expr, 0)))
return true;
return may_be_nonaddressable_p (TREE_OPERAND (expr, 0));
CASE_CONVERT:
return true;
default:
break;
}
return false;
}
/* Finds addresses in *OP_P inside STMT. */
static void
find_interesting_uses_address (struct ivopts_data *data, gimple *stmt,
tree *op_p)
{
tree base = *op_p, step = size_zero_node;
struct iv *civ;
struct ifs_ivopts_data ifs_ivopts_data;
/* Do not play with volatile memory references. A bit too conservative,
perhaps, but safe. */
if (gimple_has_volatile_ops (stmt))
goto fail;
/* Ignore bitfields for now. Not really something terribly complicated
to handle. TODO. */
if (TREE_CODE (base) == BIT_FIELD_REF)
goto fail;
base = unshare_expr (base);
if (TREE_CODE (base) == TARGET_MEM_REF)
{
tree type = build_pointer_type (TREE_TYPE (base));
tree astep;
if (TMR_BASE (base)
&& TREE_CODE (TMR_BASE (base)) == SSA_NAME)
{
civ = get_iv (data, TMR_BASE (base));
if (!civ)
goto fail;
TMR_BASE (base) = civ->base;
step = civ->step;
}
if (TMR_INDEX2 (base)
&& TREE_CODE (TMR_INDEX2 (base)) == SSA_NAME)
{
civ = get_iv (data, TMR_INDEX2 (base));
if (!civ)
goto fail;
TMR_INDEX2 (base) = civ->base;
step = civ->step;
}
if (TMR_INDEX (base)
&& TREE_CODE (TMR_INDEX (base)) == SSA_NAME)
{
civ = get_iv (data, TMR_INDEX (base));
if (!civ)
goto fail;
TMR_INDEX (base) = civ->base;
astep = civ->step;
if (astep)
{
if (TMR_STEP (base))
astep = fold_build2 (MULT_EXPR, type, TMR_STEP (base), astep);
step = fold_build2 (PLUS_EXPR, type, step, astep);
}
}
if (integer_zerop (step))
goto fail;
base = tree_mem_ref_addr (type, base);
}
else
{
ifs_ivopts_data.ivopts_data = data;
ifs_ivopts_data.stmt = stmt;
ifs_ivopts_data.step = size_zero_node;
if (!for_each_index (&base, idx_find_step, &ifs_ivopts_data)
|| integer_zerop (ifs_ivopts_data.step))
goto fail;
step = ifs_ivopts_data.step;
/* Check that the base expression is addressable. This needs
to be done after substituting bases of IVs into it. */
if (may_be_nonaddressable_p (base))
goto fail;
/* Moreover, on strict alignment platforms, check that it is
sufficiently aligned. */
if (STRICT_ALIGNMENT && may_be_unaligned_p (base, step))
goto fail;
base = build_fold_addr_expr (base);
/* Substituting bases of IVs into the base expression might
have caused folding opportunities. */
if (TREE_CODE (base) == ADDR_EXPR)
{
tree *ref = &TREE_OPERAND (base, 0);
while (handled_component_p (*ref))
ref = &TREE_OPERAND (*ref, 0);
if (TREE_CODE (*ref) == MEM_REF)
{
tree tem = fold_binary (MEM_REF, TREE_TYPE (*ref),
TREE_OPERAND (*ref, 0),
TREE_OPERAND (*ref, 1));
if (tem)
*ref = tem;
}
}
}
civ = alloc_iv (data, base, step);
/* Fail if base object of this memory reference is unknown. */
if (civ->base_object == NULL_TREE)
goto fail;
record_group_use (data, op_p, civ, stmt, USE_REF_ADDRESS, TREE_TYPE (*op_p));
return;
fail:
for_each_index (op_p, idx_record_use, data);
}
/* Finds and records invariants used in STMT. */
static void
find_invariants_stmt (struct ivopts_data *data, gimple *stmt)
{
ssa_op_iter iter;
use_operand_p use_p;
tree op;
FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE)
{
op = USE_FROM_PTR (use_p);
record_invariant (data, op, false);
}
}
/* CALL calls an internal function. If operand *OP_P will become an
address when the call is expanded, return the type of the memory
being addressed, otherwise return null. */
static tree
get_mem_type_for_internal_fn (gcall *call, tree *op_p)
{
switch (gimple_call_internal_fn (call))
{
case IFN_MASK_LOAD:
case IFN_MASK_LOAD_LANES:
case IFN_LEN_LOAD:
if (op_p == gimple_call_arg_ptr (call, 0))
return TREE_TYPE (gimple_call_lhs (call));
return NULL_TREE;
case IFN_MASK_STORE:
case IFN_MASK_STORE_LANES:
case IFN_LEN_STORE:
if (op_p == gimple_call_arg_ptr (call, 0))
return TREE_TYPE (gimple_call_arg (call, 3));
return NULL_TREE;
default:
return NULL_TREE;
}
}
/* IV is a (non-address) iv that describes operand *OP_P of STMT.
Return true if the operand will become an address when STMT
is expanded and record the associated address use if so. */
static bool
find_address_like_use (struct ivopts_data *data, gimple *stmt, tree *op_p,
struct iv *iv)
{
/* Fail if base object of this memory reference is unknown. */
if (iv->base_object == NULL_TREE)
return false;
tree mem_type = NULL_TREE;
if (gcall *call = dyn_cast <gcall *> (stmt))
if (gimple_call_internal_p (call))
mem_type = get_mem_type_for_internal_fn (call, op_p);
if (mem_type)
{
iv = alloc_iv (data, iv->base, iv->step);
record_group_use (data, op_p, iv, stmt, USE_PTR_ADDRESS, mem_type);
return true;
}
return false;
}
/* Finds interesting uses of induction variables in the statement STMT. */
static void
find_interesting_uses_stmt (struct ivopts_data *data, gimple *stmt)
{
struct iv *iv;
tree op, *lhs, *rhs;
ssa_op_iter iter;
use_operand_p use_p;
enum tree_code code;
find_invariants_stmt (data, stmt);
if (gimple_code (stmt) == GIMPLE_COND)
{
find_interesting_uses_cond (data, stmt);
return;
}
if (is_gimple_assign (stmt))
{
lhs = gimple_assign_lhs_ptr (stmt);
rhs = gimple_assign_rhs1_ptr (stmt);
if (TREE_CODE (*lhs) == SSA_NAME)
{
/* If the statement defines an induction variable, the uses are not
interesting by themselves. */
iv = get_iv (data, *lhs);
if (iv && !integer_zerop (iv->step))
return;
}
code = gimple_assign_rhs_code (stmt);
if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
&& (REFERENCE_CLASS_P (*rhs)
|| is_gimple_val (*rhs)))
{
if (REFERENCE_CLASS_P (*rhs))
find_interesting_uses_address (data, stmt, rhs);
else
find_interesting_uses_op (data, *rhs);
if (REFERENCE_CLASS_P (*lhs))
find_interesting_uses_address (data, stmt, lhs);
return;
}
else if (TREE_CODE_CLASS (code) == tcc_comparison)
{
find_interesting_uses_cond (data, stmt);
return;
}
/* TODO -- we should also handle address uses of type
memory = call (whatever);
and
call (memory). */
}
if (gimple_code (stmt) == GIMPLE_PHI
&& gimple_bb (stmt) == data->current_loop->header)
{
iv = get_iv (data, PHI_RESULT (stmt));
if (iv && !integer_zerop (iv->step))
return;
}
FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE)
{
op = USE_FROM_PTR (use_p);
if (TREE_CODE (op) != SSA_NAME)
continue;
iv = get_iv (data, op);
if (!iv)
continue;
if (!find_address_like_use (data, stmt, use_p->use, iv))
find_interesting_uses_op (data, op);
}
}
/* Finds interesting uses of induction variables outside of loops
on loop exit edge EXIT. */
static void
find_interesting_uses_outside (struct ivopts_data *data, edge exit)
{
gphi *phi;
gphi_iterator psi;
tree def;
for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); gsi_next (&psi))
{
phi = psi.phi ();
def = PHI_ARG_DEF_FROM_EDGE (phi, exit);
if (!virtual_operand_p (def))
find_interesting_uses_op (data, def);
}
}
/* Return TRUE if OFFSET is within the range of [base + offset] addressing
mode for memory reference represented by USE. */
static GTY (()) vec<rtx, va_gc> *addr_list;
static bool
addr_offset_valid_p (struct iv_use *use, poly_int64 offset)
{
rtx reg, addr;
unsigned list_index;
addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (use->iv->base));
machine_mode addr_mode, mem_mode = TYPE_MODE (use->mem_type);
list_index = (unsigned) as * MAX_MACHINE_MODE + (unsigned) mem_mode;
if (list_index >= vec_safe_length (addr_list))
vec_safe_grow_cleared (addr_list, list_index + MAX_MACHINE_MODE, true);
addr = (*addr_list)[list_index];
if (!addr)
{
addr_mode = targetm.addr_space.address_mode (as);
reg = gen_raw_REG (addr_mode, LAST_VIRTUAL_REGISTER + 1);
addr = gen_rtx_fmt_ee (PLUS, addr_mode, reg, NULL_RTX);
(*addr_list)[list_index] = addr;
}
else
addr_mode = GET_MODE (addr);
XEXP (addr, 1) = gen_int_mode (offset, addr_mode);
return (memory_address_addr_space_p (mem_mode, addr, as));
}
/* Comparison function to sort group in ascending order of addr_offset. */
static int
group_compare_offset (const void *a, const void *b)
{
const struct iv_use *const *u1 = (const struct iv_use *const *) a;
const struct iv_use *const *u2 = (const struct iv_use *const *) b;
return compare_sizes_for_sort ((*u1)->addr_offset, (*u2)->addr_offset);
}
/* Check if small groups should be split. Return true if no group
contains more than two uses with distinct addr_offsets. Return
false otherwise. We want to split such groups because:
1) Small groups don't have much benefit and may interfer with
general candidate selection.
2) Size for problem with only small groups is usually small and
general algorithm can handle it well.
TODO -- Above claim may not hold when we want to merge memory
accesses with conseuctive addresses. */
static bool
split_small_address_groups_p (struct ivopts_data *data)
{
unsigned int i, j, distinct = 1;
struct iv_use *pre;
struct iv_group *group;
for (i = 0; i < data->vgroups.length (); i++)
{
group = data->vgroups[i];
if (group->vuses.length () == 1)
continue;
gcc_assert (address_p (group->type));
if (group->vuses.length () == 2)
{
if (compare_sizes_for_sort (group->vuses[0]->addr_offset,
group->vuses[1]->addr_offset) > 0)
std::swap (group->vuses[0], group->vuses[1]);
}
else
group->vuses.qsort (group_compare_offset);
if (distinct > 2)
continue;
distinct = 1;
for (pre = group->vuses[0], j = 1; j < group->vuses.length (); j++)
{
if (maybe_ne (group->vuses[j]->addr_offset, pre->addr_offset))
{
pre = group->vuses[j];
distinct++;
}
if (distinct > 2)
break;
}
}
return (distinct <= 2);
}
/* For each group of address type uses, this function further groups
these uses according to the maximum offset supported by target's
[base + offset] addressing mode. */
static void
split_address_groups (struct ivopts_data *data)
{
unsigned int i, j;
/* Always split group. */
bool split_p = split_small_address_groups_p (data);
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *new_group = NULL;
struct iv_group *group = data->vgroups[i];
struct iv_use *use = group->vuses[0];
use->id = 0;
use->group_id = group->id;
if (group->vuses.length () == 1)
continue;
gcc_assert (address_p (use->type));
for (j = 1; j < group->vuses.length ();)
{
struct iv_use *next = group->vuses[j];
poly_int64 offset = next->addr_offset - use->addr_offset;
/* Split group if aksed to, or the offset against the first
use can't fit in offset part of addressing mode. IV uses
having the same offset are still kept in one group. */
if (maybe_ne (offset, 0)
&& (split_p || !addr_offset_valid_p (use, offset)))
{
if (!new_group)
new_group = record_group (data, group->type);
group->vuses.ordered_remove (j);
new_group->vuses.safe_push (next);
continue;
}
next->id = j;
next->group_id = group->id;
j++;
}
}
}
/* Finds uses of the induction variables that are interesting. */
static void
find_interesting_uses (struct ivopts_data *data, basic_block *body)
{
basic_block bb;
gimple_stmt_iterator bsi;
unsigned i;
edge e;
for (i = 0; i < data->current_loop->num_nodes; i++)
{
edge_iterator ei;
bb = body[i];
FOR_EACH_EDGE (e, ei, bb->succs)
if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
&& !flow_bb_inside_loop_p (data->current_loop, e->dest))
find_interesting_uses_outside (data, e);
for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
find_interesting_uses_stmt (data, gsi_stmt (bsi));
for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
if (!is_gimple_debug (gsi_stmt (bsi)))
find_interesting_uses_stmt (data, gsi_stmt (bsi));
}
split_address_groups (data);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\n<IV Groups>:\n");
dump_groups (dump_file, data);
fprintf (dump_file, "\n");
}
}
/* Strips constant offsets from EXPR and stores them to OFFSET. If INSIDE_ADDR
is true, assume we are inside an address. If TOP_COMPREF is true, assume
we are at the top-level of the processed address. */
static tree
strip_offset_1 (tree expr, bool inside_addr, bool top_compref,
poly_int64 *offset)
{
tree op0 = NULL_TREE, op1 = NULL_TREE, tmp, step;
enum tree_code code;
tree type, orig_type = TREE_TYPE (expr);
poly_int64 off0, off1;
HOST_WIDE_INT st;
tree orig_expr = expr;
STRIP_NOPS (expr);
type = TREE_TYPE (expr);
code = TREE_CODE (expr);
*offset = 0;
switch (code)
{
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
op0 = TREE_OPERAND (expr, 0);
op1 = TREE_OPERAND (expr, 1);
op0 = strip_offset_1 (op0, false, false, &off0);
op1 = strip_offset_1 (op1, false, false, &off1);
*offset = (code == MINUS_EXPR ? off0 - off1 : off0 + off1);
if (op0 == TREE_OPERAND (expr, 0)
&& op1 == TREE_OPERAND (expr, 1))
return orig_expr;
if (integer_zerop (op1))
expr = op0;
else if (integer_zerop (op0))
{
if (code == MINUS_EXPR)
expr = fold_build1 (NEGATE_EXPR, type, op1);
else
expr = op1;
}
else
expr = fold_build2 (code, type, op0, op1);
return fold_convert (orig_type, expr);
case MULT_EXPR:
op1 = TREE_OPERAND (expr, 1);
if (!cst_and_fits_in_hwi (op1))
return orig_expr;
op0 = TREE_OPERAND (expr, 0);
op0 = strip_offset_1 (op0, false, false, &off0);
if (op0 == TREE_OPERAND (expr, 0))
return orig_expr;
*offset = off0 * int_cst_value (op1);
if (integer_zerop (op0))
expr = op0;
else
expr = fold_build2 (MULT_EXPR, type, op0, op1);
return fold_convert (orig_type, expr);
case ARRAY_REF:
case ARRAY_RANGE_REF:
if (!inside_addr)
return orig_expr;
step = array_ref_element_size (expr);
if (!cst_and_fits_in_hwi (step))
break;
st = int_cst_value (step);
op1 = TREE_OPERAND (expr, 1);
op1 = strip_offset_1 (op1, false, false, &off1);
*offset = off1 * st;
if (top_compref
&& integer_zerop (op1))
{
/* Strip the component reference completely. */
op0 = TREE_OPERAND (expr, 0);
op0 = strip_offset_1 (op0, inside_addr, top_compref, &off0);
*offset += off0;
return op0;
}
break;
case COMPONENT_REF:
{
tree field;
if (!inside_addr)
return orig_expr;
tmp = component_ref_field_offset (expr);
field = TREE_OPERAND (expr, 1);
if (top_compref
&& cst_and_fits_in_hwi (tmp)
&& cst_and_fits_in_hwi (DECL_FIELD_BIT_OFFSET (field)))
{
HOST_WIDE_INT boffset, abs_off;
/* Strip the component reference completely. */
op0 = TREE_OPERAND (expr, 0);
op0 = strip_offset_1 (op0, inside_addr, top_compref, &off0);
boffset = int_cst_value (DECL_FIELD_BIT_OFFSET (field));
abs_off = abs_hwi (boffset) / BITS_PER_UNIT;
if (boffset < 0)
abs_off = -abs_off;
*offset = off0 + int_cst_value (tmp) + abs_off;
return op0;
}
}
break;
case ADDR_EXPR:
op0 = TREE_OPERAND (expr, 0);
op0 = strip_offset_1 (op0, true, true, &off0);
*offset += off0;
if (op0 == TREE_OPERAND (expr, 0))
return orig_expr;
expr = build_fold_addr_expr (op0);
return fold_convert (orig_type, expr);
case MEM_REF:
/* ??? Offset operand? */
inside_addr = false;
break;
default:
if (ptrdiff_tree_p (expr, offset) && maybe_ne (*offset, 0))
return build_int_cst (orig_type, 0);
return orig_expr;
}
/* Default handling of expressions for that we want to recurse into
the first operand. */
op0 = TREE_OPERAND (expr, 0);
op0 = strip_offset_1 (op0, inside_addr, false, &off0);
*offset += off0;
if (op0 == TREE_OPERAND (expr, 0)
&& (!op1 || op1 == TREE_OPERAND (expr, 1)))
return orig_expr;
expr = copy_node (expr);
TREE_OPERAND (expr, 0) = op0;
if (op1)
TREE_OPERAND (expr, 1) = op1;
/* Inside address, we might strip the top level component references,
thus changing type of the expression. Handling of ADDR_EXPR
will fix that. */
expr = fold_convert (orig_type, expr);
return expr;
}
/* Strips constant offsets from EXPR and stores them to OFFSET. */
tree
strip_offset (tree expr, poly_uint64_pod *offset)
{
poly_int64 off;
tree core = strip_offset_1 (expr, false, false, &off);
*offset = off;
return core;
}
/* Returns variant of TYPE that can be used as base for different uses.
We return unsigned type with the same precision, which avoids problems
with overflows. */
static tree
generic_type_for (tree type)
{
if (POINTER_TYPE_P (type))
return unsigned_type_for (type);
if (TYPE_UNSIGNED (type))
return type;
return unsigned_type_for (type);
}
/* Private data for walk_tree. */
struct walk_tree_data
{
bitmap *inv_vars;
struct ivopts_data *idata;
};
/* Callback function for walk_tree, it records invariants and symbol
reference in *EXPR_P. DATA is the structure storing result info. */
static tree
find_inv_vars_cb (tree *expr_p, int *ws ATTRIBUTE_UNUSED, void *data)
{
tree op = *expr_p;
struct version_info *info;
struct walk_tree_data *wdata = (struct walk_tree_data*) data;
if (TREE_CODE (op) != SSA_NAME)
return NULL_TREE;
info = name_info (wdata->idata, op);
/* Because we expand simple operations when finding IVs, loop invariant
variable that isn't referred by the original loop could be used now.
Record such invariant variables here. */
if (!info->iv)
{
struct ivopts_data *idata = wdata->idata;
basic_block bb = gimple_bb (SSA_NAME_DEF_STMT (op));
if (!bb || !flow_bb_inside_loop_p (idata->current_loop, bb))
{
tree steptype = TREE_TYPE (op);
if (POINTER_TYPE_P (steptype))
steptype = sizetype;
set_iv (idata, op, op, build_int_cst (steptype, 0), true);
record_invariant (idata, op, false);
}
}
if (!info->inv_id || info->has_nonlin_use)
return NULL_TREE;
if (!*wdata->inv_vars)
*wdata->inv_vars = BITMAP_ALLOC (NULL);
bitmap_set_bit (*wdata->inv_vars, info->inv_id);
return NULL_TREE;
}
/* Records invariants in *EXPR_P. INV_VARS is the bitmap to that we should
store it. */
static inline void
find_inv_vars (struct ivopts_data *data, tree *expr_p, bitmap *inv_vars)
{
struct walk_tree_data wdata;
if (!inv_vars)
return;
wdata.idata = data;
wdata.inv_vars = inv_vars;
walk_tree (expr_p, find_inv_vars_cb, &wdata, NULL);
}
/* Get entry from invariant expr hash table for INV_EXPR. New entry
will be recorded if it doesn't exist yet. Given below two exprs:
inv_expr + cst1, inv_expr + cst2
It's hard to make decision whether constant part should be stripped
or not. We choose to not strip based on below facts:
1) We need to count ADD cost for constant part if it's stripped,
which isn't always trivial where this functions is called.
2) Stripping constant away may be conflict with following loop
invariant hoisting pass.
3) Not stripping constant away results in more invariant exprs,
which usually leads to decision preferring lower reg pressure. */
static iv_inv_expr_ent *
get_loop_invariant_expr (struct ivopts_data *data, tree inv_expr)
{
STRIP_NOPS (inv_expr);
if (poly_int_tree_p (inv_expr)
|| TREE_CODE (inv_expr) == SSA_NAME)
return NULL;
/* Don't strip constant part away as we used to. */
/* Stores EXPR in DATA->inv_expr_tab, return pointer to iv_inv_expr_ent. */
struct iv_inv_expr_ent ent;
ent.expr = inv_expr;
ent.hash = iterative_hash_expr (inv_expr, 0);
struct iv_inv_expr_ent **slot = data->inv_expr_tab->find_slot (&ent, INSERT);
if (!*slot)
{
*slot = XNEW (struct iv_inv_expr_ent);
(*slot)->expr = inv_expr;
(*slot)->hash = ent.hash;
(*slot)->id = ++data->max_inv_expr_id;
}
return *slot;
}
/* Return TRUE iff VAR is marked as maybe-undefined. See
mark_ssa_maybe_undefs. */
static inline bool
ssa_name_maybe_undef_p (tree var)
{
gcc_checking_assert (TREE_CODE (var) == SSA_NAME);
return TREE_VISITED (var);
}
/* Set (or clear, depending on VALUE) VAR's maybe-undefined mark. */
static inline void
ssa_name_set_maybe_undef (tree var, bool value = true)
{
gcc_checking_assert (TREE_CODE (var) == SSA_NAME);
TREE_VISITED (var) = value;
}
/* Return TRUE iff there are any non-PHI uses of VAR that dominate the
end of BB. If we return TRUE and BB is a loop header, then VAR we
be assumed to be defined within the loop, even if it is marked as
maybe-undefined. */
static inline bool
ssa_name_any_use_dominates_bb_p (tree var, basic_block bb)
{
imm_use_iterator iter;
use_operand_p use_p;
FOR_EACH_IMM_USE_FAST (use_p, iter, var)
{
if (is_a <gphi *> (USE_STMT (use_p))
|| is_gimple_debug (USE_STMT (use_p)))
continue;
basic_block dombb = gimple_bb (USE_STMT (use_p));
if (dominated_by_p (CDI_DOMINATORS, bb, dombb))
return true;
}
return false;
}
/* Mark as maybe_undef any SSA_NAMEs that are unsuitable as ivopts
candidates for potentially involving undefined behavior. */
static void
mark_ssa_maybe_undefs (void)
{
auto_vec<tree> queue;
/* Scan all SSA_NAMEs, marking the definitely-undefined ones as
maybe-undefined and queuing them for propagation, while clearing
the mark on others. */
unsigned int i;
tree var;
FOR_EACH_SSA_NAME (i, var, cfun)
{
if (SSA_NAME_IS_VIRTUAL_OPERAND (var)
|| !ssa_undefined_value_p (var, false))
ssa_name_set_maybe_undef (var, false);
else
{
ssa_name_set_maybe_undef (var);
queue.safe_push (var);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "marking _%i as maybe-undef\n",
SSA_NAME_VERSION (var));
}
}
/* Now propagate maybe-undefined from a DEF to any other PHI that
uses it, as long as there isn't any intervening use of DEF. */
while (!queue.is_empty ())
{
var = queue.pop ();
imm_use_iterator iter;
use_operand_p use_p;
FOR_EACH_IMM_USE_FAST (use_p, iter, var)
{
/* Any uses of VAR that aren't PHI args imply VAR must be
defined, otherwise undefined behavior would have been
definitely invoked. Only PHI args may hold
maybe-undefined values without invoking undefined
behavior for that reason alone. */
if (!is_a <gphi *> (USE_STMT (use_p)))
continue;
gphi *phi = as_a <gphi *> (USE_STMT (use_p));
tree def = gimple_phi_result (phi);
if (ssa_name_maybe_undef_p (def))
continue;
/* Look for any uses of the maybe-unused SSA_NAME that
dominates the block that reaches the incoming block
corresponding to the PHI arg in which it is mentioned.
That means we can assume the SSA_NAME is defined in that
path, so we only mark a PHI result as maybe-undef if we
find an unused reaching SSA_NAME. */
int idx = phi_arg_index_from_use (use_p);
basic_block bb = gimple_phi_arg_edge (phi, idx)->src;
if (ssa_name_any_use_dominates_bb_p (var, bb))
continue;
ssa_name_set_maybe_undef (def);
queue.safe_push (def);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "marking _%i as maybe-undef because of _%i\n",
SSA_NAME_VERSION (def), SSA_NAME_VERSION (var));
}
}
}
/* Return *TP if it is an SSA_NAME marked with TREE_VISITED, i.e., as
unsuitable as ivopts candidates for potentially involving undefined
behavior. */
static tree
find_ssa_undef (tree *tp, int *walk_subtrees, void *bb_)
{
basic_block bb = (basic_block) bb_;
if (TREE_CODE (*tp) == SSA_NAME
&& ssa_name_maybe_undef_p (*tp)
&& !ssa_name_any_use_dominates_bb_p (*tp, bb))
return *tp;
if (!EXPR_P (*tp))
*walk_subtrees = 0;
return NULL;
}
/* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and
position to POS. If USE is not NULL, the candidate is set as related to
it. If both BASE and STEP are NULL, we add a pseudocandidate for the
replacement of the final value of the iv by a direct computation. */
static struct iv_cand *
add_candidate_1 (struct ivopts_data *data, tree base, tree step, bool important,
enum iv_position pos, struct iv_use *use,
gimple *incremented_at, struct iv *orig_iv = NULL,
bool doloop = false)
{
unsigned i;
struct iv_cand *cand = NULL;
tree type, orig_type;
gcc_assert (base && step);
/* -fkeep-gc-roots-live means that we have to keep a real pointer
live, but the ivopts code may replace a real pointer with one
pointing before or after the memory block that is then adjusted
into the memory block during the loop. FIXME: It would likely be
better to actually force the pointer live and still use ivopts;
for example, it would be enough to write the pointer into memory
and keep it there until after the loop. */
if (flag_keep_gc_roots_live && POINTER_TYPE_P (TREE_TYPE (base)))
return NULL;
/* If BASE contains undefined SSA names make sure we only record
the original IV. */
bool involves_undefs = false;
if (walk_tree (&base, find_ssa_undef, data->current_loop->header, NULL))
{
if (pos != IP_ORIGINAL)
return NULL;
important = false;
involves_undefs = true;
}
/* For non-original variables, make sure their values are computed in a type
that does not invoke undefined behavior on overflows (since in general,
we cannot prove that these induction variables are non-wrapping). */
if (pos != IP_ORIGINAL)
{
orig_type = TREE_TYPE (base);
type = generic_type_for (orig_type);
if (type != orig_type)
{
base = fold_convert (type, base);
step = fold_convert (type, step);
}
}
for (i = 0; i < data->vcands.length (); i++)
{
cand = data->vcands[i];
if (cand->pos != pos)
continue;
if (cand->incremented_at != incremented_at
|| ((pos == IP_AFTER_USE || pos == IP_BEFORE_USE)
&& cand->ainc_use != use))
continue;
if (operand_equal_p (base, cand->iv->base, 0)
&& operand_equal_p (step, cand->iv->step, 0)
&& (TYPE_PRECISION (TREE_TYPE (base))
== TYPE_PRECISION (TREE_TYPE (cand->iv->base))))
break;
}
if (i == data->vcands.length ())
{
cand = XCNEW (struct iv_cand);
cand->id = i;
cand->iv = alloc_iv (data, base, step);
cand->pos = pos;
if (pos != IP_ORIGINAL)
{
if (doloop)
cand->var_before = create_tmp_var_raw (TREE_TYPE (base), "doloop");
else
cand->var_before = create_tmp_var_raw (TREE_TYPE (base), "ivtmp");
cand->var_after = cand->var_before;
}
cand->important = important;
cand->involves_undefs = involves_undefs;
cand->incremented_at = incremented_at;
cand->doloop_p = doloop;
data->vcands.safe_push (cand);
if (!poly_int_tree_p (step))
{
find_inv_vars (data, &step, &cand->inv_vars);
iv_inv_expr_ent *inv_expr = get_loop_invariant_expr (data, step);
/* Share bitmap between inv_vars and inv_exprs for cand. */
if (inv_expr != NULL)
{
cand->inv_exprs = cand->inv_vars;
cand->inv_vars = NULL;
if (cand->inv_exprs)
bitmap_clear (cand->inv_exprs);
else
cand->inv_exprs = BITMAP_ALLOC (NULL);
bitmap_set_bit (cand->inv_exprs, inv_expr->id);
}
}
if (pos == IP_AFTER_USE || pos == IP_BEFORE_USE)
cand->ainc_use = use;
else
cand->ainc_use = NULL;
cand->orig_iv = orig_iv;
if (dump_file && (dump_flags & TDF_DETAILS))
dump_cand (dump_file, cand);
}
cand->important |= important;
cand->doloop_p |= doloop;
/* Relate candidate to the group for which it is added. */
if (use)
bitmap_set_bit (data->vgroups[use->group_id]->related_cands, i);
return cand;
}
/* Returns true if incrementing the induction variable at the end of the LOOP
is allowed.
The purpose is to avoid splitting latch edge with a biv increment, thus
creating a jump, possibly confusing other optimization passes and leaving
less freedom to scheduler. So we allow IP_END only if IP_NORMAL is not
available (so we do not have a better alternative), or if the latch edge
is already nonempty. */
static bool
allow_ip_end_pos_p (class loop *loop)
{
if (!ip_normal_pos (loop))
return true;
if (!empty_block_p (ip_end_pos (loop)))
return true;
return false;
}
/* If possible, adds autoincrement candidates BASE + STEP * i based on use USE.
Important field is set to IMPORTANT. */
static void
add_autoinc_candidates (struct ivopts_data *data, tree base, tree step,
bool important, struct iv_use *use)
{
basic_block use_bb = gimple_bb (use->stmt);
machine_mode mem_mode;
unsigned HOST_WIDE_INT cstepi;
/* If we insert the increment in any position other than the standard
ones, we must ensure that it is incremented once per iteration.
It must not be in an inner nested loop, or one side of an if
statement. */
if (use_bb->loop_father != data->current_loop
|| !dominated_by_p (CDI_DOMINATORS, data->current_loop->latch, use_bb)
|| stmt_can_throw_internal (cfun, use->stmt)
|| !cst_and_fits_in_hwi (step))
return;
cstepi = int_cst_value (step);
mem_mode = TYPE_MODE (use->mem_type);
if (((USE_LOAD_PRE_INCREMENT (mem_mode)
|| USE_STORE_PRE_INCREMENT (mem_mode))
&& known_eq (GET_MODE_SIZE (mem_mode), cstepi))
|| ((USE_LOAD_PRE_DECREMENT (mem_mode)
|| USE_STORE_PRE_DECREMENT (mem_mode))
&& known_eq (GET_MODE_SIZE (mem_mode), -cstepi)))
{
enum tree_code code = MINUS_EXPR;
tree new_base;
tree new_step = step;
if (POINTER_TYPE_P (TREE_TYPE (base)))
{
new_step = fold_build1 (NEGATE_EXPR, TREE_TYPE (step), step);
code = POINTER_PLUS_EXPR;
}
else
new_step = fold_convert (TREE_TYPE (base), new_step);
new_base = fold_build2 (code, TREE_TYPE (base), base, new_step);
add_candidate_1 (data, new_base, step, important, IP_BEFORE_USE, use,
use->stmt);
}
if (((USE_LOAD_POST_INCREMENT (mem_mode)
|| USE_STORE_POST_INCREMENT (mem_mode))
&& known_eq (GET_MODE_SIZE (mem_mode), cstepi))
|| ((USE_LOAD_POST_DECREMENT (mem_mode)
|| USE_STORE_POST_DECREMENT (mem_mode))
&& known_eq (GET_MODE_SIZE (mem_mode), -cstepi)))
{
add_candidate_1 (data, base, step, important, IP_AFTER_USE, use,
use->stmt);
}
}
/* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and
position to POS. If USE is not NULL, the candidate is set as related to
it. The candidate computation is scheduled before exit condition and at
the end of loop. */
static void
add_candidate (struct ivopts_data *data, tree base, tree step, bool important,
struct iv_use *use, struct iv *orig_iv = NULL,
bool doloop = false)
{
if (ip_normal_pos (data->current_loop))
add_candidate_1 (data, base, step, important, IP_NORMAL, use, NULL, orig_iv,
doloop);
/* Exclude doloop candidate here since it requires decrement then comparison
and jump, the IP_END position doesn't match. */
if (!doloop && ip_end_pos (data->current_loop)
&& allow_ip_end_pos_p (data->current_loop))
add_candidate_1 (data, base, step, important, IP_END, use, NULL, orig_iv);
}
/* Adds standard iv candidates. */
static void
add_standard_iv_candidates (struct ivopts_data *data)
{
add_candidate (data, integer_zero_node, integer_one_node, true, NULL);
/* The same for a double-integer type if it is still fast enough. */
if (TYPE_PRECISION
(long_integer_type_node) > TYPE_PRECISION (integer_type_node)
&& TYPE_PRECISION (long_integer_type_node) <= BITS_PER_WORD)
add_candidate (data, build_int_cst (long_integer_type_node, 0),
build_int_cst (long_integer_type_node, 1), true, NULL);
/* The same for a double-integer type if it is still fast enough. */
if (TYPE_PRECISION
(long_long_integer_type_node) > TYPE_PRECISION (long_integer_type_node)
&& TYPE_PRECISION (long_long_integer_type_node) <= BITS_PER_WORD)
add_candidate (data, build_int_cst (long_long_integer_type_node, 0),
build_int_cst (long_long_integer_type_node, 1), true, NULL);
}
/* Adds candidates bases on the old induction variable IV. */
static void
add_iv_candidate_for_biv (struct ivopts_data *data, struct iv *iv)
{
gimple *phi;
tree def;
struct iv_cand *cand;
/* Check if this biv is used in address type use. */
if (iv->no_overflow && iv->have_address_use
&& INTEGRAL_TYPE_P (TREE_TYPE (iv->base))
&& TYPE_PRECISION (TREE_TYPE (iv->base)) < TYPE_PRECISION (sizetype))
{
tree base = fold_convert (sizetype, iv->base);
tree step = fold_convert (sizetype, iv->step);
/* Add iv cand of same precision as index part in TARGET_MEM_REF. */
add_candidate (data, base, step, true, NULL, iv);
/* Add iv cand of the original type only if it has nonlinear use. */
if (iv->nonlin_use)
add_candidate (data, iv->base, iv->step, true, NULL);
}
else
add_candidate (data, iv->base, iv->step, true, NULL);
/* The same, but with initial value zero. */
if (POINTER_TYPE_P (TREE_TYPE (iv->base)))
add_candidate (data, size_int (0), iv->step, true, NULL);
else
add_candidate (data, build_int_cst (TREE_TYPE (iv->base), 0),
iv->step, true, NULL);
phi = SSA_NAME_DEF_STMT (iv->ssa_name);
if (gimple_code (phi) == GIMPLE_PHI)
{
/* Additionally record the possibility of leaving the original iv
untouched. */
def = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (data->current_loop));
/* Don't add candidate if it's from another PHI node because
it's an affine iv appearing in the form of PEELED_CHREC. */
phi = SSA_NAME_DEF_STMT (def);
if (gimple_code (phi) != GIMPLE_PHI)
{
cand = add_candidate_1 (data,
iv->base, iv->step, true, IP_ORIGINAL, NULL,
SSA_NAME_DEF_STMT (def));
if (cand)
{
cand->var_before = iv->ssa_name;
cand->var_after = def;
}
}
else
gcc_assert (gimple_bb (phi) == data->current_loop->header);
}
}
/* Adds candidates based on the old induction variables. */
static void
add_iv_candidate_for_bivs (struct ivopts_data *data)
{
unsigned i;
struct iv *iv;
bitmap_iterator bi;
EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
{
iv = ver_info (data, i)->iv;
if (iv && iv->biv_p && !integer_zerop (iv->step))
add_iv_candidate_for_biv (data, iv);
}
}
/* Record common candidate {BASE, STEP} derived from USE in hashtable. */
static void
record_common_cand (struct ivopts_data *data, tree base,
tree step, struct iv_use *use)
{
class iv_common_cand ent;
class iv_common_cand **slot;
ent.base = base;
ent.step = step;
ent.hash = iterative_hash_expr (base, 0);
ent.hash = iterative_hash_expr (step, ent.hash);
slot = data->iv_common_cand_tab->find_slot (&ent, INSERT);
if (*slot == NULL)
{
*slot = new iv_common_cand ();
(*slot)->base = base;
(*slot)->step = step;
(*slot)->uses.create (8);
(*slot)->hash = ent.hash;
data->iv_common_cands.safe_push ((*slot));
}
gcc_assert (use != NULL);
(*slot)->uses.safe_push (use);
return;
}
/* Comparison function used to sort common candidates. */
static int
common_cand_cmp (const void *p1, const void *p2)
{
unsigned n1, n2;
const class iv_common_cand *const *const ccand1
= (const class iv_common_cand *const *)p1;
const class iv_common_cand *const *const ccand2
= (const class iv_common_cand *const *)p2;
n1 = (*ccand1)->uses.length ();
n2 = (*ccand2)->uses.length ();
return n2 - n1;
}
/* Adds IV candidates based on common candidated recorded. */
static void
add_iv_candidate_derived_from_uses (struct ivopts_data *data)
{
unsigned i, j;
struct iv_cand *cand_1, *cand_2;
data->iv_common_cands.qsort (common_cand_cmp);
for (i = 0; i < data->iv_common_cands.length (); i++)
{
class iv_common_cand *ptr = data->iv_common_cands[i];
/* Only add IV candidate if it's derived from multiple uses. */
if (ptr->uses.length () <= 1)
break;
cand_1 = NULL;
cand_2 = NULL;
if (ip_normal_pos (data->current_loop))
cand_1 = add_candidate_1 (data, ptr->base, ptr->step,
false, IP_NORMAL, NULL, NULL);
if (ip_end_pos (data->current_loop)
&& allow_ip_end_pos_p (data->current_loop))
cand_2 = add_candidate_1 (data, ptr->base, ptr->step,
false, IP_END, NULL, NULL);
/* Bind deriving uses and the new candidates. */
for (j = 0; j < ptr->uses.length (); j++)
{
struct iv_group *group = data->vgroups[ptr->uses[j]->group_id];
if (cand_1)
bitmap_set_bit (group->related_cands, cand_1->id);
if (cand_2)
bitmap_set_bit (group->related_cands, cand_2->id);
}
}
/* Release data since it is useless from this point. */
data->iv_common_cand_tab->empty ();
data->iv_common_cands.truncate (0);
}
/* Adds candidates based on the value of USE's iv. */
static void
add_iv_candidate_for_use (struct ivopts_data *data, struct iv_use *use)
{
poly_uint64 offset;
tree base;
struct iv *iv = use->iv;
tree basetype = TREE_TYPE (iv->base);
/* Don't add candidate for iv_use with non integer, pointer or non-mode
precision types, instead, add candidate for the corresponding scev in
unsigned type with the same precision. See PR93674 for more info. */
if ((TREE_CODE (basetype) != INTEGER_TYPE && !POINTER_TYPE_P (basetype))
|| !type_has_mode_precision_p (basetype))
{
basetype = lang_hooks.types.type_for_mode (TYPE_MODE (basetype),
TYPE_UNSIGNED (basetype));
add_candidate (data, fold_convert (basetype, iv->base),
fold_convert (basetype, iv->step), false, NULL);
return;
}
add_candidate (data, iv->base, iv->step, false, use);
/* Record common candidate for use in case it can be shared by others. */
record_common_cand (data, iv->base, iv->step, use);
/* Record common candidate with initial value zero. */
basetype = TREE_TYPE (iv->base);
if (POINTER_TYPE_P (basetype))
basetype = sizetype;
record_common_cand (data, build_int_cst (basetype, 0), iv->step, use);
/* Compare the cost of an address with an unscaled index with the cost of
an address with a scaled index and add candidate if useful. */
poly_int64 step;
if (use != NULL
&& poly_int_tree_p (iv->step, &step)
&& address_p (use->type))
{
poly_int64 new_step;
unsigned int fact = preferred_mem_scale_factor
(use->iv->base,
TYPE_MODE (use->mem_type),
optimize_loop_for_speed_p (data->current_loop));
if (fact != 1
&& multiple_p (step, fact, &new_step))
add_candidate (data, size_int (0),
wide_int_to_tree (sizetype, new_step),
true, NULL);
}
/* Record common candidate with constant offset stripped in base.
Like the use itself, we also add candidate directly for it. */
base = strip_offset (iv->base, &offset);
if (maybe_ne (offset, 0U) || base != iv->base)
{
record_common_cand (data, base, iv->step, use);
add_candidate (data, base, iv->step, false, use);
}
/* Record common candidate with base_object removed in base. */
base = iv->base;
STRIP_NOPS (base);
if (iv->base_object != NULL && TREE_CODE (base) == POINTER_PLUS_EXPR)
{
tree step = iv->step;
STRIP_NOPS (step);
base = TREE_OPERAND (base, 1);
step = fold_convert (sizetype, step);
record_common_cand (data, base, step, use);
/* Also record common candidate with offset stripped. */
base = strip_offset (base, &offset);
if (maybe_ne (offset, 0U))
record_common_cand (data, base, step, use);
}
/* At last, add auto-incremental candidates. Make such variables
important since other iv uses with same base object may be based
on it. */
if (use != NULL && address_p (use->type))
add_autoinc_candidates (data, iv->base, iv->step, true, use);
}
/* Adds candidates based on the uses. */
static void
add_iv_candidate_for_groups (struct ivopts_data *data)
{
unsigned i;
/* Only add candidate for the first use in group. */
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
gcc_assert (group->vuses[0] != NULL);
add_iv_candidate_for_use (data, group->vuses[0]);
}
add_iv_candidate_derived_from_uses (data);
}
/* Record important candidates and add them to related_cands bitmaps. */
static void
record_important_candidates (struct ivopts_data *data)
{
unsigned i;
struct iv_group *group;
for (i = 0; i < data->vcands.length (); i++)
{
struct iv_cand *cand = data->vcands[i];
if (cand->important)
bitmap_set_bit (data->important_candidates, i);
}
data->consider_all_candidates = (data->vcands.length ()
<= CONSIDER_ALL_CANDIDATES_BOUND);
/* Add important candidates to groups' related_cands bitmaps. */
for (i = 0; i < data->vgroups.length (); i++)
{
group = data->vgroups[i];
bitmap_ior_into (group->related_cands, data->important_candidates);
}
}
/* Allocates the data structure mapping the (use, candidate) pairs to costs.
If consider_all_candidates is true, we use a two-dimensional array, otherwise
we allocate a simple list to every use. */
static void
alloc_use_cost_map (struct ivopts_data *data)
{
unsigned i, size, s;
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
if (data->consider_all_candidates)
size = data->vcands.length ();
else
{
s = bitmap_count_bits (group->related_cands);
/* Round up to the power of two, so that moduling by it is fast. */
size = s ? (1 << ceil_log2 (s)) : 1;
}
group->n_map_members = size;
group->cost_map = XCNEWVEC (class cost_pair, size);
}
}
/* Sets cost of (GROUP, CAND) pair to COST and record that it depends
on invariants INV_VARS and that the value used in expressing it is
VALUE, and in case of iv elimination the comparison operator is COMP. */
static void
set_group_iv_cost (struct ivopts_data *data,
struct iv_group *group, struct iv_cand *cand,
comp_cost cost, bitmap inv_vars, tree value,
enum tree_code comp, bitmap inv_exprs)
{
unsigned i, s;
if (cost.infinite_cost_p ())
{
BITMAP_FREE (inv_vars);
BITMAP_FREE (inv_exprs);
return;
}
if (data->consider_all_candidates)
{
group->cost_map[cand->id].cand = cand;
group->cost_map[cand->id].cost = cost;
group->cost_map[cand->id].inv_vars = inv_vars;
group->cost_map[cand->id].inv_exprs = inv_exprs;
group->cost_map[cand->id].value = value;
group->cost_map[cand->id].comp = comp;
return;
}
/* n_map_members is a power of two, so this computes modulo. */
s = cand->id & (group->n_map_members - 1);
for (i = s; i < group->n_map_members; i++)
if (!group->cost_map[i].cand)
goto found;
for (i = 0; i < s; i++)
if (!group->cost_map[i].cand)
goto found;
gcc_unreachable ();
found:
group->cost_map[i].cand = cand;
group->cost_map[i].cost = cost;
group->cost_map[i].inv_vars = inv_vars;
group->cost_map[i].inv_exprs = inv_exprs;
group->cost_map[i].value = value;
group->cost_map[i].comp = comp;
}
/* Gets cost of (GROUP, CAND) pair. */
static class cost_pair *
get_group_iv_cost (struct ivopts_data *data, struct iv_group *group,
struct iv_cand *cand)
{
unsigned i, s;
class cost_pair *ret;
if (!cand)
return NULL;
if (data->consider_all_candidates)
{
ret = group->cost_map + cand->id;
if (!ret->cand)
return NULL;
return ret;
}
/* n_map_members is a power of two, so this computes modulo. */
s = cand->id & (group->n_map_members - 1);
for (i = s; i < group->n_map_members; i++)
if (group->cost_map[i].cand == cand)
return group->cost_map + i;
else if (group->cost_map[i].cand == NULL)
return NULL;
for (i = 0; i < s; i++)
if (group->cost_map[i].cand == cand)
return group->cost_map + i;
else if (group->cost_map[i].cand == NULL)
return NULL;
return NULL;
}
/* Produce DECL_RTL for object obj so it looks like it is stored in memory. */
static rtx
produce_memory_decl_rtl (tree obj, int *regno)
{
addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (obj));
machine_mode address_mode = targetm.addr_space.address_mode (as);
rtx x;
gcc_assert (obj);
if (TREE_STATIC (obj) || DECL_EXTERNAL (obj))
{
const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (obj));
x = gen_rtx_SYMBOL_REF (address_mode, name);
SET_SYMBOL_REF_DECL (x, obj);
x = gen_rtx_MEM (DECL_MODE (obj), x);
set_mem_addr_space (x, as);
targetm.encode_section_info (obj, x, true);
}
else
{
x = gen_raw_REG (address_mode, (*regno)++);
x = gen_rtx_MEM (DECL_MODE (obj), x);
set_mem_addr_space (x, as);
}
return x;
}
/* Prepares decl_rtl for variables referred in *EXPR_P. Callback for
walk_tree. DATA contains the actual fake register number. */
static tree
prepare_decl_rtl (tree *expr_p, int *ws, void *data)
{
tree obj = NULL_TREE;
rtx x = NULL_RTX;
int *regno = (int *) data;
switch (TREE_CODE (*expr_p))
{
case ADDR_EXPR:
for (expr_p = &TREE_OPERAND (*expr_p, 0);
handled_component_p (*expr_p);
expr_p = &TREE_OPERAND (*expr_p, 0))
continue;
obj = *expr_p;
if (DECL_P (obj) && HAS_RTL_P (obj) && !DECL_RTL_SET_P (obj))
x = produce_memory_decl_rtl (obj, regno);
break;
case SSA_NAME:
*ws = 0;
obj = SSA_NAME_VAR (*expr_p);
/* Defer handling of anonymous SSA_NAMEs to the expander. */
if (!obj)
return NULL_TREE;
if (!DECL_RTL_SET_P (obj))
x = gen_raw_REG (DECL_MODE (obj), (*regno)++);
break;
case VAR_DECL:
case PARM_DECL:
case RESULT_DECL:
*ws = 0;
obj = *expr_p;
if (DECL_RTL_SET_P (obj))
break;
if (DECL_MODE (obj) == BLKmode)
x = produce_memory_decl_rtl (obj, regno);
else
x = gen_raw_REG (DECL_MODE (obj), (*regno)++);
break;
default:
break;
}
if (x)
{
decl_rtl_to_reset.safe_push (obj);
SET_DECL_RTL (obj, x);
}
return NULL_TREE;
}
/* Predict whether the given loop will be transformed in the RTL
doloop_optimize pass. Attempt to duplicate some doloop_optimize checks.
This is only for target independent checks, see targetm.predict_doloop_p
for the target dependent ones.
Note that according to some initial investigation, some checks like costly
niter check and invalid stmt scanning don't have much gains among general
cases, so keep this as simple as possible first.
Some RTL specific checks seems unable to be checked in gimple, if any new
checks or easy checks _are_ missing here, please add them. */
static bool
generic_predict_doloop_p (struct ivopts_data *data)
{
class loop *loop = data->current_loop;
/* Call target hook for target dependent checks. */
if (!targetm.predict_doloop_p (loop))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Predict doloop failure due to"
" target specific checks.\n");
return false;
}
/* Similar to doloop_optimize, check iteration description to know it's
suitable or not. Keep it as simple as possible, feel free to extend it
if you find any multiple exits cases matter. */
edge exit = single_dom_exit (loop);
class tree_niter_desc *niter_desc;
if (!exit || !(niter_desc = niter_for_exit (data, exit)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Predict doloop failure due to"
" unexpected niters.\n");
return false;
}
/* Similar to doloop_optimize, check whether iteration count too small
and not profitable. */
HOST_WIDE_INT est_niter = get_estimated_loop_iterations_int (loop);
if (est_niter == -1)
est_niter = get_likely_max_loop_iterations_int (loop);
if (est_niter >= 0 && est_niter < 3)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Predict doloop failure due to"
" too few iterations (%u).\n",
(unsigned int) est_niter);
return false;
}
return true;
}
/* Determines cost of the computation of EXPR. */
static unsigned
computation_cost (tree expr, bool speed)
{
rtx_insn *seq;
rtx rslt;
tree type = TREE_TYPE (expr);
unsigned cost;
/* Avoid using hard regs in ways which may be unsupported. */
int regno = LAST_VIRTUAL_REGISTER + 1;
struct cgraph_node *node = cgraph_node::get (current_function_decl);
enum node_frequency real_frequency = node->frequency;
node->frequency = NODE_FREQUENCY_NORMAL;
crtl->maybe_hot_insn_p = speed;
walk_tree (&expr, prepare_decl_rtl, &regno, NULL);
start_sequence ();
rslt = expand_expr (expr, NULL_RTX, TYPE_MODE (type), EXPAND_NORMAL);
seq = get_insns ();
end_sequence ();
default_rtl_profile ();
node->frequency = real_frequency;
cost = seq_cost (seq, speed);
if (MEM_P (rslt))
cost += address_cost (XEXP (rslt, 0), TYPE_MODE (type),
TYPE_ADDR_SPACE (type), speed);
else if (!REG_P (rslt))
cost += set_src_cost (rslt, TYPE_MODE (type), speed);
return cost;
}
/* Returns variable containing the value of candidate CAND at statement AT. */
static tree
var_at_stmt (class loop *loop, struct iv_cand *cand, gimple *stmt)
{
if (stmt_after_increment (loop, cand, stmt))
return cand->var_after;
else
return cand->var_before;
}
/* If A is (TYPE) BA and B is (TYPE) BB, and the types of BA and BB have the
same precision that is at least as wide as the precision of TYPE, stores
BA to A and BB to B, and returns the type of BA. Otherwise, returns the
type of A and B. */
static tree
determine_common_wider_type (tree *a, tree *b)
{
tree wider_type = NULL;
tree suba, subb;
tree atype = TREE_TYPE (*a);
if (CONVERT_EXPR_P (*a))
{
suba = TREE_OPERAND (*a, 0);
wider_type = TREE_TYPE (suba);
if (TYPE_PRECISION (wider_type) < TYPE_PRECISION (atype))
return atype;
}
else
return atype;
if (CONVERT_EXPR_P (*b))
{
subb = TREE_OPERAND (*b, 0);
if (TYPE_PRECISION (wider_type) != TYPE_PRECISION (TREE_TYPE (subb)))
return atype;
}
else
return atype;
*a = suba;
*b = subb;
return wider_type;
}
/* Determines the expression by that USE is expressed from induction variable
CAND at statement AT in LOOP. The expression is stored in two parts in a
decomposed form. The invariant part is stored in AFF_INV; while variant
part in AFF_VAR. Store ratio of CAND.step over USE.step in PRAT if it's
non-null. Returns false if USE cannot be expressed using CAND. */
static bool
get_computation_aff_1 (class loop *loop, gimple *at, struct iv_use *use,
struct iv_cand *cand, class aff_tree *aff_inv,
class aff_tree *aff_var, widest_int *prat = NULL)
{
tree ubase = use->iv->base, ustep = use->iv->step;
tree cbase = cand->iv->base, cstep = cand->iv->step;
tree common_type, uutype, var, cstep_common;
tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase);
aff_tree aff_cbase;
widest_int rat;
/* We must have a precision to express the values of use. */
if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype))
return false;
var = var_at_stmt (loop, cand, at);
uutype = unsigned_type_for (utype);
/* If the conversion is not noop, perform it. */
if (TYPE_PRECISION (utype) < TYPE_PRECISION (ctype))
{
if (cand->orig_iv != NULL && CONVERT_EXPR_P (cbase)
&& (CONVERT_EXPR_P (cstep) || poly_int_tree_p (cstep)))
{
tree inner_base, inner_step, inner_type;
inner_base = TREE_OPERAND (cbase, 0);
if (CONVERT_EXPR_P (cstep))
inner_step = TREE_OPERAND (cstep, 0);
else
inner_step = cstep;
inner_type = TREE_TYPE (inner_base);
/* If candidate is added from a biv whose type is smaller than
ctype, we know both candidate and the biv won't overflow.
In this case, it's safe to skip the convertion in candidate.
As an example, (unsigned short)((unsigned long)A) equals to
(unsigned short)A, if A has a type no larger than short. */
if (TYPE_PRECISION (inner_type) <= TYPE_PRECISION (uutype))
{
cbase = inner_base;
cstep = inner_step;
}
}
cbase = fold_convert (uutype, cbase);
cstep = fold_convert (uutype, cstep);
var = fold_convert (uutype, var);
}
/* Ratio is 1 when computing the value of biv cand by itself.
We can't rely on constant_multiple_of in this case because the
use is created after the original biv is selected. The call
could fail because of inconsistent fold behavior. See PR68021
for more information. */
if (cand->pos == IP_ORIGINAL && cand->incremented_at == use->stmt)
{
gcc_assert (is_gimple_assign (use->stmt));
gcc_assert (use->iv->ssa_name == cand->var_after);
gcc_assert (gimple_assign_lhs (use->stmt) == cand->var_after);
rat = 1;
}
else if (!constant_multiple_of (ustep, cstep, &rat))
return false;
if (prat)
*prat = rat;
/* In case both UBASE and CBASE are shortened to UUTYPE from some common
type, we achieve better folding by computing their difference in this
wider type, and cast the result to UUTYPE. We do not need to worry about
overflows, as all the arithmetics will in the end be performed in UUTYPE
anyway. */
common_type = determine_common_wider_type (&ubase, &cbase);
/* use = ubase - ratio * cbase + ratio * var. */
tree_to_aff_combination (ubase, common_type, aff_inv);
tree_to_aff_combination (cbase, common_type, &aff_cbase);
tree_to_aff_combination (var, uutype, aff_var);
/* We need to shift the value if we are after the increment. */
if (stmt_after_increment (loop, cand, at))
{
aff_tree cstep_aff;
if (common_type != uutype)
cstep_common = fold_convert (common_type, cstep);
else
cstep_common = cstep;
tree_to_aff_combination (cstep_common, common_type, &cstep_aff);
aff_combination_add (&aff_cbase, &cstep_aff);
}
aff_combination_scale (&aff_cbase, -rat);
aff_combination_add (aff_inv, &aff_cbase);
if (common_type != uutype)
aff_combination_convert (aff_inv, uutype);
aff_combination_scale (aff_var, rat);
return true;
}
/* Determines the expression by that USE is expressed from induction variable
CAND at statement AT in LOOP. The expression is stored in a decomposed
form into AFF. Returns false if USE cannot be expressed using CAND. */
static bool
get_computation_aff (class loop *loop, gimple *at, struct iv_use *use,
struct iv_cand *cand, class aff_tree *aff)
{
aff_tree aff_var;
if (!get_computation_aff_1 (loop, at, use, cand, aff, &aff_var))
return false;
aff_combination_add (aff, &aff_var);
return true;
}
/* Return the type of USE. */
static tree
get_use_type (struct iv_use *use)
{
tree base_type = TREE_TYPE (use->iv->base);
tree type;
if (use->type == USE_REF_ADDRESS)
{
/* The base_type may be a void pointer. Create a pointer type based on
the mem_ref instead. */
type = build_pointer_type (TREE_TYPE (*use->op_p));
gcc_assert (TYPE_ADDR_SPACE (TREE_TYPE (type))
== TYPE_ADDR_SPACE (TREE_TYPE (base_type)));
}
else
type = base_type;
return type;
}
/* Determines the expression by that USE is expressed from induction variable
CAND at statement AT in LOOP. The computation is unshared. */
static tree
get_computation_at (class loop *loop, gimple *at,
struct iv_use *use, struct iv_cand *cand)
{
aff_tree aff;
tree type = get_use_type (use);
if (!get_computation_aff (loop, at, use, cand, &aff))
return NULL_TREE;
unshare_aff_combination (&aff);
return fold_convert (type, aff_combination_to_tree (&aff));
}
/* Like get_computation_at, but try harder, even if the computation
is more expensive. Intended for debug stmts. */
static tree
get_debug_computation_at (class loop *loop, gimple *at,
struct iv_use *use, struct iv_cand *cand)
{
if (tree ret = get_computation_at (loop, at, use, cand))
return ret;
tree ubase = use->iv->base, ustep = use->iv->step;
tree cbase = cand->iv->base, cstep = cand->iv->step;
tree var;
tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase);
widest_int rat;
/* We must have a precision to express the values of use. */
if (TYPE_PRECISION (utype) >= TYPE_PRECISION (ctype))
return NULL_TREE;
/* Try to handle the case that get_computation_at doesn't,
try to express
use = ubase + (var - cbase) / ratio. */
if (!constant_multiple_of (cstep, fold_convert (TREE_TYPE (cstep), ustep),
&rat))
return NULL_TREE;
bool neg_p = false;
if (wi::neg_p (rat))
{
if (TYPE_UNSIGNED (ctype))
return NULL_TREE;
neg_p = true;
rat = wi::neg (rat);
}
/* If both IVs can wrap around and CAND doesn't have a power of two step,
it is unsafe. Consider uint16_t CAND with step 9, when wrapping around,
the values will be ... 0xfff0, 0xfff9, 2, 11 ... and when use is say
uint8_t with step 3, those values divided by 3 cast to uint8_t will be
... 0x50, 0x53, 0, 3 ... rather than expected 0x50, 0x53, 0x56, 0x59. */
if (!use->iv->no_overflow
&& !cand->iv->no_overflow
&& !integer_pow2p (cstep))
return NULL_TREE;
int bits = wi::exact_log2 (rat);
if (bits == -1)
bits = wi::floor_log2 (rat) + 1;
if (!cand->iv->no_overflow
&& TYPE_PRECISION (utype) + bits > TYPE_PRECISION (ctype))
return NULL_TREE;
var = var_at_stmt (loop, cand, at);
if (POINTER_TYPE_P (ctype))
{
ctype = unsigned_type_for (ctype);
cbase = fold_convert (ctype, cbase);
cstep = fold_convert (ctype, cstep);
var = fold_convert (ctype, var);
}
if (stmt_after_increment (loop, cand, at))
var = fold_build2 (MINUS_EXPR, TREE_TYPE (var), var,
unshare_expr (cstep));
var = fold_build2 (MINUS_EXPR, TREE_TYPE (var), var, cbase);
var = fold_build2 (EXACT_DIV_EXPR, TREE_TYPE (var), var,
wide_int_to_tree (TREE_TYPE (var), rat));
if (POINTER_TYPE_P (utype))
{
var = fold_convert (sizetype, var);
if (neg_p)
var = fold_build1 (NEGATE_EXPR, sizetype, var);
var = fold_build2 (POINTER_PLUS_EXPR, utype, ubase, var);
}
else
{
var = fold_convert (utype, var);
var = fold_build2 (neg_p ? MINUS_EXPR : PLUS_EXPR, utype,
ubase, var);
}
return var;
}
/* Adjust the cost COST for being in loop setup rather than loop body.
If we're optimizing for space, the loop setup overhead is constant;
if we're optimizing for speed, amortize it over the per-iteration cost.
If ROUND_UP_P is true, the result is round up rather than to zero when
optimizing for speed. */
static int64_t
adjust_setup_cost (struct ivopts_data *data, int64_t cost,
bool round_up_p = false)
{
if (cost == INFTY)
return cost;
else if (optimize_loop_for_speed_p (data->current_loop))
{
int64_t niters = (int64_t) avg_loop_niter (data->current_loop);
return (cost + (round_up_p ? niters - 1 : 0)) / niters;
}
else
return cost;
}
/* Calculate the SPEED or size cost of shiftadd EXPR in MODE. MULT is the
EXPR operand holding the shift. COST0 and COST1 are the costs for
calculating the operands of EXPR. Returns true if successful, and returns
the cost in COST. */
static bool
get_shiftadd_cost (tree expr, scalar_int_mode mode, comp_cost cost0,
comp_cost cost1, tree mult, bool speed, comp_cost *cost)
{
comp_cost res;
tree op1 = TREE_OPERAND (expr, 1);
tree cst = TREE_OPERAND (mult, 1);
tree multop = TREE_OPERAND (mult, 0);
int m = exact_log2 (int_cst_value (cst));
int maxm = MIN (BITS_PER_WORD, GET_MODE_BITSIZE (mode));
int as_cost, sa_cost;
bool mult_in_op1;
if (!(m >= 0 && m < maxm))
return false;
STRIP_NOPS (op1);
mult_in_op1 = operand_equal_p (op1, mult, 0);
as_cost = add_cost (speed, mode) + shift_cost (speed, mode, m);
/* If the target has a cheap shift-and-add or shift-and-sub instruction,
use that in preference to a shift insn followed by an add insn. */
sa_cost = (TREE_CODE (expr) != MINUS_EXPR
? shiftadd_cost (speed, mode, m)
: (mult_in_op1
? shiftsub1_cost (speed, mode, m)
: shiftsub0_cost (speed, mode, m)));
res = comp_cost (MIN (as_cost, sa_cost), 0);
res += (mult_in_op1 ? cost0 : cost1);
STRIP_NOPS (multop);
if (!is_gimple_val (multop))
res += force_expr_to_var_cost (multop, speed);
*cost = res;
return true;
}
/* Estimates cost of forcing expression EXPR into a variable. */
static comp_cost
force_expr_to_var_cost (tree expr, bool speed)
{
static bool costs_initialized = false;
static unsigned integer_cost [2];
static unsigned symbol_cost [2];
static unsigned address_cost [2];
tree op0, op1;
comp_cost cost0, cost1, cost;
machine_mode mode;
scalar_int_mode int_mode;
if (!costs_initialized)
{
tree type = build_pointer_type (integer_type_node);
tree var, addr;
rtx x;
int i;
var = create_tmp_var_raw (integer_type_node, "test_var");
TREE_STATIC (var) = 1;
x = produce_memory_decl_rtl (var, NULL);
SET_DECL_RTL (var, x);
addr = build1 (ADDR_EXPR, type, var);
for (i = 0; i < 2; i++)
{
integer_cost[i] = computation_cost (build_int_cst (integer_type_node,
2000), i);
symbol_cost[i] = computation_cost (addr, i) + 1;
address_cost[i]
= computation_cost (fold_build_pointer_plus_hwi (addr, 2000), i) + 1;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "force_expr_to_var_cost %s costs:\n", i ? "speed" : "size");
fprintf (dump_file, " integer %d\n", (int) integer_cost[i]);
fprintf (dump_file, " symbol %d\n", (int) symbol_cost[i]);
fprintf (dump_file, " address %d\n", (int) address_cost[i]);
fprintf (dump_file, " other %d\n", (int) target_spill_cost[i]);
fprintf (dump_file, "\n");
}
}
costs_initialized = true;
}
STRIP_NOPS (expr);
if (SSA_VAR_P (expr))
return no_cost;
if (is_gimple_min_invariant (expr))
{
if (poly_int_tree_p (expr))
return comp_cost (integer_cost [speed], 0);
if (TREE_CODE (expr) == ADDR_EXPR)
{
tree obj = TREE_OPERAND (expr, 0);
if (VAR_P (obj)
|| TREE_CODE (obj) == PARM_DECL
|| TREE_CODE (obj) == RESULT_DECL)
return comp_cost (symbol_cost [speed], 0);
}
return comp_cost (address_cost [speed], 0);
}
switch (TREE_CODE (expr))
{
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
case MULT_EXPR:
case TRUNC_DIV_EXPR:
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
case LSHIFT_EXPR:
case RSHIFT_EXPR:
op0 = TREE_OPERAND (expr, 0);
op1 = TREE_OPERAND (expr, 1);
STRIP_NOPS (op0);
STRIP_NOPS (op1);
break;
CASE_CONVERT:
case NEGATE_EXPR:
case BIT_NOT_EXPR:
op0 = TREE_OPERAND (expr, 0);
STRIP_NOPS (op0);
op1 = NULL_TREE;
break;
/* See add_iv_candidate_for_doloop, for doloop may_be_zero case, we
introduce COND_EXPR for IV base, need to support better cost estimation
for this COND_EXPR and tcc_comparison. */
case COND_EXPR:
op0 = TREE_OPERAND (expr, 1);
STRIP_NOPS (op0);
op1 = TREE_OPERAND (expr, 2);
STRIP_NOPS (op1);
break;
case LT_EXPR:
case LE_EXPR:
case GT_EXPR:
case GE_EXPR:
case EQ_EXPR:
case NE_EXPR:
case UNORDERED_EXPR:
case ORDERED_EXPR:
case UNLT_EXPR:
case UNLE_EXPR:
case UNGT_EXPR:
case UNGE_EXPR:
case UNEQ_EXPR:
case LTGT_EXPR:
case MAX_EXPR:
case MIN_EXPR:
op0 = TREE_OPERAND (expr, 0);
STRIP_NOPS (op0);
op1 = TREE_OPERAND (expr, 1);
STRIP_NOPS (op1);
break;
default:
/* Just an arbitrary value, FIXME. */
return comp_cost (target_spill_cost[speed], 0);
}
if (op0 == NULL_TREE
|| TREE_CODE (op0) == SSA_NAME || CONSTANT_CLASS_P (op0))
cost0 = no_cost;
else
cost0 = force_expr_to_var_cost (op0, speed);
if (op1 == NULL_TREE
|| TREE_CODE (op1) == SSA_NAME || CONSTANT_CLASS_P (op1))
cost1 = no_cost;
else
cost1 = force_expr_to_var_cost (op1, speed);
mode = TYPE_MODE (TREE_TYPE (expr));
switch (TREE_CODE (expr))
{
case POINTER_PLUS_EXPR:
case PLUS_EXPR:
case MINUS_EXPR:
case NEGATE_EXPR:
cost = comp_cost (add_cost (speed, mode), 0);
if (TREE_CODE (expr) != NEGATE_EXPR)
{
tree mult = NULL_TREE;
comp_cost sa_cost;
if (TREE_CODE (op1) == MULT_EXPR)
mult = op1;
else if (TREE_CODE (op0) == MULT_EXPR)
mult = op0;
if (mult != NULL_TREE
&& is_a <scalar_int_mode> (mode, &int_mode)
&& cst_and_fits_in_hwi (TREE_OPERAND (mult, 1))
&& get_shiftadd_cost (expr, int_mode, cost0, cost1, mult,
speed, &sa_cost))
return sa_cost;
}
break;
CASE_CONVERT:
{
tree inner_mode, outer_mode;
outer_mode = TREE_TYPE (expr);
inner_mode = TREE_TYPE (op0);
cost = comp_cost (convert_cost (TYPE_MODE (outer_mode),
TYPE_MODE (inner_mode), speed), 0);
}
break;
case MULT_EXPR:
if (cst_and_fits_in_hwi (op0))
cost = comp_cost (mult_by_coeff_cost (int_cst_value (op0),
mode, speed), 0);
else if (cst_and_fits_in_hwi (op1))
cost = comp_cost (mult_by_coeff_cost (int_cst_value (op1),
mode, speed), 0);
else
return comp_cost (target_spill_cost [speed], 0);
break;
case TRUNC_DIV_EXPR:
/* Division by power of two is usually cheap, so we allow it. Forbid
anything else. */
if (integer_pow2p (TREE_OPERAND (expr, 1)))
cost = comp_cost (add_cost (speed, mode), 0);
else
cost = comp_cost (target_spill_cost[speed], 0);
break;
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
case BIT_NOT_EXPR:
case LSHIFT_EXPR:
case RSHIFT_EXPR:
cost = comp_cost (add_cost (speed, mode), 0);
break;
case COND_EXPR:
op0 = TREE_OPERAND (expr, 0);
STRIP_NOPS (op0);
if (op0 == NULL_TREE || TREE_CODE (op0) == SSA_NAME
|| CONSTANT_CLASS_P (op0))
cost = no_cost;
else
cost = force_expr_to_var_cost (op0, speed);
break;
case LT_EXPR:
case LE_EXPR:
case GT_EXPR:
case GE_EXPR:
case EQ_EXPR:
case NE_EXPR:
case UNORDERED_EXPR:
case ORDERED_EXPR:
case UNLT_EXPR:
case UNLE_EXPR:
case UNGT_EXPR:
case UNGE_EXPR:
case UNEQ_EXPR:
case LTGT_EXPR:
case MAX_EXPR:
case MIN_EXPR:
/* Simply use add cost for now, FIXME if there is some more accurate cost
evaluation way. */
cost = comp_cost (add_cost (speed, mode), 0);
break;
default:
gcc_unreachable ();
}
cost += cost0;
cost += cost1;
return cost;
}
/* Estimates cost of forcing EXPR into a variable. INV_VARS is a set of the
invariants the computation depends on. */
static comp_cost
force_var_cost (struct ivopts_data *data, tree expr, bitmap *inv_vars)
{
if (!expr)
return no_cost;
find_inv_vars (data, &expr, inv_vars);
return force_expr_to_var_cost (expr, data->speed);
}
/* Returns cost of auto-modifying address expression in shape base + offset.
AINC_STEP is step size of the address IV. AINC_OFFSET is offset of the
address expression. The address expression has ADDR_MODE in addr space
AS. The memory access has MEM_MODE. SPEED means we are optimizing for
speed or size. */
enum ainc_type
{
AINC_PRE_INC, /* Pre increment. */
AINC_PRE_DEC, /* Pre decrement. */
AINC_POST_INC, /* Post increment. */
AINC_POST_DEC, /* Post decrement. */
AINC_NONE /* Also the number of auto increment types. */
};
struct ainc_cost_data
{
int64_t costs[AINC_NONE];
};
static comp_cost
get_address_cost_ainc (poly_int64 ainc_step, poly_int64 ainc_offset,
machine_mode addr_mode, machine_mode mem_mode,
addr_space_t as, bool speed)
{
if (!USE_LOAD_PRE_DECREMENT (mem_mode)
&& !USE_STORE_PRE_DECREMENT (mem_mode)
&& !USE_LOAD_POST_DECREMENT (mem_mode)
&& !USE_STORE_POST_DECREMENT (mem_mode)
&& !USE_LOAD_PRE_INCREMENT (mem_mode)
&& !USE_STORE_PRE_INCREMENT (mem_mode)
&& !USE_LOAD_POST_INCREMENT (mem_mode)
&& !USE_STORE_POST_INCREMENT (mem_mode))
return infinite_cost;
static vec<ainc_cost_data *> ainc_cost_data_list;
unsigned idx = (unsigned) as * MAX_MACHINE_MODE + (unsigned) mem_mode;
if (idx >= ainc_cost_data_list.length ())
{
unsigned nsize = ((unsigned) as + 1) *MAX_MACHINE_MODE;
gcc_assert (nsize > idx);
ainc_cost_data_list.safe_grow_cleared (nsize, true);
}
ainc_cost_data *data = ainc_cost_data_list[idx];
if (data == NULL)
{
rtx reg = gen_raw_REG (addr_mode, LAST_VIRTUAL_REGISTER + 1);
data = (ainc_cost_data *) xcalloc (1, sizeof (*data));
data->costs[AINC_PRE_DEC] = INFTY;
data->costs[AINC_POST_DEC] = INFTY;
data->costs[AINC_PRE_INC] = INFTY;
data->costs[AINC_POST_INC] = INFTY;
if (USE_LOAD_PRE_DECREMENT (mem_mode)
|| USE_STORE_PRE_DECREMENT (mem_mode))
{
rtx addr = gen_rtx_PRE_DEC (addr_mode, reg);
if (memory_address_addr_space_p (mem_mode, addr, as))
data->costs[AINC_PRE_DEC]
= address_cost (addr, mem_mode, as, speed);
}
if (USE_LOAD_POST_DECREMENT (mem_mode)
|| USE_STORE_POST_DECREMENT (mem_mode))
{
rtx addr = gen_rtx_POST_DEC (addr_mode, reg);
if (memory_address_addr_space_p (mem_mode, addr, as))
data->costs[AINC_POST_DEC]
= address_cost (addr, mem_mode, as, speed);
}
if (USE_LOAD_PRE_INCREMENT (mem_mode)
|| USE_STORE_PRE_INCREMENT (mem_mode))
{
rtx addr = gen_rtx_PRE_INC (addr_mode, reg);
if (memory_address_addr_space_p (mem_mode, addr, as))
data->costs[AINC_PRE_INC]
= address_cost (addr, mem_mode, as, speed);
}
if (USE_LOAD_POST_INCREMENT (mem_mode)
|| USE_STORE_POST_INCREMENT (mem_mode))
{
rtx addr = gen_rtx_POST_INC (addr_mode, reg);
if (memory_address_addr_space_p (mem_mode, addr, as))
data->costs[AINC_POST_INC]
= address_cost (addr, mem_mode, as, speed);
}
ainc_cost_data_list[idx] = data;
}
poly_int64 msize = GET_MODE_SIZE (mem_mode);
if (known_eq (ainc_offset, 0) && known_eq (msize, ainc_step))
return comp_cost (data->costs[AINC_POST_INC], 0);
if (known_eq (ainc_offset, 0) && known_eq (msize, -ainc_step))
return comp_cost (data->costs[AINC_POST_DEC], 0);
if (known_eq (ainc_offset, msize) && known_eq (msize, ainc_step))
return comp_cost (data->costs[AINC_PRE_INC], 0);
if (known_eq (ainc_offset, -msize) && known_eq (msize, -ainc_step))
return comp_cost (data->costs[AINC_PRE_DEC], 0);
return infinite_cost;
}
/* Return cost of computing USE's address expression by using CAND.
AFF_INV and AFF_VAR represent invariant and variant parts of the
address expression, respectively. If AFF_INV is simple, store
the loop invariant variables which are depended by it in INV_VARS;
if AFF_INV is complicated, handle it as a new invariant expression
and record it in INV_EXPR. RATIO indicates multiple times between
steps of USE and CAND. If CAN_AUTOINC is nonNULL, store boolean
value to it indicating if this is an auto-increment address. */
static comp_cost
get_address_cost (struct ivopts_data *data, struct iv_use *use,
struct iv_cand *cand, aff_tree *aff_inv,
aff_tree *aff_var, HOST_WIDE_INT ratio,
bitmap *inv_vars, iv_inv_expr_ent **inv_expr,
bool *can_autoinc, bool speed)
{
rtx addr;
bool simple_inv = true;
tree comp_inv = NULL_TREE, type = aff_var->type;
comp_cost var_cost = no_cost, cost = no_cost;
struct mem_address parts = {NULL_TREE, integer_one_node,
NULL_TREE, NULL_TREE, NULL_TREE};
machine_mode addr_mode = TYPE_MODE (type);
machine_mode mem_mode = TYPE_MODE (use->mem_type);
addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (use->iv->base));
/* Only true if ratio != 1. */
bool ok_with_ratio_p = false;
bool ok_without_ratio_p = false;
if (!aff_combination_const_p (aff_inv))
{
parts.index = integer_one_node;
/* Addressing mode "base + index". */
ok_without_ratio_p = valid_mem_ref_p (mem_mode, as, &parts);
if (ratio != 1)
{
parts.step = wide_int_to_tree (type, ratio);
/* Addressing mode "base + index << scale". */
ok_with_ratio_p = valid_mem_ref_p (mem_mode, as, &parts);
if (!ok_with_ratio_p)
parts.step = NULL_TREE;
}
if (ok_with_ratio_p || ok_without_ratio_p)
{
if (maybe_ne (aff_inv->offset, 0))
{
parts.offset = wide_int_to_tree (sizetype, aff_inv->offset);
/* Addressing mode "base + index [<< scale] + offset". */
if (!valid_mem_ref_p (mem_mode, as, &parts))
parts.offset = NULL_TREE;
else
aff_inv->offset = 0;
}
move_fixed_address_to_symbol (&parts, aff_inv);
/* Base is fixed address and is moved to symbol part. */
if (parts.symbol != NULL_TREE && aff_combination_zero_p (aff_inv))
parts.base = NULL_TREE;
/* Addressing mode "symbol + base + index [<< scale] [+ offset]". */
if (parts.symbol != NULL_TREE
&& !valid_mem_ref_p (mem_mode, as, &parts))
{
aff_combination_add_elt (aff_inv, parts.symbol, 1);
parts.symbol = NULL_TREE;
/* Reset SIMPLE_INV since symbol address needs to be computed
outside of address expression in this case. */
simple_inv = false;
/* Symbol part is moved back to base part, it can't be NULL. */
parts.base = integer_one_node;
}
}
else
parts.index = NULL_TREE;
}
else
{
poly_int64 ainc_step;
if (can_autoinc
&& ratio == 1
&& ptrdiff_tree_p (cand->iv->step, &ainc_step))
{
poly_int64 ainc_offset = (aff_inv->offset).force_shwi ();
if (stmt_after_increment (data->current_loop, cand, use->stmt))
ainc_offset += ainc_step;
cost = get_address_cost_ainc (ainc_step, ainc_offset,
addr_mode, mem_mode, as, speed);
if (!cost.infinite_cost_p ())
{
*can_autoinc = true;
return cost;
}
cost = no_cost;
}
if (!aff_combination_zero_p (aff_inv))
{
parts.offset = wide_int_to_tree (sizetype, aff_inv->offset);
/* Addressing mode "base + offset". */
if (!valid_mem_ref_p (mem_mode, as, &parts))
parts.offset = NULL_TREE;
else
aff_inv->offset = 0;
}
}
if (simple_inv)
simple_inv = (aff_inv == NULL
|| aff_combination_const_p (aff_inv)
|| aff_combination_singleton_var_p (aff_inv));
if (!aff_combination_zero_p (aff_inv))
comp_inv = aff_combination_to_tree (aff_inv);
if (comp_inv != NULL_TREE)
cost = force_var_cost (data, comp_inv, inv_vars);
if (ratio != 1 && parts.step == NULL_TREE)
var_cost += mult_by_coeff_cost (ratio, addr_mode, speed);
if (comp_inv != NULL_TREE && parts.index == NULL_TREE)
var_cost += add_cost (speed, addr_mode);
if (comp_inv && inv_expr && !simple_inv)
{
*inv_expr = get_loop_invariant_expr (data, comp_inv);
/* Clear depends on. */
if (*inv_expr != NULL && inv_vars && *inv_vars)
bitmap_clear (*inv_vars);
/* Cost of small invariant expression adjusted against loop niters
is usually zero, which makes it difficult to be differentiated
from candidate based on loop invariant variables. Secondly, the
generated invariant expression may not be hoisted out of loop by
following pass. We penalize the cost by rounding up in order to
neutralize such effects. */
cost.cost = adjust_setup_cost (data, cost.cost, true);
cost.scratch = cost.cost;
}
cost += var_cost;
addr = addr_for_mem_ref (&parts, as, false);
gcc_assert (memory_address_addr_space_p (mem_mode, addr, as));
cost += address_cost (addr, mem_mode, as, speed);
if (parts.symbol != NULL_TREE)
cost.complexity += 1;
/* Don't increase the complexity of adding a scaled index if it's
the only kind of index that the target allows. */
if (parts.step != NULL_TREE && ok_without_ratio_p)
cost.complexity += 1;
if (parts.base != NULL_TREE && parts.index != NULL_TREE)
cost.complexity += 1;
if (parts.offset != NULL_TREE && !integer_zerop (parts.offset))
cost.complexity += 1;
return cost;
}
/* Scale (multiply) the computed COST (except scratch part that should be
hoisted out a loop) by header->frequency / AT->frequency, which makes
expected cost more accurate. */
static comp_cost
get_scaled_computation_cost_at (ivopts_data *data, gimple *at, comp_cost cost)
{
if (data->speed
&& data->current_loop->header->count.to_frequency (cfun) > 0)
{
basic_block bb = gimple_bb (at);
gcc_assert (cost.scratch <= cost.cost);
int scale_factor = (int)(intptr_t) bb->aux;
if (scale_factor == 1)
return cost;
int64_t scaled_cost
= cost.scratch + (cost.cost - cost.scratch) * scale_factor;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Scaling cost based on bb prob by %2.2f: "
"%" PRId64 " (scratch: %" PRId64 ") -> %" PRId64 "\n",
1.0f * scale_factor, cost.cost, cost.scratch, scaled_cost);
cost.cost = scaled_cost;
}
return cost;
}
/* Determines the cost of the computation by that USE is expressed
from induction variable CAND. If ADDRESS_P is true, we just need
to create an address from it, otherwise we want to get it into
register. A set of invariants we depend on is stored in INV_VARS.
If CAN_AUTOINC is nonnull, use it to record whether autoinc
addressing is likely. If INV_EXPR is nonnull, record invariant
expr entry in it. */
static comp_cost
get_computation_cost (struct ivopts_data *data, struct iv_use *use,
struct iv_cand *cand, bool address_p, bitmap *inv_vars,
bool *can_autoinc, iv_inv_expr_ent **inv_expr)
{
gimple *at = use->stmt;
tree ubase = use->iv->base, cbase = cand->iv->base;
tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase);
tree comp_inv = NULL_TREE;
HOST_WIDE_INT ratio, aratio;
comp_cost cost;
widest_int rat;
aff_tree aff_inv, aff_var;
bool speed = optimize_bb_for_speed_p (gimple_bb (at));
if (inv_vars)
*inv_vars = NULL;
if (can_autoinc)
*can_autoinc = false;
if (inv_expr)
*inv_expr = NULL;
/* Check if we have enough precision to express the values of use. */
if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype))
return infinite_cost;
if (address_p
|| (use->iv->base_object
&& cand->iv->base_object
&& POINTER_TYPE_P (TREE_TYPE (use->iv->base_object))
&& POINTER_TYPE_P (TREE_TYPE (cand->iv->base_object))))
{
/* Do not try to express address of an object with computation based
on address of a different object. This may cause problems in rtl
level alias analysis (that does not expect this to be happening,
as this is illegal in C), and would be unlikely to be useful
anyway. */
if (use->iv->base_object
&& cand->iv->base_object
&& !operand_equal_p (use->iv->base_object, cand->iv->base_object, 0))
return infinite_cost;
}
if (!get_computation_aff_1 (data->current_loop, at, use,
cand, &aff_inv, &aff_var, &rat)
|| !wi::fits_shwi_p (rat))
return infinite_cost;
ratio = rat.to_shwi ();
if (address_p)
{
cost = get_address_cost (data, use, cand, &aff_inv, &aff_var, ratio,
inv_vars, inv_expr, can_autoinc, speed);
cost = get_scaled_computation_cost_at (data, at, cost);
/* For doloop IV cand, add on the extra cost. */
cost += cand->doloop_p ? targetm.doloop_cost_for_address : 0;
return cost;
}
bool simple_inv = (aff_combination_const_p (&aff_inv)
|| aff_combination_singleton_var_p (&aff_inv));
tree signed_type = signed_type_for (aff_combination_type (&aff_inv));
aff_combination_convert (&aff_inv, signed_type);
if (!aff_combination_zero_p (&aff_inv))
comp_inv = aff_combination_to_tree (&aff_inv);
cost = force_var_cost (data, comp_inv, inv_vars);
if (comp_inv && inv_expr && !simple_inv)
{
*inv_expr = get_loop_invariant_expr (data, comp_inv);
/* Clear depends on. */
if (*inv_expr != NULL && inv_vars && *inv_vars)
bitmap_clear (*inv_vars);
cost.cost = adjust_setup_cost (data, cost.cost);
/* Record setup cost in scratch field. */
cost.scratch = cost.cost;
}
/* Cost of constant integer can be covered when adding invariant part to
variant part. */
else if (comp_inv && CONSTANT_CLASS_P (comp_inv))
cost = no_cost;
/* Need type narrowing to represent use with cand. */
if (TYPE_PRECISION (utype) < TYPE_PRECISION (ctype))
{
machine_mode outer_mode = TYPE_MODE (utype);
machine_mode inner_mode = TYPE_MODE (ctype);
cost += comp_cost (convert_cost (outer_mode, inner_mode, speed), 0);
}
/* Turn a + i * (-c) into a - i * c. */
if (ratio < 0 && comp_inv && !integer_zerop (comp_inv))
aratio = -ratio;
else
aratio = ratio;
if (ratio != 1)
cost += mult_by_coeff_cost (aratio, TYPE_MODE (utype), speed);
/* TODO: We may also need to check if we can compute a + i * 4 in one
instruction. */
/* Need to add up the invariant and variant parts. */
if (comp_inv && !integer_zerop (comp_inv))
cost += add_cost (speed, TYPE_MODE (utype));
cost = get_scaled_computation_cost_at (data, at, cost);
/* For doloop IV cand, add on the extra cost. */
if (cand->doloop_p && use->type == USE_NONLINEAR_EXPR)
cost += targetm.doloop_cost_for_generic;
return cost;
}
/* Determines cost of computing the use in GROUP with CAND in a generic
expression. */
static bool
determine_group_iv_cost_generic (struct ivopts_data *data,
struct iv_group *group, struct iv_cand *cand)
{
comp_cost cost;
iv_inv_expr_ent *inv_expr = NULL;
bitmap inv_vars = NULL, inv_exprs = NULL;
struct iv_use *use = group->vuses[0];
/* The simple case first -- if we need to express value of the preserved
original biv, the cost is 0. This also prevents us from counting the
cost of increment twice -- once at this use and once in the cost of
the candidate. */
if (cand->pos == IP_ORIGINAL && cand->incremented_at == use->stmt)
cost = no_cost;
/* If the IV candidate involves undefined SSA values and is not the
same IV as on the USE avoid using that candidate here. */
else if (cand->involves_undefs
&& (!use->iv || !operand_equal_p (cand->iv->base, use->iv->base, 0)))
return false;
else
cost = get_computation_cost (data, use, cand, false,
&inv_vars, NULL, &inv_expr);
if (inv_expr)
{
inv_exprs = BITMAP_ALLOC (NULL);
bitmap_set_bit (inv_exprs, inv_expr->id);
}
set_group_iv_cost (data, group, cand, cost, inv_vars,
NULL_TREE, ERROR_MARK, inv_exprs);
return !cost.infinite_cost_p ();
}
/* Determines cost of computing uses in GROUP with CAND in addresses. */
static bool
determine_group_iv_cost_address (struct ivopts_data *data,
struct iv_group *group, struct iv_cand *cand)
{
unsigned i;
bitmap inv_vars = NULL, inv_exprs = NULL;
bool can_autoinc;
iv_inv_expr_ent *inv_expr = NULL;
struct iv_use *use = group->vuses[0];
comp_cost sum_cost = no_cost, cost;
cost = get_computation_cost (data, use, cand, true,
&inv_vars, &can_autoinc, &inv_expr);
if (inv_expr)
{
inv_exprs = BITMAP_ALLOC (NULL);
bitmap_set_bit (inv_exprs, inv_expr->id);
}
sum_cost = cost;
if (!sum_cost.infinite_cost_p () && cand->ainc_use == use)
{
if (can_autoinc)
sum_cost -= cand->cost_step;
/* If we generated the candidate solely for exploiting autoincrement
opportunities, and it turns out it can't be used, set the cost to
infinity to make sure we ignore it. */
else if (cand->pos == IP_AFTER_USE || cand->pos == IP_BEFORE_USE)
sum_cost = infinite_cost;
}
/* Uses in a group can share setup code, so only add setup cost once. */
cost -= cost.scratch;
/* Compute and add costs for rest uses of this group. */
for (i = 1; i < group->vuses.length () && !sum_cost.infinite_cost_p (); i++)
{
struct iv_use *next = group->vuses[i];
/* TODO: We could skip computing cost for sub iv_use when it has the
same cost as the first iv_use, but the cost really depends on the
offset and where the iv_use is. */
cost = get_computation_cost (data, next, cand, true,
NULL, &can_autoinc, &inv_expr);
if (inv_expr)
{
if (!inv_exprs)
inv_exprs = BITMAP_ALLOC (NULL);
bitmap_set_bit (inv_exprs, inv_expr->id);
}
sum_cost += cost;
}
set_group_iv_cost (data, group, cand, sum_cost, inv_vars,
NULL_TREE, ERROR_MARK, inv_exprs);
return !sum_cost.infinite_cost_p ();
}
/* Computes value of candidate CAND at position AT in iteration DESC->NITER,
and stores it to VAL. */
static void
cand_value_at (class loop *loop, struct iv_cand *cand, gimple *at,
class tree_niter_desc *desc, aff_tree *val)
{
aff_tree step, delta, nit;
struct iv *iv = cand->iv;
tree type = TREE_TYPE (iv->base);
tree niter = desc->niter;
bool after_adjust = stmt_after_increment (loop, cand, at);
tree steptype;
if (POINTER_TYPE_P (type))
steptype = sizetype;
else
steptype = unsigned_type_for (type);
/* If AFTER_ADJUST is required, the code below generates the equivalent
of BASE + NITER * STEP + STEP, when ideally we'd prefer the expression
BASE + (NITER + 1) * STEP, especially when NITER is often of the form
SSA_NAME - 1. Unfortunately, guaranteeing that adding 1 to NITER
doesn't overflow is tricky, so we peek inside the TREE_NITER_DESC
class for common idioms that we know are safe. */
if (after_adjust
&& desc->control.no_overflow
&& integer_onep (desc->control.step)
&& (desc->cmp == LT_EXPR
|| desc->cmp == NE_EXPR)
&& TREE_CODE (desc->bound) == SSA_NAME)
{
if (integer_onep (desc->control.base))
{
niter = desc->bound;
after_adjust = false;
}
else if (TREE_CODE (niter) == MINUS_EXPR
&& integer_onep (TREE_OPERAND (niter, 1)))
{
niter = TREE_OPERAND (niter, 0);
after_adjust = false;
}
}
tree_to_aff_combination (iv->step, TREE_TYPE (iv->step), &step);
aff_combination_convert (&step, steptype);
tree_to_aff_combination (niter, TREE_TYPE (niter), &nit);
aff_combination_convert (&nit, steptype);
aff_combination_mult (&nit, &step, &delta);
if (after_adjust)
aff_combination_add (&delta, &step);
tree_to_aff_combination (iv->base, type, val);
if (!POINTER_TYPE_P (type))
aff_combination_convert (val, steptype);
aff_combination_add (val, &delta);
}
/* Returns period of induction variable iv. */
static tree
iv_period (struct iv *iv)
{
tree step = iv->step, period, type;
tree pow2div;
gcc_assert (step && TREE_CODE (step) == INTEGER_CST);
type = unsigned_type_for (TREE_TYPE (step));
/* Period of the iv is lcm (step, type_range)/step -1,
i.e., N*type_range/step - 1. Since type range is power
of two, N == (step >> num_of_ending_zeros_binary (step),
so the final result is
(type_range >> num_of_ending_zeros_binary (step)) - 1
*/
pow2div = num_ending_zeros (step);
period = build_low_bits_mask (type,
(TYPE_PRECISION (type)
- tree_to_uhwi (pow2div)));
return period;
}
/* Returns the comparison operator used when eliminating the iv USE. */
static enum tree_code
iv_elimination_compare (struct ivopts_data *data, struct iv_use *use)
{
class loop *loop = data->current_loop;
basic_block ex_bb;
edge exit;
ex_bb = gimple_bb (use->stmt);
exit = EDGE_SUCC (ex_bb, 0);
if (flow_bb_inside_loop_p (loop, exit->dest))
exit = EDGE_SUCC (ex_bb, 1);
return (exit->flags & EDGE_TRUE_VALUE ? EQ_EXPR : NE_EXPR);
}
/* Returns true if we can prove that BASE - OFFSET does not overflow. For now,
we only detect the situation that BASE = SOMETHING + OFFSET, where the
calculation is performed in non-wrapping type.
TODO: More generally, we could test for the situation that
BASE = SOMETHING + OFFSET' and OFFSET is between OFFSET' and zero.
This would require knowing the sign of OFFSET. */
static bool
difference_cannot_overflow_p (struct ivopts_data *data, tree base, tree offset)
{
enum tree_code code;
tree e1, e2;
aff_tree aff_e1, aff_e2, aff_offset;
if (!nowrap_type_p (TREE_TYPE (base)))
return false;
base = expand_simple_operations (base);
if (TREE_CODE (base) == SSA_NAME)
{
gimple *stmt = SSA_NAME_DEF_STMT (base);
if (gimple_code (stmt) != GIMPLE_ASSIGN)
return false;
code = gimple_assign_rhs_code (stmt);
if (get_gimple_rhs_class (code) != GIMPLE_BINARY_RHS)
return false;
e1 = gimple_assign_rhs1 (stmt);
e2 = gimple_assign_rhs2 (stmt);
}
else
{
code = TREE_CODE (base);
if (get_gimple_rhs_class (code) != GIMPLE_BINARY_RHS)
return false;
e1 = TREE_OPERAND (base, 0);
e2 = TREE_OPERAND (base, 1);
}
/* Use affine expansion as deeper inspection to prove the equality. */
tree_to_aff_combination_expand (e2, TREE_TYPE (e2),
&aff_e2, &data->name_expansion_cache);
tree_to_aff_combination_expand (offset, TREE_TYPE (offset),
&aff_offset, &data->name_expansion_cache);
aff_combination_scale (&aff_offset, -1);
switch (code)
{
case PLUS_EXPR:
aff_combination_add (&aff_e2, &aff_offset);
if (aff_combination_zero_p (&aff_e2))
return true;
tree_to_aff_combination_expand (e1, TREE_TYPE (e1),
&aff_e1, &data->name_expansion_cache);
aff_combination_add (&aff_e1, &aff_offset);
return aff_combination_zero_p (&aff_e1);
case POINTER_PLUS_EXPR:
aff_combination_add (&aff_e2, &aff_offset);
return aff_combination_zero_p (&aff_e2);
default:
return false;
}
}
/* Tries to replace loop exit by one formulated in terms of a LT_EXPR
comparison with CAND. NITER describes the number of iterations of
the loops. If successful, the comparison in COMP_P is altered accordingly.
We aim to handle the following situation:
sometype *base, *p;
int a, b, i;
i = a;
p = p_0 = base + a;
do
{
bla (*p);
p++;
i++;
}
while (i < b);
Here, the number of iterations of the loop is (a + 1 > b) ? 0 : b - a - 1.
We aim to optimize this to
p = p_0 = base + a;
do
{
bla (*p);
p++;
}
while (p < p_0 - a + b);
This preserves the correctness, since the pointer arithmetics does not
overflow. More precisely:
1) if a + 1 <= b, then p_0 - a + b is the final value of p, hence there is no
overflow in computing it or the values of p.
2) if a + 1 > b, then we need to verify that the expression p_0 - a does not
overflow. To prove this, we use the fact that p_0 = base + a. */
static bool
iv_elimination_compare_lt (struct ivopts_data *data,
struct iv_cand *cand, enum tree_code *comp_p,
class tree_niter_desc *niter)
{
tree cand_type, a, b, mbz, nit_type = TREE_TYPE (niter->niter), offset;
class aff_tree nit, tmpa, tmpb;
enum tree_code comp;
HOST_WIDE_INT step;
/* We need to know that the candidate induction variable does not overflow.
While more complex analysis may be used to prove this, for now just
check that the variable appears in the original program and that it
is computed in a type that guarantees no overflows. */
cand_type = TREE_TYPE (cand->iv->base);
if (cand->pos != IP_ORIGINAL || !nowrap_type_p (cand_type))
return false;
/* Make sure that the loop iterates till the loop bound is hit, as otherwise
the calculation of the BOUND could overflow, making the comparison
invalid. */
if (!data->loop_single_exit_p)
return false;
/* We need to be able to decide whether candidate is increasing or decreasing
in order to choose the right comparison operator. */
if (!cst_and_fits_in_hwi (cand->iv->step))
return false;
step = int_cst_value (cand->iv->step);
/* Check that the number of iterations matches the expected pattern:
a + 1 > b ? 0 : b - a - 1. */
mbz = niter->may_be_zero;
if (TREE_CODE (mbz) == GT_EXPR)
{
/* Handle a + 1 > b. */
tree op0 = TREE_OPERAND (mbz, 0);
if (TREE_CODE (op0) == PLUS_EXPR && integer_onep (TREE_OPERAND (op0, 1)))
{
a = TREE_OPERAND (op0, 0);
b = TREE_OPERAND (mbz, 1);
}
else
return false;
}
else if (TREE_CODE (mbz) == LT_EXPR)
{
tree op1 = TREE_OPERAND (mbz, 1);
/* Handle b < a + 1. */
if (TREE_CODE (op1) == PLUS_EXPR && integer_onep (TREE_OPERAND (op1, 1)))
{
a = TREE_OPERAND (op1, 0);
b = TREE_OPERAND (mbz, 0);
}
else
return false;
}
else
return false;
/* Expected number of iterations is B - A - 1. Check that it matches
the actual number, i.e., that B - A - NITER = 1. */
tree_to_aff_combination (niter->niter, nit_type, &nit);
tree_to_aff_combination (fold_convert (nit_type, a), nit_type, &tmpa);
tree_to_aff_combination (fold_convert (nit_type, b), nit_type, &tmpb);
aff_combination_scale (&nit, -1);
aff_combination_scale (&tmpa, -1);
aff_combination_add (&tmpb, &tmpa);
aff_combination_add (&tmpb, &nit);
if (tmpb.n != 0 || maybe_ne (tmpb.offset, 1))
return false;
/* Finally, check that CAND->IV->BASE - CAND->IV->STEP * A does not
overflow. */
offset = fold_build2 (MULT_EXPR, TREE_TYPE (cand->iv->step),
cand->iv->step,
fold_convert (TREE_TYPE (cand->iv->step), a));
if (!difference_cannot_overflow_p (data, cand->iv->base, offset))
return false;
/* Determine the new comparison operator. */
comp = step < 0 ? GT_EXPR : LT_EXPR;
if (*comp_p == NE_EXPR)
*comp_p = comp;
else if (*comp_p == EQ_EXPR)
*comp_p = invert_tree_comparison (comp, false);
else
gcc_unreachable ();
return true;
}
/* Check whether it is possible to express the condition in USE by comparison
of candidate CAND. If so, store the value compared with to BOUND, and the
comparison operator to COMP. */
static bool
may_eliminate_iv (struct ivopts_data *data,
struct iv_use *use, struct iv_cand *cand, tree *bound,
enum tree_code *comp)
{
basic_block ex_bb;
edge exit;
tree period;
class loop *loop = data->current_loop;
aff_tree bnd;
class tree_niter_desc *desc = NULL;
if (TREE_CODE (cand->iv->step) != INTEGER_CST)
return false;
/* For now works only for exits that dominate the loop latch.
TODO: extend to other conditions inside loop body. */
ex_bb = gimple_bb (use->stmt);
if (use->stmt != last_stmt (ex_bb)
|| gimple_code (use->stmt) != GIMPLE_COND
|| !dominated_by_p (CDI_DOMINATORS, loop->latch, ex_bb))
return false;
exit = EDGE_SUCC (ex_bb, 0);
if (flow_bb_inside_loop_p (loop, exit->dest))
exit = EDGE_SUCC (ex_bb, 1);
if (flow_bb_inside_loop_p (loop, exit->dest))
return false;
desc = niter_for_exit (data, exit);
if (!desc)
return false;
/* Determine whether we can use the variable to test the exit condition.
This is the case iff the period of the induction variable is greater
than the number of iterations for which the exit condition is true. */
period = iv_period (cand->iv);
/* If the number of iterations is constant, compare against it directly. */
if (TREE_CODE (desc->niter) == INTEGER_CST)
{
/* See cand_value_at. */
if (stmt_after_increment (loop, cand, use->stmt))
{
if (!tree_int_cst_lt (desc->niter, period))
return false;
}
else
{
if (tree_int_cst_lt (period, desc->niter))
return false;
}
}
/* If not, and if this is the only possible exit of the loop, see whether
we can get a conservative estimate on the number of iterations of the
entire loop and compare against that instead. */
else
{
widest_int period_value, max_niter;
max_niter = desc->max;
if (stmt_after_increment (loop, cand, use->stmt))
max_niter += 1;
period_value = wi::to_widest (period);
if (wi::gtu_p (max_niter, period_value))
{
/* See if we can take advantage of inferred loop bound
information. */
if (data->loop_single_exit_p)
{
if (!max_loop_iterations (loop, &max_niter))
return false;
/* The loop bound is already adjusted by adding 1. */
if (wi::gtu_p (max_niter, period_value))
return false;
}
else
return false;
}
}
/* For doloop IV cand, the bound would be zero. It's safe whether
may_be_zero set or not. */
if (cand->doloop_p)
{
*bound = build_int_cst (TREE_TYPE (cand->iv->base), 0);
*comp = iv_elimination_compare (data, use);
return true;
}
cand_value_at (loop, cand, use->stmt, desc, &bnd);
*bound = fold_convert (TREE_TYPE (cand->iv->base),
aff_combination_to_tree (&bnd));
*comp = iv_elimination_compare (data, use);
/* It is unlikely that computing the number of iterations using division
would be more profitable than keeping the original induction variable. */
if (expression_expensive_p (*bound))
return false;
/* Sometimes, it is possible to handle the situation that the number of
iterations may be zero unless additional assumptions by using <
instead of != in the exit condition.
TODO: we could also calculate the value MAY_BE_ZERO ? 0 : NITER and
base the exit condition on it. However, that is often too
expensive. */
if (!integer_zerop (desc->may_be_zero))
return iv_elimination_compare_lt (data, cand, comp, desc);
return true;
}
/* Calculates the cost of BOUND, if it is a PARM_DECL. A PARM_DECL must
be copied, if it is used in the loop body and DATA->body_includes_call. */
static int
parm_decl_cost (struct ivopts_data *data, tree bound)
{
tree sbound = bound;
STRIP_NOPS (sbound);
if (TREE_CODE (sbound) == SSA_NAME
&& SSA_NAME_IS_DEFAULT_DEF (sbound)
&& TREE_CODE (SSA_NAME_VAR (sbound)) == PARM_DECL
&& data->body_includes_call)
return COSTS_N_INSNS (1);
return 0;
}
/* Determines cost of computing the use in GROUP with CAND in a condition. */
static bool
determine_group_iv_cost_cond (struct ivopts_data *data,
struct iv_group *group, struct iv_cand *cand)
{
tree bound = NULL_TREE;
struct iv *cmp_iv;
bitmap inv_exprs = NULL;
bitmap inv_vars_elim = NULL, inv_vars_express = NULL, inv_vars;
comp_cost elim_cost = infinite_cost, express_cost, cost, bound_cost;
enum comp_iv_rewrite rewrite_type;
iv_inv_expr_ent *inv_expr_elim = NULL, *inv_expr_express = NULL, *inv_expr;
tree *control_var, *bound_cst;
enum tree_code comp = ERROR_MARK;
struct iv_use *use = group->vuses[0];
/* Extract condition operands. */
rewrite_type = extract_cond_operands (data, use->stmt, &control_var,
&bound_cst, NULL, &cmp_iv);
gcc_assert (rewrite_type != COMP_IV_NA);
/* Try iv elimination. */
if (rewrite_type == COMP_IV_ELIM
&& may_eliminate_iv (data, use, cand, &bound, &comp))
{
elim_cost = force_var_cost (data, bound, &inv_vars_elim);
if (elim_cost.cost == 0)
elim_cost.cost = parm_decl_cost (data, bound);
else if (TREE_CODE (bound) == INTEGER_CST)
elim_cost.cost = 0;
/* If we replace a loop condition 'i < n' with 'p < base + n',
inv_vars_elim will have 'base' and 'n' set, which implies that both
'base' and 'n' will be live during the loop. More likely,
'base + n' will be loop invariant, resulting in only one live value
during the loop. So in that case we clear inv_vars_elim and set
inv_expr_elim instead. */
if (inv_vars_elim && bitmap_count_bits (inv_vars_elim) > 1)
{
inv_expr_elim = get_loop_invariant_expr (data, bound);
bitmap_clear (inv_vars_elim);
}
/* The bound is a loop invariant, so it will be only computed
once. */
elim_cost.cost = adjust_setup_cost (data, elim_cost.cost);
}
/* When the condition is a comparison of the candidate IV against
zero, prefer this IV.
TODO: The constant that we're subtracting from the cost should
be target-dependent. This information should be added to the
target costs for each backend. */
if (!elim_cost.infinite_cost_p () /* Do not try to decrease infinite! */
&& integer_zerop (*bound_cst)
&& (operand_equal_p (*control_var, cand->var_after, 0)
|| operand_equal_p (*control_var, cand->var_before, 0)))
elim_cost -= 1;
express_cost = get_computation_cost (data, use, cand, false,
&inv_vars_express, NULL,
&inv_expr_express);
if (cmp_iv != NULL)
find_inv_vars (data, &cmp_iv->base, &inv_vars_express);
/* Count the cost of the original bound as well. */
bound_cost = force_var_cost (data, *bound_cst, NULL);
if (bound_cost.cost == 0)
bound_cost.cost = parm_decl_cost (data, *bound_cst);
else if (TREE_CODE (*bound_cst) == INTEGER_CST)
bound_cost.cost = 0;
express_cost += bound_cost;
/* Choose the better approach, preferring the eliminated IV. */
if (elim_cost <= express_cost)
{
cost = elim_cost;
inv_vars = inv_vars_elim;
inv_vars_elim = NULL;
inv_expr = inv_expr_elim;
/* For doloop candidate/use pair, adjust to zero cost. */
if (group->doloop_p && cand->doloop_p && elim_cost.cost > no_cost.cost)
cost = no_cost;
}
else
{
cost = express_cost;
inv_vars = inv_vars_express;
inv_vars_express = NULL;
bound = NULL_TREE;
comp = ERROR_MARK;
inv_expr = inv_expr_express;
}
if (inv_expr)
{
inv_exprs = BITMAP_ALLOC (NULL);
bitmap_set_bit (inv_exprs, inv_expr->id);
}
set_group_iv_cost (data, group, cand, cost,
inv_vars, bound, comp, inv_exprs);
if (inv_vars_elim)
BITMAP_FREE (inv_vars_elim);
if (inv_vars_express)
BITMAP_FREE (inv_vars_express);
return !cost.infinite_cost_p ();
}
/* Determines cost of computing uses in GROUP with CAND. Returns false
if USE cannot be represented with CAND. */
static bool
determine_group_iv_cost (struct ivopts_data *data,
struct iv_group *group, struct iv_cand *cand)
{
switch (group->type)
{
case USE_NONLINEAR_EXPR:
return determine_group_iv_cost_generic (data, group, cand);
case USE_REF_ADDRESS:
case USE_PTR_ADDRESS:
return determine_group_iv_cost_address (data, group, cand);
case USE_COMPARE:
return determine_group_iv_cost_cond (data, group, cand);
default:
gcc_unreachable ();
}
}
/* Return true if get_computation_cost indicates that autoincrement is
a possibility for the pair of USE and CAND, false otherwise. */
static bool
autoinc_possible_for_pair (struct ivopts_data *data, struct iv_use *use,
struct iv_cand *cand)
{
if (!address_p (use->type))
return false;
bool can_autoinc = false;
get_computation_cost (data, use, cand, true, NULL, &can_autoinc, NULL);
return can_autoinc;
}
/* Examine IP_ORIGINAL candidates to see if they are incremented next to a
use that allows autoincrement, and set their AINC_USE if possible. */
static void
set_autoinc_for_original_candidates (struct ivopts_data *data)
{
unsigned i, j;
for (i = 0; i < data->vcands.length (); i++)
{
struct iv_cand *cand = data->vcands[i];
struct iv_use *closest_before = NULL;
struct iv_use *closest_after = NULL;
if (cand->pos != IP_ORIGINAL)
continue;
for (j = 0; j < data->vgroups.length (); j++)
{
struct iv_group *group = data->vgroups[j];
struct iv_use *use = group->vuses[0];
unsigned uid = gimple_uid (use->stmt);
if (gimple_bb (use->stmt) != gimple_bb (cand->incremented_at))
continue;
if (uid < gimple_uid (cand->incremented_at)
&& (closest_before == NULL
|| uid > gimple_uid (closest_before->stmt)))
closest_before = use;
if (uid > gimple_uid (cand->incremented_at)
&& (closest_after == NULL
|| uid < gimple_uid (closest_after->stmt)))
closest_after = use;
}
if (closest_before != NULL
&& autoinc_possible_for_pair (data, closest_before, cand))
cand->ainc_use = closest_before;
else if (closest_after != NULL
&& autoinc_possible_for_pair (data, closest_after, cand))
cand->ainc_use = closest_after;
}
}
/* Relate compare use with all candidates. */
static void
relate_compare_use_with_all_cands (struct ivopts_data *data)
{
unsigned i, count = data->vcands.length ();
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
if (group->type == USE_COMPARE)
bitmap_set_range (group->related_cands, 0, count);
}
}
/* If PREFERRED_MODE is suitable and profitable, use the preferred
PREFERRED_MODE to compute doloop iv base from niter: base = niter + 1. */
static tree
compute_doloop_base_on_mode (machine_mode preferred_mode, tree niter,
const widest_int &iterations_max)
{
tree ntype = TREE_TYPE (niter);
tree pref_type = lang_hooks.types.type_for_mode (preferred_mode, 1);
if (!pref_type)
return fold_build2 (PLUS_EXPR, ntype, unshare_expr (niter),
build_int_cst (ntype, 1));
gcc_assert (TREE_CODE (pref_type) == INTEGER_TYPE);
int prec = TYPE_PRECISION (ntype);
int pref_prec = TYPE_PRECISION (pref_type);
tree base;
/* Check if the PREFERRED_MODED is able to present niter. */
if (pref_prec > prec
|| wi::ltu_p (iterations_max,
widest_int::from (wi::max_value (pref_prec, UNSIGNED),
UNSIGNED)))
{
/* No wrap, it is safe to use preferred type after niter + 1. */
if (wi::ltu_p (iterations_max,
widest_int::from (wi::max_value (prec, UNSIGNED),
UNSIGNED)))
{
/* This could help to optimize "-1 +1" pair when niter looks
like "n-1": n is in original mode. "base = (n - 1) + 1"
in PREFERRED_MODED: it could be base = (PREFERRED_TYPE)n. */
base = fold_build2 (PLUS_EXPR, ntype, unshare_expr (niter),
build_int_cst (ntype, 1));
base = fold_convert (pref_type, base);
}
/* To avoid wrap, convert niter to preferred type before plus 1. */
else
{
niter = fold_convert (pref_type, niter);
base = fold_build2 (PLUS_EXPR, pref_type, unshare_expr (niter),
build_int_cst (pref_type, 1));
}
}
else
base = fold_build2 (PLUS_EXPR, ntype, unshare_expr (niter),
build_int_cst (ntype, 1));
return base;
}
/* Add one doloop dedicated IV candidate:
- Base is (may_be_zero ? 1 : (niter + 1)).
- Step is -1. */
static void
add_iv_candidate_for_doloop (struct ivopts_data *data)
{
tree_niter_desc *niter_desc = niter_for_single_dom_exit (data);
gcc_assert (niter_desc && niter_desc->assumptions);
tree niter = niter_desc->niter;
tree ntype = TREE_TYPE (niter);
gcc_assert (TREE_CODE (ntype) == INTEGER_TYPE);
tree may_be_zero = niter_desc->may_be_zero;
if (may_be_zero && integer_zerop (may_be_zero))
may_be_zero = NULL_TREE;
if (may_be_zero)
{
if (COMPARISON_CLASS_P (may_be_zero))
{
niter = fold_build3 (COND_EXPR, ntype, may_be_zero,
build_int_cst (ntype, 0),
rewrite_to_non_trapping_overflow (niter));
}
/* Don't try to obtain the iteration count expression when may_be_zero is
integer_nonzerop (actually iteration count is one) or else. */
else
return;
}
machine_mode mode = TYPE_MODE (ntype);
machine_mode pref_mode = targetm.preferred_doloop_mode (mode);
tree base;
if (mode != pref_mode)
{
base = compute_doloop_base_on_mode (pref_mode, niter, niter_desc->max);
ntype = TREE_TYPE (base);
}
else
base = fold_build2 (PLUS_EXPR, ntype, unshare_expr (niter),
build_int_cst (ntype, 1));
add_candidate (data, base, build_int_cst (ntype, -1), true, NULL, NULL, true);
}
/* Finds the candidates for the induction variables. */
static void
find_iv_candidates (struct ivopts_data *data)
{
/* Add commonly used ivs. */
add_standard_iv_candidates (data);
/* Add doloop dedicated ivs. */
if (data->doloop_use_p)
add_iv_candidate_for_doloop (data);
/* Add old induction variables. */
add_iv_candidate_for_bivs (data);
/* Add induction variables derived from uses. */
add_iv_candidate_for_groups (data);
set_autoinc_for_original_candidates (data);
/* Record the important candidates. */
record_important_candidates (data);
/* Relate compare iv_use with all candidates. */
if (!data->consider_all_candidates)
relate_compare_use_with_all_cands (data);
if (dump_file && (dump_flags & TDF_DETAILS))
{
unsigned i;
fprintf (dump_file, "\n<Important Candidates>:\t");
for (i = 0; i < data->vcands.length (); i++)
if (data->vcands[i]->important)
fprintf (dump_file, " %d,", data->vcands[i]->id);
fprintf (dump_file, "\n");
fprintf (dump_file, "\n<Group, Cand> Related:\n");
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
if (group->related_cands)
{
fprintf (dump_file, " Group %d:\t", group->id);
dump_bitmap (dump_file, group->related_cands);
}
}
fprintf (dump_file, "\n");
}
}
/* Determines costs of computing use of iv with an iv candidate. */
static void
determine_group_iv_costs (struct ivopts_data *data)
{
unsigned i, j;
struct iv_cand *cand;
struct iv_group *group;
bitmap to_clear = BITMAP_ALLOC (NULL);
alloc_use_cost_map (data);
for (i = 0; i < data->vgroups.length (); i++)
{
group = data->vgroups[i];
if (data->consider_all_candidates)
{
for (j = 0; j < data->vcands.length (); j++)
{
cand = data->vcands[j];
determine_group_iv_cost (data, group, cand);
}
}
else
{
bitmap_iterator bi;
EXECUTE_IF_SET_IN_BITMAP (group->related_cands, 0, j, bi)
{
cand = data->vcands[j];
if (!determine_group_iv_cost (data, group, cand))
bitmap_set_bit (to_clear, j);
}
/* Remove the candidates for that the cost is infinite from
the list of related candidates. */
bitmap_and_compl_into (group->related_cands, to_clear);
bitmap_clear (to_clear);
}
}
BITMAP_FREE (to_clear);
if (dump_file && (dump_flags & TDF_DETAILS))
{
bitmap_iterator bi;
/* Dump invariant variables. */
fprintf (dump_file, "\n<Invariant Vars>:\n");
EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
{
struct version_info *info = ver_info (data, i);
if (info->inv_id)
{
fprintf (dump_file, "Inv %d:\t", info->inv_id);
print_generic_expr (dump_file, info->name, TDF_SLIM);
fprintf (dump_file, "%s\n",
info->has_nonlin_use ? "" : "\t(eliminable)");
}
}
/* Dump invariant expressions. */
fprintf (dump_file, "\n<Invariant Expressions>:\n");
auto_vec <iv_inv_expr_ent *> list (data->inv_expr_tab->elements ());
for (hash_table<iv_inv_expr_hasher>::iterator it
= data->inv_expr_tab->begin (); it != data->inv_expr_tab->end ();
++it)
list.safe_push (*it);
list.qsort (sort_iv_inv_expr_ent);
for (i = 0; i < list.length (); ++i)
{
fprintf (dump_file, "inv_expr %d: \t", list[i]->id);
print_generic_expr (dump_file, list[i]->expr, TDF_SLIM);
fprintf (dump_file, "\n");
}
fprintf (dump_file, "\n<Group-candidate Costs>:\n");
for (i = 0; i < data->vgroups.length (); i++)
{
group = data->vgroups[i];
fprintf (dump_file, "Group %d:\n", i);
fprintf (dump_file, " cand\tcost\tcompl.\tinv.expr.\tinv.vars\n");
for (j = 0; j < group->n_map_members; j++)
{
if (!group->cost_map[j].cand
|| group->cost_map[j].cost.infinite_cost_p ())
continue;
fprintf (dump_file, " %d\t%" PRId64 "\t%d\t",
group->cost_map[j].cand->id,
group->cost_map[j].cost.cost,
group->cost_map[j].cost.complexity);
if (!group->cost_map[j].inv_exprs
|| bitmap_empty_p (group->cost_map[j].inv_exprs))
fprintf (dump_file, "NIL;\t");
else
bitmap_print (dump_file,
group->cost_map[j].inv_exprs, "", ";\t");
if (!group->cost_map[j].inv_vars
|| bitmap_empty_p (group->cost_map[j].inv_vars))
fprintf (dump_file, "NIL;\n");
else
bitmap_print (dump_file,
group->cost_map[j].inv_vars, "", "\n");
}
fprintf (dump_file, "\n");
}
fprintf (dump_file, "\n");
}
}
/* Determines cost of the candidate CAND. */
static void
determine_iv_cost (struct ivopts_data *data, struct iv_cand *cand)
{
comp_cost cost_base;
int64_t cost, cost_step;
tree base;
gcc_assert (cand->iv != NULL);
/* There are two costs associated with the candidate -- its increment
and its initialization. The second is almost negligible for any loop
that rolls enough, so we take it just very little into account. */
base = cand->iv->base;
cost_base = force_var_cost (data, base, NULL);
/* It will be exceptional that the iv register happens to be initialized with
the proper value at no cost. In general, there will at least be a regcopy
or a const set. */
if (cost_base.cost == 0)
cost_base.cost = COSTS_N_INSNS (1);
/* Doloop decrement should be considered as zero cost. */
if (cand->doloop_p)
cost_step = 0;
else
cost_step = add_cost (data->speed, TYPE_MODE (TREE_TYPE (base)));
cost = cost_step + adjust_setup_cost (data, cost_base.cost);
/* Prefer the original ivs unless we may gain something by replacing it.
The reason is to make debugging simpler; so this is not relevant for
artificial ivs created by other optimization passes. */
if ((cand->pos != IP_ORIGINAL
|| !SSA_NAME_VAR (cand->var_before)
|| DECL_ARTIFICIAL (SSA_NAME_VAR (cand->var_before)))
/* Prefer doloop as well. */
&& !cand->doloop_p)
cost++;
/* Prefer not to insert statements into latch unless there are some
already (so that we do not create unnecessary jumps). */
if (cand->pos == IP_END
&& empty_block_p (ip_end_pos (data->current_loop)))
cost++;
cand->cost = cost;
cand->cost_step = cost_step;
}
/* Determines costs of computation of the candidates. */
static void
determine_iv_costs (struct ivopts_data *data)
{
unsigned i;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "<Candidate Costs>:\n");
fprintf (dump_file, " cand\tcost\n");
}
for (i = 0; i < data->vcands.length (); i++)
{
struct iv_cand *cand = data->vcands[i];
determine_iv_cost (data, cand);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " %d\t%d\n", i, cand->cost);
}
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "\n");
}
/* Estimate register pressure for loop having N_INVS invariants and N_CANDS
induction variables. Note N_INVS includes both invariant variables and
invariant expressions. */
static unsigned
ivopts_estimate_reg_pressure (struct ivopts_data *data, unsigned n_invs,
unsigned n_cands)
{
unsigned cost;
unsigned n_old = data->regs_used, n_new = n_invs + n_cands;
unsigned regs_needed = n_new + n_old, available_regs = target_avail_regs;
bool speed = data->speed;
/* If there is a call in the loop body, the call-clobbered registers
are not available for loop invariants. */
if (data->body_includes_call)
available_regs = available_regs - target_clobbered_regs;
/* If we have enough registers. */
if (regs_needed + target_res_regs < available_regs)
cost = n_new;
/* If close to running out of registers, try to preserve them. */
else if (regs_needed <= available_regs)
cost = target_reg_cost [speed] * regs_needed;
/* If we run out of available registers but the number of candidates
does not, we penalize extra registers using target_spill_cost. */
else if (n_cands <= available_regs)
cost = target_reg_cost [speed] * available_regs
+ target_spill_cost [speed] * (regs_needed - available_regs);
/* If the number of candidates runs out available registers, we penalize
extra candidate registers using target_spill_cost * 2. Because it is
more expensive to spill induction variable than invariant. */
else
cost = target_reg_cost [speed] * available_regs
+ target_spill_cost [speed] * (n_cands - available_regs) * 2
+ target_spill_cost [speed] * (regs_needed - n_cands);
/* Finally, add the number of candidates, so that we prefer eliminating
induction variables if possible. */
return cost + n_cands;
}
/* For each size of the induction variable set determine the penalty. */
static void
determine_set_costs (struct ivopts_data *data)
{
unsigned j, n;
gphi *phi;
gphi_iterator psi;
tree op;
class loop *loop = data->current_loop;
bitmap_iterator bi;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "<Global Costs>:\n");
fprintf (dump_file, " target_avail_regs %d\n", target_avail_regs);
fprintf (dump_file, " target_clobbered_regs %d\n", target_clobbered_regs);
fprintf (dump_file, " target_reg_cost %d\n", target_reg_cost[data->speed]);
fprintf (dump_file, " target_spill_cost %d\n", target_spill_cost[data->speed]);
}
n = 0;
for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi))
{
phi = psi.phi ();
op = PHI_RESULT (phi);
if (virtual_operand_p (op))
continue;
if (get_iv (data, op))
continue;
if (!POINTER_TYPE_P (TREE_TYPE (op))
&& !INTEGRAL_TYPE_P (TREE_TYPE (op)))
continue;
n++;
}
EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, j, bi)
{
struct version_info *info = ver_info (data, j);
if (info->inv_id && info->has_nonlin_use)
n++;
}
data->regs_used = n;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " regs_used %d\n", n);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " cost for size:\n");
fprintf (dump_file, " ivs\tcost\n");
for (j = 0; j <= 2 * target_avail_regs; j++)
fprintf (dump_file, " %d\t%d\n", j,
ivopts_estimate_reg_pressure (data, 0, j));
fprintf (dump_file, "\n");
}
}
/* Returns true if A is a cheaper cost pair than B. */
static bool
cheaper_cost_pair (class cost_pair *a, class cost_pair *b)
{
if (!a)
return false;
if (!b)
return true;
if (a->cost < b->cost)
return true;
if (b->cost < a->cost)
return false;
/* In case the costs are the same, prefer the cheaper candidate. */
if (a->cand->cost < b->cand->cost)
return true;
return false;
}
/* Compare if A is a more expensive cost pair than B. Return 1, 0 and -1
for more expensive, equal and cheaper respectively. */
static int
compare_cost_pair (class cost_pair *a, class cost_pair *b)
{
if (cheaper_cost_pair (a, b))
return -1;
if (cheaper_cost_pair (b, a))
return 1;
return 0;
}
/* Returns candidate by that USE is expressed in IVS. */
static class cost_pair *
iv_ca_cand_for_group (class iv_ca *ivs, struct iv_group *group)
{
return ivs->cand_for_group[group->id];
}
/* Computes the cost field of IVS structure. */
static void
iv_ca_recount_cost (struct ivopts_data *data, class iv_ca *ivs)
{
comp_cost cost = ivs->cand_use_cost;
cost += ivs->cand_cost;
cost += ivopts_estimate_reg_pressure (data, ivs->n_invs, ivs->n_cands);
ivs->cost = cost;
}
/* Remove use of invariants in set INVS by decreasing counter in N_INV_USES
and IVS. */
static void
iv_ca_set_remove_invs (class iv_ca *ivs, bitmap invs, unsigned *n_inv_uses)
{
bitmap_iterator bi;
unsigned iid;
if (!invs)
return;
gcc_assert (n_inv_uses != NULL);
EXECUTE_IF_SET_IN_BITMAP (invs, 0, iid, bi)
{
n_inv_uses[iid]--;
if (n_inv_uses[iid] == 0)
ivs->n_invs--;
}
}
/* Set USE not to be expressed by any candidate in IVS. */
static void
iv_ca_set_no_cp (struct ivopts_data *data, class iv_ca *ivs,
struct iv_group *group)
{
unsigned gid = group->id, cid;
class cost_pair *cp;
cp = ivs->cand_for_group[gid];
if (!cp)
return;
cid = cp->cand->id;
ivs->bad_groups++;
ivs->cand_for_group[gid] = NULL;
ivs->n_cand_uses[cid]--;
if (ivs->n_cand_uses[cid] == 0)
{
bitmap_clear_bit (ivs->cands, cid);
if (!cp->cand->doloop_p || !targetm.have_count_reg_decr_p)
ivs->n_cands--;
ivs->cand_cost -= cp->cand->cost;
iv_ca_set_remove_invs (ivs, cp->cand->inv_vars, ivs->n_inv_var_uses);
iv_ca_set_remove_invs (ivs, cp->cand->inv_exprs, ivs->n_inv_expr_uses);
}
ivs->cand_use_cost -= cp->cost;
iv_ca_set_remove_invs (ivs, cp->inv_vars, ivs->n_inv_var_uses);
iv_ca_set_remove_invs (ivs, cp->inv_exprs, ivs->n_inv_expr_uses);
iv_ca_recount_cost (data, ivs);
}
/* Add use of invariants in set INVS by increasing counter in N_INV_USES and
IVS. */
static void
iv_ca_set_add_invs (class iv_ca *ivs, bitmap invs, unsigned *n_inv_uses)
{
bitmap_iterator bi;
unsigned iid;
if (!invs)
return;
gcc_assert (n_inv_uses != NULL);
EXECUTE_IF_SET_IN_BITMAP (invs, 0, iid, bi)
{
n_inv_uses[iid]++;
if (n_inv_uses[iid] == 1)
ivs->n_invs++;
}
}
/* Set cost pair for GROUP in set IVS to CP. */
static void
iv_ca_set_cp (struct ivopts_data *data, class iv_ca *ivs,
struct iv_group *group, class cost_pair *cp)
{
unsigned gid = group->id, cid;
if (ivs->cand_for_group[gid] == cp)
return;
if (ivs->cand_for_group[gid])
iv_ca_set_no_cp (data, ivs, group);
if (cp)
{
cid = cp->cand->id;
ivs->bad_groups--;
ivs->cand_for_group[gid] = cp;
ivs->n_cand_uses[cid]++;
if (ivs->n_cand_uses[cid] == 1)
{
bitmap_set_bit (ivs->cands, cid);
if (!cp->cand->doloop_p || !targetm.have_count_reg_decr_p)
ivs->n_cands++;
ivs->cand_cost += cp->cand->cost;
iv_ca_set_add_invs (ivs, cp->cand->inv_vars, ivs->n_inv_var_uses);
iv_ca_set_add_invs (ivs, cp->cand->inv_exprs, ivs->n_inv_expr_uses);
}
ivs->cand_use_cost += cp->cost;
iv_ca_set_add_invs (ivs, cp->inv_vars, ivs->n_inv_var_uses);
iv_ca_set_add_invs (ivs, cp->inv_exprs, ivs->n_inv_expr_uses);
iv_ca_recount_cost (data, ivs);
}
}
/* Extend set IVS by expressing USE by some of the candidates in it
if possible. Consider all important candidates if candidates in
set IVS don't give any result. */
static void
iv_ca_add_group (struct ivopts_data *data, class iv_ca *ivs,
struct iv_group *group)
{
class cost_pair *best_cp = NULL, *cp;
bitmap_iterator bi;
unsigned i;
struct iv_cand *cand;
gcc_assert (ivs->upto >= group->id);
ivs->upto++;
ivs->bad_groups++;
EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi)
{
cand = data->vcands[i];
cp = get_group_iv_cost (data, group, cand);
if (cheaper_cost_pair (cp, best_cp))
best_cp = cp;
}
if (best_cp == NULL)
{
EXECUTE_IF_SET_IN_BITMAP (data->important_candidates, 0, i, bi)
{
cand = data->vcands[i];
cp = get_group_iv_cost (data, group, cand);
if (cheaper_cost_pair (cp, best_cp))
best_cp = cp;
}
}
iv_ca_set_cp (data, ivs, group, best_cp);
}
/* Get cost for assignment IVS. */
static comp_cost
iv_ca_cost (class iv_ca *ivs)
{
/* This was a conditional expression but it triggered a bug in
Sun C 5.5. */
if (ivs->bad_groups)
return infinite_cost;
else
return ivs->cost;
}
/* Compare if applying NEW_CP to GROUP for IVS introduces more invariants
than OLD_CP. Return 1, 0 and -1 for more, equal and fewer invariants
respectively. */
static int
iv_ca_compare_deps (struct ivopts_data *data, class iv_ca *ivs,
struct iv_group *group, class cost_pair *old_cp,
class cost_pair *new_cp)
{
gcc_assert (old_cp && new_cp && old_cp != new_cp);
unsigned old_n_invs = ivs->n_invs;
iv_ca_set_cp (data, ivs, group, new_cp);
unsigned new_n_invs = ivs->n_invs;
iv_ca_set_cp (data, ivs, group, old_cp);
return new_n_invs > old_n_invs ? 1 : (new_n_invs < old_n_invs ? -1 : 0);
}
/* Creates change of expressing GROUP by NEW_CP instead of OLD_CP and chains
it before NEXT. */
static struct iv_ca_delta *
iv_ca_delta_add (struct iv_group *group, class cost_pair *old_cp,
class cost_pair *new_cp, struct iv_ca_delta *next)
{
struct iv_ca_delta *change = XNEW (struct iv_ca_delta);
change->group = group;
change->old_cp = old_cp;
change->new_cp = new_cp;
change->next = next;
return change;
}
/* Joins two lists of changes L1 and L2. Destructive -- old lists
are rewritten. */
static struct iv_ca_delta *
iv_ca_delta_join (struct iv_ca_delta *l1, struct iv_ca_delta *l2)
{
struct iv_ca_delta *last;
if (!l2)
return l1;
if (!l1)
return l2;
for (last = l1; last->next; last = last->next)
continue;
last->next = l2;
return l1;
}
/* Reverse the list of changes DELTA, forming the inverse to it. */
static struct iv_ca_delta *
iv_ca_delta_reverse (struct iv_ca_delta *delta)
{
struct iv_ca_delta *act, *next, *prev = NULL;
for (act = delta; act; act = next)
{
next = act->next;
act->next = prev;
prev = act;
std::swap (act->old_cp, act->new_cp);
}
return prev;
}
/* Commit changes in DELTA to IVS. If FORWARD is false, the changes are
reverted instead. */
static void
iv_ca_delta_commit (struct ivopts_data *data, class iv_ca *ivs,
struct iv_ca_delta *delta, bool forward)
{
class cost_pair *from, *to;
struct iv_ca_delta *act;
if (!forward)
delta = iv_ca_delta_reverse (delta);
for (act = delta; act; act = act->next)
{
from = act->old_cp;
to = act->new_cp;
gcc_assert (iv_ca_cand_for_group (ivs, act->group) == from);
iv_ca_set_cp (data, ivs, act->group, to);
}
if (!forward)
iv_ca_delta_reverse (delta);
}
/* Returns true if CAND is used in IVS. */
static bool
iv_ca_cand_used_p (class iv_ca *ivs, struct iv_cand *cand)
{
return ivs->n_cand_uses[cand->id] > 0;
}
/* Returns number of induction variable candidates in the set IVS. */
static unsigned
iv_ca_n_cands (class iv_ca *ivs)
{
return ivs->n_cands;
}
/* Free the list of changes DELTA. */
static void
iv_ca_delta_free (struct iv_ca_delta **delta)
{
struct iv_ca_delta *act, *next;
for (act = *delta; act; act = next)
{
next = act->next;
free (act);
}
*delta = NULL;
}
/* Allocates new iv candidates assignment. */
static class iv_ca *
iv_ca_new (struct ivopts_data *data)
{
class iv_ca *nw = XNEW (class iv_ca);
nw->upto = 0;
nw->bad_groups = 0;
nw->cand_for_group = XCNEWVEC (class cost_pair *,
data->vgroups.length ());
nw->n_cand_uses = XCNEWVEC (unsigned, data->vcands.length ());
nw->cands = BITMAP_ALLOC (NULL);
nw->n_cands = 0;
nw->n_invs = 0;
nw->cand_use_cost = no_cost;
nw->cand_cost = 0;
nw->n_inv_var_uses = XCNEWVEC (unsigned, data->max_inv_var_id + 1);
nw->n_inv_expr_uses = XCNEWVEC (unsigned, data->max_inv_expr_id + 1);
nw->cost = no_cost;
return nw;
}
/* Free memory occupied by the set IVS. */
static void
iv_ca_free (class iv_ca **ivs)
{
free ((*ivs)->cand_for_group);
free ((*ivs)->n_cand_uses);
BITMAP_FREE ((*ivs)->cands);
free ((*ivs)->n_inv_var_uses);
free ((*ivs)->n_inv_expr_uses);
free (*ivs);
*ivs = NULL;
}
/* Dumps IVS to FILE. */
static void
iv_ca_dump (struct ivopts_data *data, FILE *file, class iv_ca *ivs)
{
unsigned i;
comp_cost cost = iv_ca_cost (ivs);
fprintf (file, " cost: %" PRId64 " (complexity %d)\n", cost.cost,
cost.complexity);
fprintf (file, " reg_cost: %d\n",
ivopts_estimate_reg_pressure (data, ivs->n_invs, ivs->n_cands));
fprintf (file, " cand_cost: %" PRId64 "\n cand_group_cost: "
"%" PRId64 " (complexity %d)\n", ivs->cand_cost,
ivs->cand_use_cost.cost, ivs->cand_use_cost.complexity);
bitmap_print (file, ivs->cands, " candidates: ","\n");
for (i = 0; i < ivs->upto; i++)
{
struct iv_group *group = data->vgroups[i];
class cost_pair *cp = iv_ca_cand_for_group (ivs, group);
if (cp)
fprintf (file, " group:%d --> iv_cand:%d, cost=("
"%" PRId64 ",%d)\n", group->id, cp->cand->id,
cp->cost.cost, cp->cost.complexity);
else
fprintf (file, " group:%d --> ??\n", group->id);
}
const char *pref = "";
fprintf (file, " invariant variables: ");
for (i = 1; i <= data->max_inv_var_id; i++)
if (ivs->n_inv_var_uses[i])
{
fprintf (file, "%s%d", pref, i);
pref = ", ";
}
pref = "";
fprintf (file, "\n invariant expressions: ");
for (i = 1; i <= data->max_inv_expr_id; i++)
if (ivs->n_inv_expr_uses[i])
{
fprintf (file, "%s%d", pref, i);
pref = ", ";
}
fprintf (file, "\n\n");
}
/* Try changing candidate in IVS to CAND for each use. Return cost of the
new set, and store differences in DELTA. Number of induction variables
in the new set is stored to N_IVS. MIN_NCAND is a flag. When it is true
the function will try to find a solution with mimimal iv candidates. */
static comp_cost
iv_ca_extend (struct ivopts_data *data, class iv_ca *ivs,
struct iv_cand *cand, struct iv_ca_delta **delta,
unsigned *n_ivs, bool min_ncand)
{
unsigned i;
comp_cost cost;
struct iv_group *group;
class cost_pair *old_cp, *new_cp;
*delta = NULL;
for (i = 0; i < ivs->upto; i++)
{
group = data->vgroups[i];
old_cp = iv_ca_cand_for_group (ivs, group);
if (old_cp
&& old_cp->cand == cand)
continue;
new_cp = get_group_iv_cost (data, group, cand);
if (!new_cp)
continue;
if (!min_ncand)
{
int cmp_invs = iv_ca_compare_deps (data, ivs, group, old_cp, new_cp);
/* Skip if new_cp depends on more invariants. */
if (cmp_invs > 0)
continue;
int cmp_cost = compare_cost_pair (new_cp, old_cp);
/* Skip if new_cp is not cheaper. */
if (cmp_cost > 0 || (cmp_cost == 0 && cmp_invs == 0))
continue;
}
*delta = iv_ca_delta_add (group, old_cp, new_cp, *delta);
}
iv_ca_delta_commit (data, ivs, *delta, true);
cost = iv_ca_cost (ivs);
if (n_ivs)
*n_ivs = iv_ca_n_cands (ivs);
iv_ca_delta_commit (data, ivs, *delta, false);
return cost;
}
/* Try narrowing set IVS by removing CAND. Return the cost of
the new set and store the differences in DELTA. START is
the candidate with which we start narrowing. */
static comp_cost
iv_ca_narrow (struct ivopts_data *data, class iv_ca *ivs,
struct iv_cand *cand, struct iv_cand *start,
struct iv_ca_delta **delta)
{
unsigned i, ci;
struct iv_group *group;
class cost_pair *old_cp, *new_cp, *cp;
bitmap_iterator bi;
struct iv_cand *cnd;
comp_cost cost, best_cost, acost;
*delta = NULL;
for (i = 0; i < data->vgroups.length (); i++)
{
group = data->vgroups[i];
old_cp = iv_ca_cand_for_group (ivs, group);
if (old_cp->cand != cand)
continue;
best_cost = iv_ca_cost (ivs);
/* Start narrowing with START. */
new_cp = get_group_iv_cost (data, group, start);
if (data->consider_all_candidates)
{
EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, ci, bi)
{
if (ci == cand->id || (start && ci == start->id))
continue;
cnd = data->vcands[ci];
cp = get_group_iv_cost (data, group, cnd);
if (!cp)
continue;
iv_ca_set_cp (data, ivs, group, cp);
acost = iv_ca_cost (ivs);
if (acost < best_cost)
{
best_cost = acost;
new_cp = cp;
}
}
}
else
{
EXECUTE_IF_AND_IN_BITMAP (group->related_cands, ivs->cands, 0, ci, bi)
{
if (ci == cand->id || (start && ci == start->id))
continue;
cnd = data->vcands[ci];
cp = get_group_iv_cost (data, group, cnd);
if (!cp)
continue;
iv_ca_set_cp (data, ivs, group, cp);
acost = iv_ca_cost (ivs);
if (acost < best_cost)
{
best_cost = acost;
new_cp = cp;
}
}
}
/* Restore to old cp for use. */
iv_ca_set_cp (data, ivs, group, old_cp);
if (!new_cp)
{
iv_ca_delta_free (delta);
return infinite_cost;
}
*delta = iv_ca_delta_add (group, old_cp, new_cp, *delta);
}
iv_ca_delta_commit (data, ivs, *delta, true);
cost = iv_ca_cost (ivs);
iv_ca_delta_commit (data, ivs, *delta, false);
return cost;
}
/* Try optimizing the set of candidates IVS by removing candidates different
from to EXCEPT_CAND from it. Return cost of the new set, and store
differences in DELTA. */
static comp_cost
iv_ca_prune (struct ivopts_data *data, class iv_ca *ivs,
struct iv_cand *except_cand, struct iv_ca_delta **delta)
{
bitmap_iterator bi;
struct iv_ca_delta *act_delta, *best_delta;
unsigned i;
comp_cost best_cost, acost;
struct iv_cand *cand;
best_delta = NULL;
best_cost = iv_ca_cost (ivs);
EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi)
{
cand = data->vcands[i];
if (cand == except_cand)
continue;
acost = iv_ca_narrow (data, ivs, cand, except_cand, &act_delta);
if (acost < best_cost)
{
best_cost = acost;
iv_ca_delta_free (&best_delta);
best_delta = act_delta;
}
else
iv_ca_delta_free (&act_delta);
}
if (!best_delta)
{
*delta = NULL;
return best_cost;
}
/* Recurse to possibly remove other unnecessary ivs. */
iv_ca_delta_commit (data, ivs, best_delta, true);
best_cost = iv_ca_prune (data, ivs, except_cand, delta);
iv_ca_delta_commit (data, ivs, best_delta, false);
*delta = iv_ca_delta_join (best_delta, *delta);
return best_cost;
}
/* Check if CAND_IDX is a candidate other than OLD_CAND and has
cheaper local cost for GROUP than BEST_CP. Return pointer to
the corresponding cost_pair, otherwise just return BEST_CP. */
static class cost_pair*
cheaper_cost_with_cand (struct ivopts_data *data, struct iv_group *group,
unsigned int cand_idx, struct iv_cand *old_cand,
class cost_pair *best_cp)
{
struct iv_cand *cand;
class cost_pair *cp;
gcc_assert (old_cand != NULL && best_cp != NULL);
if (cand_idx == old_cand->id)
return best_cp;
cand = data->vcands[cand_idx];
cp = get_group_iv_cost (data, group, cand);
if (cp != NULL && cheaper_cost_pair (cp, best_cp))
return cp;
return best_cp;
}
/* Try breaking local optimal fixed-point for IVS by replacing candidates
which are used by more than one iv uses. For each of those candidates,
this function tries to represent iv uses under that candidate using
other ones with lower local cost, then tries to prune the new set.
If the new set has lower cost, It returns the new cost after recording
candidate replacement in list DELTA. */
static comp_cost
iv_ca_replace (struct ivopts_data *data, class iv_ca *ivs,
struct iv_ca_delta **delta)
{
bitmap_iterator bi, bj;
unsigned int i, j, k;
struct iv_cand *cand;
comp_cost orig_cost, acost;
struct iv_ca_delta *act_delta, *tmp_delta;
class cost_pair *old_cp, *best_cp = NULL;
*delta = NULL;
orig_cost = iv_ca_cost (ivs);
EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi)
{
if (ivs->n_cand_uses[i] == 1
|| ivs->n_cand_uses[i] > ALWAYS_PRUNE_CAND_SET_BOUND)
continue;
cand = data->vcands[i];
act_delta = NULL;
/* Represent uses under current candidate using other ones with
lower local cost. */
for (j = 0; j < ivs->upto; j++)
{
struct iv_group *group = data->vgroups[j];
old_cp = iv_ca_cand_for_group (ivs, group);
if (old_cp->cand != cand)
continue;
best_cp = old_cp;
if (data->consider_all_candidates)
for (k = 0; k < data->vcands.length (); k++)
best_cp = cheaper_cost_with_cand (data, group, k,
old_cp->cand, best_cp);
else
EXECUTE_IF_SET_IN_BITMAP (group->related_cands, 0, k, bj)
best_cp = cheaper_cost_with_cand (data, group, k,
old_cp->cand, best_cp);
if (best_cp == old_cp)
continue;
act_delta = iv_ca_delta_add (group, old_cp, best_cp, act_delta);
}
/* No need for further prune. */
if (!act_delta)
continue;
/* Prune the new candidate set. */
iv_ca_delta_commit (data, ivs, act_delta, true);
acost = iv_ca_prune (data, ivs, NULL, &tmp_delta);
iv_ca_delta_commit (data, ivs, act_delta, false);
act_delta = iv_ca_delta_join (act_delta, tmp_delta);
if (acost < orig_cost)
{
*delta = act_delta;
return acost;
}
else
iv_ca_delta_free (&act_delta);
}
return orig_cost;
}
/* Tries to extend the sets IVS in the best possible way in order to
express the GROUP. If ORIGINALP is true, prefer candidates from
the original set of IVs, otherwise favor important candidates not
based on any memory object. */
static bool
try_add_cand_for (struct ivopts_data *data, class iv_ca *ivs,
struct iv_group *group, bool originalp)
{
comp_cost best_cost, act_cost;
unsigned i;
bitmap_iterator bi;
struct iv_cand *cand;
struct iv_ca_delta *best_delta = NULL, *act_delta;
class cost_pair *cp;
iv_ca_add_group (data, ivs, group);
best_cost = iv_ca_cost (ivs);
cp = iv_ca_cand_for_group (ivs, group);
if (cp)
{
best_delta = iv_ca_delta_add (group, NULL, cp, NULL);
iv_ca_set_no_cp (data, ivs, group);
}
/* If ORIGINALP is true, try to find the original IV for the use. Otherwise
first try important candidates not based on any memory object. Only if
this fails, try the specific ones. Rationale -- in loops with many
variables the best choice often is to use just one generic biv. If we
added here many ivs specific to the uses, the optimization algorithm later
would be likely to get stuck in a local minimum, thus causing us to create
too many ivs. The approach from few ivs to more seems more likely to be
successful -- starting from few ivs, replacing an expensive use by a
specific iv should always be a win. */
EXECUTE_IF_SET_IN_BITMAP (group->related_cands, 0, i, bi)
{
cand = data->vcands[i];
if (originalp && cand->pos !=IP_ORIGINAL)
continue;
if (!originalp && cand->iv->base_object != NULL_TREE)
continue;
if (iv_ca_cand_used_p (ivs, cand))
continue;
cp = get_group_iv_cost (data, group, cand);
if (!cp)
continue;
iv_ca_set_cp (data, ivs, group, cp);
act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL,
true);
iv_ca_set_no_cp (data, ivs, group);
act_delta = iv_ca_delta_add (group, NULL, cp, act_delta);
if (act_cost < best_cost)
{
best_cost = act_cost;
iv_ca_delta_free (&best_delta);
best_delta = act_delta;
}
else
iv_ca_delta_free (&act_delta);
}
if (best_cost.infinite_cost_p ())
{
for (i = 0; i < group->n_map_members; i++)
{
cp = group->cost_map + i;
cand = cp->cand;
if (!cand)
continue;
/* Already tried this. */
if (cand->important)
{
if (originalp && cand->pos == IP_ORIGINAL)
continue;
if (!originalp && cand->iv->base_object == NULL_TREE)
continue;
}
if (iv_ca_cand_used_p (ivs, cand))
continue;
act_delta = NULL;
iv_ca_set_cp (data, ivs, group, cp);
act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL, true);
iv_ca_set_no_cp (data, ivs, group);
act_delta = iv_ca_delta_add (group,
iv_ca_cand_for_group (ivs, group),
cp, act_delta);
if (act_cost < best_cost)
{
best_cost = act_cost;
if (best_delta)
iv_ca_delta_free (&best_delta);
best_delta = act_delta;
}
else
iv_ca_delta_free (&act_delta);
}
}
iv_ca_delta_commit (data, ivs, best_delta, true);
iv_ca_delta_free (&best_delta);
return !best_cost.infinite_cost_p ();
}
/* Finds an initial assignment of candidates to uses. */
static class iv_ca *
get_initial_solution (struct ivopts_data *data, bool originalp)
{
unsigned i;
class iv_ca *ivs = iv_ca_new (data);
for (i = 0; i < data->vgroups.length (); i++)
if (!try_add_cand_for (data, ivs, data->vgroups[i], originalp))
{
iv_ca_free (&ivs);
return NULL;
}
return ivs;
}
/* Tries to improve set of induction variables IVS. TRY_REPLACE_P
points to a bool variable, this function tries to break local
optimal fixed-point by replacing candidates in IVS if it's true. */
static bool
try_improve_iv_set (struct ivopts_data *data,
class iv_ca *ivs, bool *try_replace_p)
{
unsigned i, n_ivs;
comp_cost acost, best_cost = iv_ca_cost (ivs);
struct iv_ca_delta *best_delta = NULL, *act_delta, *tmp_delta;
struct iv_cand *cand;
/* Try extending the set of induction variables by one. */
for (i = 0; i < data->vcands.length (); i++)
{
cand = data->vcands[i];
if (iv_ca_cand_used_p (ivs, cand))
continue;
acost = iv_ca_extend (data, ivs, cand, &act_delta, &n_ivs, false);
if (!act_delta)
continue;
/* If we successfully added the candidate and the set is small enough,
try optimizing it by removing other candidates. */
if (n_ivs <= ALWAYS_PRUNE_CAND_SET_BOUND)
{
iv_ca_delta_commit (data, ivs, act_delta, true);
acost = iv_ca_prune (data, ivs, cand, &tmp_delta);
iv_ca_delta_commit (data, ivs, act_delta, false);
act_delta = iv_ca_delta_join (act_delta, tmp_delta);
}
if (acost < best_cost)
{
best_cost = acost;
iv_ca_delta_free (&best_delta);
best_delta = act_delta;
}
else
iv_ca_delta_free (&act_delta);
}
if (!best_delta)
{
/* Try removing the candidates from the set instead. */
best_cost = iv_ca_prune (data, ivs, NULL, &best_delta);
if (!best_delta && *try_replace_p)
{
*try_replace_p = false;
/* So far candidate selecting algorithm tends to choose fewer IVs
so that it can handle cases in which loops have many variables
but the best choice is often to use only one general biv. One
weakness is it can't handle opposite cases, in which different
candidates should be chosen with respect to each use. To solve
the problem, we replace candidates in a manner described by the
comments of iv_ca_replace, thus give general algorithm a chance
to break local optimal fixed-point in these cases. */
best_cost = iv_ca_replace (data, ivs, &best_delta);
}
if (!best_delta)
return false;
}
iv_ca_delta_commit (data, ivs, best_delta, true);
iv_ca_delta_free (&best_delta);
return best_cost == iv_ca_cost (ivs);
}
/* Attempts to find the optimal set of induction variables. We do simple
greedy heuristic -- we try to replace at most one candidate in the selected
solution and remove the unused ivs while this improves the cost. */
static class iv_ca *
find_optimal_iv_set_1 (struct ivopts_data *data, bool originalp)
{
class iv_ca *set;
bool try_replace_p = true;
/* Get the initial solution. */
set = get_initial_solution (data, originalp);
if (!set)
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Unable to substitute for ivs, failed.\n");
return NULL;
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Initial set of candidates:\n");
iv_ca_dump (data, dump_file, set);
}
while (try_improve_iv_set (data, set, &try_replace_p))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Improved to:\n");
iv_ca_dump (data, dump_file, set);
}
}
/* If the set has infinite_cost, it can't be optimal. */
if (iv_ca_cost (set).infinite_cost_p ())
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Overflow to infinite cost in try_improve_iv_set.\n");
iv_ca_free (&set);
}
return set;
}
static class iv_ca *
find_optimal_iv_set (struct ivopts_data *data)
{
unsigned i;
comp_cost cost, origcost;
class iv_ca *set, *origset;
/* Determine the cost based on a strategy that starts with original IVs,
and try again using a strategy that prefers candidates not based
on any IVs. */
origset = find_optimal_iv_set_1 (data, true);
set = find_optimal_iv_set_1 (data, false);
if (!origset && !set)
return NULL;
origcost = origset ? iv_ca_cost (origset) : infinite_cost;
cost = set ? iv_ca_cost (set) : infinite_cost;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Original cost %" PRId64 " (complexity %d)\n\n",
origcost.cost, origcost.complexity);
fprintf (dump_file, "Final cost %" PRId64 " (complexity %d)\n\n",
cost.cost, cost.complexity);
}
/* Choose the one with the best cost. */
if (origcost <= cost)
{
if (set)
iv_ca_free (&set);
set = origset;
}
else if (origset)
iv_ca_free (&origset);
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
group->selected = iv_ca_cand_for_group (set, group)->cand;
}
return set;
}
/* Creates a new induction variable corresponding to CAND. */
static void
create_new_iv (struct ivopts_data *data, struct iv_cand *cand)
{
gimple_stmt_iterator incr_pos;
tree base;
struct iv_use *use;
struct iv_group *group;
bool after = false;
gcc_assert (cand->iv != NULL);
switch (cand->pos)
{
case IP_NORMAL:
incr_pos = gsi_last_bb (ip_normal_pos (data->current_loop));
break;
case IP_END:
incr_pos = gsi_last_bb (ip_end_pos (data->current_loop));
after = true;
break;
case IP_AFTER_USE:
after = true;
/* fall through */
case IP_BEFORE_USE:
incr_pos = gsi_for_stmt (cand->incremented_at);
break;
case IP_ORIGINAL:
/* Mark that the iv is preserved. */
name_info (data, cand->var_before)->preserve_biv = true;
name_info (data, cand->var_after)->preserve_biv = true;
/* Rewrite the increment so that it uses var_before directly. */
use = find_interesting_uses_op (data, cand->var_after);
group = data->vgroups[use->group_id];
group->selected = cand;
return;
}
gimple_add_tmp_var (cand->var_before);
base = unshare_expr (cand->iv->base);
create_iv (base, unshare_expr (cand->iv->step),
cand->var_before, data->current_loop,
&incr_pos, after, &cand->var_before, &cand->var_after);
}
/* Creates new induction variables described in SET. */
static void
create_new_ivs (struct ivopts_data *data, class iv_ca *set)
{
unsigned i;
struct iv_cand *cand;
bitmap_iterator bi;
EXECUTE_IF_SET_IN_BITMAP (set->cands, 0, i, bi)
{
cand = data->vcands[i];
create_new_iv (data, cand);
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Selected IV set for loop %d",
data->current_loop->num);
if (data->loop_loc != UNKNOWN_LOCATION)
fprintf (dump_file, " at %s:%d", LOCATION_FILE (data->loop_loc),
LOCATION_LINE (data->loop_loc));
fprintf (dump_file, ", " HOST_WIDE_INT_PRINT_DEC " avg niters",
avg_loop_niter (data->current_loop));
fprintf (dump_file, ", %lu IVs:\n", bitmap_count_bits (set->cands));
EXECUTE_IF_SET_IN_BITMAP (set->cands, 0, i, bi)
{
cand = data->vcands[i];
dump_cand (dump_file, cand);
}
fprintf (dump_file, "\n");
}
}
/* Rewrites USE (definition of iv used in a nonlinear expression)
using candidate CAND. */
static void
rewrite_use_nonlinear_expr (struct ivopts_data *data,
struct iv_use *use, struct iv_cand *cand)
{
gassign *ass;
gimple_stmt_iterator bsi;
tree comp, type = get_use_type (use), tgt;
/* An important special case -- if we are asked to express value of
the original iv by itself, just exit; there is no need to
introduce a new computation (that might also need casting the
variable to unsigned and back). */
if (cand->pos == IP_ORIGINAL
&& cand->incremented_at == use->stmt)
{
tree op = NULL_TREE;
enum tree_code stmt_code;
gcc_assert (is_gimple_assign (use->stmt));
gcc_assert (gimple_assign_lhs (use->stmt) == cand->var_after);
/* Check whether we may leave the computation unchanged.
This is the case only if it does not rely on other
computations in the loop -- otherwise, the computation
we rely upon may be removed in remove_unused_ivs,
thus leading to ICE. */
stmt_code = gimple_assign_rhs_code (use->stmt);
if (stmt_code == PLUS_EXPR
|| stmt_code == MINUS_EXPR
|| stmt_code == POINTER_PLUS_EXPR)
{
if (gimple_assign_rhs1 (use->stmt) == cand->var_before)
op = gimple_assign_rhs2 (use->stmt);
else if (gimple_assign_rhs2 (use->stmt) == cand->var_before)
op = gimple_assign_rhs1 (use->stmt);
}
if (op != NULL_TREE)
{
if (expr_invariant_in_loop_p (data->current_loop, op))
return;
if (TREE_CODE (op) == SSA_NAME)
{
struct iv *iv = get_iv (data, op);
if (iv != NULL && integer_zerop (iv->step))
return;
}
}
}
switch (gimple_code (use->stmt))
{
case GIMPLE_PHI:
tgt = PHI_RESULT (use->stmt);
/* If we should keep the biv, do not replace it. */
if (name_info (data, tgt)->preserve_biv)
return;
bsi = gsi_after_labels (gimple_bb (use->stmt));
break;
case GIMPLE_ASSIGN:
tgt = gimple_assign_lhs (use->stmt);
bsi = gsi_for_stmt (use->stmt);
break;
default:
gcc_unreachable ();
}
aff_tree aff_inv, aff_var;
if (!get_computation_aff_1 (data->current_loop, use->stmt,
use, cand, &aff_inv, &aff_var))
gcc_unreachable ();
unshare_aff_combination (&aff_inv);
unshare_aff_combination (&aff_var);
/* Prefer CSE opportunity than loop invariant by adding offset at last
so that iv_uses have different offsets can be CSEed. */
poly_widest_int offset = aff_inv.offset;
aff_inv.offset = 0;
gimple_seq stmt_list = NULL, seq = NULL;
tree comp_op1 = aff_combination_to_tree (&aff_inv);
tree comp_op2 = aff_combination_to_tree (&aff_var);
gcc_assert (comp_op1 && comp_op2);
comp_op1 = force_gimple_operand (comp_op1, &seq, true, NULL);
gimple_seq_add_seq (&stmt_list, seq);
comp_op2 = force_gimple_operand (comp_op2, &seq, true, NULL);
gimple_seq_add_seq (&stmt_list, seq);
if (POINTER_TYPE_P (TREE_TYPE (comp_op2)))
std::swap (comp_op1, comp_op2);
if (POINTER_TYPE_P (TREE_TYPE (comp_op1)))
{
comp = fold_build_pointer_plus (comp_op1,
fold_convert (sizetype, comp_op2));
comp = fold_build_pointer_plus (comp,
wide_int_to_tree (sizetype, offset));
}
else
{
comp = fold_build2 (PLUS_EXPR, TREE_TYPE (comp_op1), comp_op1,
fold_convert (TREE_TYPE (comp_op1), comp_op2));
comp = fold_build2 (PLUS_EXPR, TREE_TYPE (comp_op1), comp,
wide_int_to_tree (TREE_TYPE (comp_op1), offset));
}
comp = fold_convert (type, comp);
comp = force_gimple_operand (comp, &seq, false, NULL);
gimple_seq_add_seq (&stmt_list, seq);
if (gimple_code (use->stmt) != GIMPLE_PHI
/* We can't allow re-allocating the stmt as it might be pointed
to still. */
&& (get_gimple_rhs_num_ops (TREE_CODE (comp))
>= gimple_num_ops (gsi_stmt (bsi))))
{
comp = force_gimple_operand (comp, &seq, true, NULL);
gimple_seq_add_seq (&stmt_list, seq);
if (POINTER_TYPE_P (TREE_TYPE (tgt)))
{
duplicate_ssa_name_ptr_info (comp, SSA_NAME_PTR_INFO (tgt));
/* As this isn't a plain copy we have to reset alignment
information. */
if (SSA_NAME_PTR_INFO (comp))
mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (comp));
}
}
gsi_insert_seq_before (&bsi, stmt_list, GSI_SAME_STMT);
if (gimple_code (use->stmt) == GIMPLE_PHI)
{
ass = gimple_build_assign (tgt, comp);
gsi_insert_before (&bsi, ass, GSI_SAME_STMT);
bsi = gsi_for_stmt (use->stmt);
remove_phi_node (&bsi, false);
}
else
{
gimple_assign_set_rhs_from_tree (&bsi, comp);
use->stmt = gsi_stmt (bsi);
}
}
/* Performs a peephole optimization to reorder the iv update statement with
a mem ref to enable instruction combining in later phases. The mem ref uses
the iv value before the update, so the reordering transformation requires
adjustment of the offset. CAND is the selected IV_CAND.
Example:
t = MEM_REF (base, iv1, 8, 16); // base, index, stride, offset
iv2 = iv1 + 1;
if (t < val) (1)
goto L;
goto Head;
directly propagating t over to (1) will introduce overlapping live range
thus increase register pressure. This peephole transform it into:
iv2 = iv1 + 1;
t = MEM_REF (base, iv2, 8, 8);
if (t < val)
goto L;
goto Head;
*/
static void
adjust_iv_update_pos (struct iv_cand *cand, struct iv_use *use)
{
tree var_after;
gimple *iv_update, *stmt;
basic_block bb;
gimple_stmt_iterator gsi, gsi_iv;
if (cand->pos != IP_NORMAL)
return;
var_after = cand->var_after;
iv_update = SSA_NAME_DEF_STMT (var_after);
bb = gimple_bb (iv_update);
gsi = gsi_last_nondebug_bb (bb);
stmt = gsi_stmt (gsi);
/* Only handle conditional statement for now. */
if (gimple_code (stmt) != GIMPLE_COND)
return;
gsi_prev_nondebug (&gsi);
stmt = gsi_stmt (gsi);
if (stmt != iv_update)
return;
gsi_prev_nondebug (&gsi);
if (gsi_end_p (gsi))
return;
stmt = gsi_stmt (gsi);
if (gimple_code (stmt) != GIMPLE_ASSIGN)
return;
if (stmt != use->stmt)
return;
if (TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME)
return;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Reordering \n");
print_gimple_stmt (dump_file, iv_update, 0);
print_gimple_stmt (dump_file, use->stmt, 0);
fprintf (dump_file, "\n");
}
gsi = gsi_for_stmt (use->stmt);
gsi_iv = gsi_for_stmt (iv_update);
gsi_move_before (&gsi_iv, &gsi);
cand->pos = IP_BEFORE_USE;
cand->incremented_at = use->stmt;
}
/* Return the alias pointer type that should be used for a MEM_REF
associated with USE, which has type USE_PTR_ADDRESS. */
static tree
get_alias_ptr_type_for_ptr_address (iv_use *use)
{
gcall *call = as_a <gcall *> (use->stmt);
switch (gimple_call_internal_fn (call))
{
case IFN_MASK_LOAD:
case IFN_MASK_STORE:
case IFN_MASK_LOAD_LANES:
case IFN_MASK_STORE_LANES:
case IFN_LEN_LOAD:
case IFN_LEN_STORE:
/* The second argument contains the correct alias type. */
gcc_assert (use->op_p = gimple_call_arg_ptr (call, 0));
return TREE_TYPE (gimple_call_arg (call, 1));
default:
gcc_unreachable ();
}
}
/* Rewrites USE (address that is an iv) using candidate CAND. */
static void
rewrite_use_address (struct ivopts_data *data,
struct iv_use *use, struct iv_cand *cand)
{
aff_tree aff;
bool ok;
adjust_iv_update_pos (cand, use);
ok = get_computation_aff (data->current_loop, use->stmt, use, cand, &aff);
gcc_assert (ok);
unshare_aff_combination (&aff);
/* To avoid undefined overflow problems, all IV candidates use unsigned
integer types. The drawback is that this makes it impossible for
create_mem_ref to distinguish an IV that is based on a memory object
from one that represents simply an offset.
To work around this problem, we pass a hint to create_mem_ref that
indicates which variable (if any) in aff is an IV based on a memory
object. Note that we only consider the candidate. If this is not
based on an object, the base of the reference is in some subexpression
of the use -- but these will use pointer types, so they are recognized
by the create_mem_ref heuristics anyway. */
tree iv = var_at_stmt (data->current_loop, cand, use->stmt);
tree base_hint = (cand->iv->base_object) ? iv : NULL_TREE;
gimple_stmt_iterator bsi = gsi_for_stmt (use->stmt);
tree type = use->mem_type;
tree alias_ptr_type;
if (use->type == USE_PTR_ADDRESS)
alias_ptr_type = get_alias_ptr_type_for_ptr_address (use);
else
{
gcc_assert (type == TREE_TYPE (*use->op_p));
unsigned int align = get_object_alignment (*use->op_p);
if (align != TYPE_ALIGN (type))
type = build_aligned_type (type, align);
alias_ptr_type = reference_alias_ptr_type (*use->op_p);
}
tree ref = create_mem_ref (&bsi, type, &aff, alias_ptr_type,
iv, base_hint, data->speed);
if (use->type == USE_PTR_ADDRESS)
{
ref = fold_build1 (ADDR_EXPR, build_pointer_type (use->mem_type), ref);
ref = fold_convert (get_use_type (use), ref);
ref = force_gimple_operand_gsi (&bsi, ref, true, NULL_TREE,
true, GSI_SAME_STMT);
}
else
copy_ref_info (ref, *use->op_p);
*use->op_p = ref;
}
/* Rewrites USE (the condition such that one of the arguments is an iv) using
candidate CAND. */
static void
rewrite_use_compare (struct ivopts_data *data,
struct iv_use *use, struct iv_cand *cand)
{
tree comp, op, bound;
gimple_stmt_iterator bsi = gsi_for_stmt (use->stmt);
enum tree_code compare;
struct iv_group *group = data->vgroups[use->group_id];
class cost_pair *cp = get_group_iv_cost (data, group, cand);
bound = cp->value;
if (bound)
{
tree var = var_at_stmt (data->current_loop, cand, use->stmt);
tree var_type = TREE_TYPE (var);
gimple_seq stmts;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Replacing exit test: ");
print_gimple_stmt (dump_file, use->stmt, 0, TDF_SLIM);
}
compare = cp->comp;
bound = unshare_expr (fold_convert (var_type, bound));
op = force_gimple_operand (bound, &stmts, true, NULL_TREE);
if (stmts)
gsi_insert_seq_on_edge_immediate (
loop_preheader_edge (data->current_loop),
stmts);
gcond *cond_stmt = as_a <gcond *> (use->stmt);
gimple_cond_set_lhs (cond_stmt, var);
gimple_cond_set_code (cond_stmt, compare);
gimple_cond_set_rhs (cond_stmt, op);
return;
}
/* The induction variable elimination failed; just express the original
giv. */
comp = get_computation_at (data->current_loop, use->stmt, use, cand);
gcc_assert (comp != NULL_TREE);
gcc_assert (use->op_p != NULL);
*use->op_p = force_gimple_operand_gsi (&bsi, comp, true,
SSA_NAME_VAR (*use->op_p),
true, GSI_SAME_STMT);
}
/* Rewrite the groups using the selected induction variables. */
static void
rewrite_groups (struct ivopts_data *data)
{
unsigned i, j;
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
struct iv_cand *cand = group->selected;
gcc_assert (cand);
if (group->type == USE_NONLINEAR_EXPR)
{
for (j = 0; j < group->vuses.length (); j++)
{
rewrite_use_nonlinear_expr (data, group->vuses[j], cand);
update_stmt (group->vuses[j]->stmt);
}
}
else if (address_p (group->type))
{
for (j = 0; j < group->vuses.length (); j++)
{
rewrite_use_address (data, group->vuses[j], cand);
update_stmt (group->vuses[j]->stmt);
}
}
else
{
gcc_assert (group->type == USE_COMPARE);
for (j = 0; j < group->vuses.length (); j++)
{
rewrite_use_compare (data, group->vuses[j], cand);
update_stmt (group->vuses[j]->stmt);
}
}
}
}
/* Removes the ivs that are not used after rewriting. */
static void
remove_unused_ivs (struct ivopts_data *data, bitmap toremove)
{
unsigned j;
bitmap_iterator bi;
/* Figure out an order in which to release SSA DEFs so that we don't
release something that we'd have to propagate into a debug stmt
afterwards. */
EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, j, bi)
{
struct version_info *info;
info = ver_info (data, j);
if (info->iv
&& !integer_zerop (info->iv->step)
&& !info->inv_id
&& !info->iv->nonlin_use
&& !info->preserve_biv)
{
bitmap_set_bit (toremove, SSA_NAME_VERSION (info->iv->ssa_name));
tree def = info->iv->ssa_name;
if (MAY_HAVE_DEBUG_BIND_STMTS && SSA_NAME_DEF_STMT (def))
{
imm_use_iterator imm_iter;
use_operand_p use_p;
gimple *stmt;
int count = 0;
FOR_EACH_IMM_USE_STMT (stmt, imm_iter, def)
{
if (!gimple_debug_bind_p (stmt))
continue;
/* We just want to determine whether to do nothing
(count == 0), to substitute the computed
expression into a single use of the SSA DEF by
itself (count == 1), or to use a debug temp
because the SSA DEF is used multiple times or as
part of a larger expression (count > 1). */
count++;
if (gimple_debug_bind_get_value (stmt) != def)
count++;
if (count > 1)
break;
}
if (!count)
continue;
struct iv_use dummy_use;
struct iv_cand *best_cand = NULL, *cand;
unsigned i, best_pref = 0, cand_pref;
tree comp = NULL_TREE;
memset (&dummy_use, 0, sizeof (dummy_use));
dummy_use.iv = info->iv;
for (i = 0; i < data->vgroups.length () && i < 64; i++)
{
cand = data->vgroups[i]->selected;
if (cand == best_cand)
continue;
cand_pref = operand_equal_p (cand->iv->step,
info->iv->step, 0)
? 4 : 0;
cand_pref
+= TYPE_MODE (TREE_TYPE (cand->iv->base))
== TYPE_MODE (TREE_TYPE (info->iv->base))
? 2 : 0;
cand_pref
+= TREE_CODE (cand->iv->base) == INTEGER_CST
? 1 : 0;
if (best_cand == NULL || best_pref < cand_pref)
{
tree this_comp
= get_debug_computation_at (data->current_loop,
SSA_NAME_DEF_STMT (def),
&dummy_use, cand);
if (this_comp)
{
best_cand = cand;
best_pref = cand_pref;
comp = this_comp;
}
}
}
if (!best_cand)
continue;
comp = unshare_expr (comp);
if (count > 1)
{
tree vexpr = build_debug_expr_decl (TREE_TYPE (comp));
/* FIXME: Is setting the mode really necessary? */
if (SSA_NAME_VAR (def))
SET_DECL_MODE (vexpr, DECL_MODE (SSA_NAME_VAR (def)));
else
SET_DECL_MODE (vexpr, TYPE_MODE (TREE_TYPE (vexpr)));
gdebug *def_temp
= gimple_build_debug_bind (vexpr, comp, NULL);
gimple_stmt_iterator gsi;
if (gimple_code (SSA_NAME_DEF_STMT (def)) == GIMPLE_PHI)
gsi = gsi_after_labels (gimple_bb
(SSA_NAME_DEF_STMT (def)));
else
gsi = gsi_for_stmt (SSA_NAME_DEF_STMT (def));
gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT);
comp = vexpr;
}
FOR_EACH_IMM_USE_STMT (stmt, imm_iter, def)
{
if (!gimple_debug_bind_p (stmt))
continue;
FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
SET_USE (use_p, comp);
update_stmt (stmt);
}
}
}
}
}
/* Frees memory occupied by class tree_niter_desc in *VALUE. Callback
for hash_map::traverse. */
bool
free_tree_niter_desc (edge const &, tree_niter_desc *const &value, void *)
{
free (value);
return true;
}
/* Frees data allocated by the optimization of a single loop. */
static void
free_loop_data (struct ivopts_data *data)
{
unsigned i, j;
bitmap_iterator bi;
tree obj;
if (data->niters)
{
data->niters->traverse<void *, free_tree_niter_desc> (NULL);
delete data->niters;
data->niters = NULL;
}
EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi)
{
struct version_info *info;
info = ver_info (data, i);
info->iv = NULL;
info->has_nonlin_use = false;
info->preserve_biv = false;
info->inv_id = 0;
}
bitmap_clear (data->relevant);
bitmap_clear (data->important_candidates);
for (i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
for (j = 0; j < group->vuses.length (); j++)
free (group->vuses[j]);
group->vuses.release ();
BITMAP_FREE (group->related_cands);
for (j = 0; j < group->n_map_members; j++)
{
if (group->cost_map[j].inv_vars)
BITMAP_FREE (group->cost_map[j].inv_vars);
if (group->cost_map[j].inv_exprs)
BITMAP_FREE (group->cost_map[j].inv_exprs);
}
free (group->cost_map);
free (group);
}
data->vgroups.truncate (0);
for (i = 0; i < data->vcands.length (); i++)
{
struct iv_cand *cand = data->vcands[i];
if (cand->inv_vars)
BITMAP_FREE (cand->inv_vars);
if (cand->inv_exprs)
BITMAP_FREE (cand->inv_exprs);
free (cand);
}
data->vcands.truncate (0);
if (data->version_info_size < num_ssa_names)
{
data->version_info_size = 2 * num_ssa_names;
free (data->version_info);
data->version_info = XCNEWVEC (struct version_info, data->version_info_size);
}
data->max_inv_var_id = 0;
data->max_inv_expr_id = 0;
FOR_EACH_VEC_ELT (decl_rtl_to_reset, i, obj)
SET_DECL_RTL (obj, NULL_RTX);
decl_rtl_to_reset.truncate (0);
data->inv_expr_tab->empty ();
data->iv_common_cand_tab->empty ();
data->iv_common_cands.truncate (0);
}
/* Finalizes data structures used by the iv optimization pass. LOOPS is the
loop tree. */
static void
tree_ssa_iv_optimize_finalize (struct ivopts_data *data)
{
free_loop_data (data);
free (data->version_info);
BITMAP_FREE (data->relevant);
BITMAP_FREE (data->important_candidates);
decl_rtl_to_reset.release ();
data->vgroups.release ();
data->vcands.release ();
delete data->inv_expr_tab;
data->inv_expr_tab = NULL;
free_affine_expand_cache (&data->name_expansion_cache);
if (data->base_object_map)
delete data->base_object_map;
delete data->iv_common_cand_tab;
data->iv_common_cand_tab = NULL;
data->iv_common_cands.release ();
obstack_free (&data->iv_obstack, NULL);
}
/* Returns true if the loop body BODY includes any function calls. */
static bool
loop_body_includes_call (basic_block *body, unsigned num_nodes)
{
gimple_stmt_iterator gsi;
unsigned i;
for (i = 0; i < num_nodes; i++)
for (gsi = gsi_start_bb (body[i]); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple *stmt = gsi_stmt (gsi);
if (is_gimple_call (stmt)
&& !gimple_call_internal_p (stmt)
&& !is_inexpensive_builtin (gimple_call_fndecl (stmt)))
return true;
}
return false;
}
/* Determine cost scaling factor for basic blocks in loop. */
#define COST_SCALING_FACTOR_BOUND (20)
static void
determine_scaling_factor (struct ivopts_data *data, basic_block *body)
{
int lfreq = data->current_loop->header->count.to_frequency (cfun);
if (!data->speed || lfreq <= 0)
return;
int max_freq = lfreq;
for (unsigned i = 0; i < data->current_loop->num_nodes; i++)
{
body[i]->aux = (void *)(intptr_t) 1;
if (max_freq < body[i]->count.to_frequency (cfun))
max_freq = body[i]->count.to_frequency (cfun);
}
if (max_freq > lfreq)
{
int divisor, factor;
/* Check if scaling factor itself needs to be scaled by the bound. This
is to avoid overflow when scaling cost according to profile info. */
if (max_freq / lfreq > COST_SCALING_FACTOR_BOUND)
{
divisor = max_freq;
factor = COST_SCALING_FACTOR_BOUND;
}
else
{
divisor = lfreq;
factor = 1;
}
for (unsigned i = 0; i < data->current_loop->num_nodes; i++)
{
int bfreq = body[i]->count.to_frequency (cfun);
if (bfreq <= lfreq)
continue;
body[i]->aux = (void*)(intptr_t) (factor * bfreq / divisor);
}
}
}
/* Find doloop comparison use and set its doloop_p on if found. */
static bool
find_doloop_use (struct ivopts_data *data)
{
struct loop *loop = data->current_loop;
for (unsigned i = 0; i < data->vgroups.length (); i++)
{
struct iv_group *group = data->vgroups[i];
if (group->type == USE_COMPARE)
{
gcc_assert (group->vuses.length () == 1);
struct iv_use *use = group->vuses[0];
gimple *stmt = use->stmt;
if (gimple_code (stmt) == GIMPLE_COND)
{
basic_block bb = gimple_bb (stmt);
edge true_edge, false_edge;
extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
/* This comparison is used for loop latch. Require latch is empty
for now. */
if ((loop->latch == true_edge->dest
|| loop->latch == false_edge->dest)
&& empty_block_p (loop->latch))
{
group->doloop_p = true;
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Doloop cmp iv use: ");
print_gimple_stmt (dump_file, stmt, TDF_DETAILS);
}
return true;
}
}
}
}
return false;
}
/* For the targets which support doloop, to predict whether later RTL doloop
transformation will perform on this loop, further detect the doloop use and
mark the flag doloop_use_p if predicted. */
void
analyze_and_mark_doloop_use (struct ivopts_data *data)
{
data->doloop_use_p = false;
if (!flag_branch_on_count_reg)
return;
if (data->current_loop->unroll == USHRT_MAX)
return;
if (!generic_predict_doloop_p (data))
return;
if (find_doloop_use (data))
{
data->doloop_use_p = true;
if (dump_file && (dump_flags & TDF_DETAILS))
{
struct loop *loop = data->current_loop;
fprintf (dump_file,
"Predict loop %d can perform"
" doloop optimization later.\n",
loop->num);
flow_loop_dump (loop, dump_file, NULL, 1);
}
}
}
/* Optimizes the LOOP. Returns true if anything changed. */
static bool
tree_ssa_iv_optimize_loop (struct ivopts_data *data, class loop *loop,
bitmap toremove)
{
bool changed = false;
class iv_ca *iv_ca;
edge exit = single_dom_exit (loop);
basic_block *body;
gcc_assert (!data->niters);
data->current_loop = loop;
data->loop_loc = find_loop_location (loop).get_location_t ();
data->speed = optimize_loop_for_speed_p (loop);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "Processing loop %d", loop->num);
if (data->loop_loc != UNKNOWN_LOCATION)
fprintf (dump_file, " at %s:%d", LOCATION_FILE (data->loop_loc),
LOCATION_LINE (data->loop_loc));
fprintf (dump_file, "\n");
if (exit)
{
fprintf (dump_file, " single exit %d -> %d, exit condition ",
exit->src->index, exit->dest->index);
print_gimple_stmt (dump_file, last_stmt (exit->src), 0, TDF_SLIM);
fprintf (dump_file, "\n");
}
fprintf (dump_file, "\n");
}
body = get_loop_body (loop);
data->body_includes_call = loop_body_includes_call (body, loop->num_nodes);
renumber_gimple_stmt_uids_in_blocks (body, loop->num_nodes);
data->loop_single_exit_p
= exit != NULL && loop_only_exit_p (loop, body, exit);
/* For each ssa name determines whether it behaves as an induction variable
in some loop. */
if (!find_induction_variables (data, body))
goto finish;
/* Finds interesting uses (item 1). */
find_interesting_uses (data, body);
if (data->vgroups.length () > MAX_CONSIDERED_GROUPS)
goto finish;
/* Determine cost scaling factor for basic blocks in loop. */
determine_scaling_factor (data, body);
/* Analyze doloop possibility and mark the doloop use if predicted. */
analyze_and_mark_doloop_use (data);
/* Finds candidates for the induction variables (item 2). */
find_iv_candidates (data);
/* Calculates the costs (item 3, part 1). */
determine_iv_costs (data);
determine_group_iv_costs (data);
determine_set_costs (data);
/* Find the optimal set of induction variables (item 3, part 2). */
iv_ca = find_optimal_iv_set (data);
/* Cleanup basic block aux field. */
for (unsigned i = 0; i < data->current_loop->num_nodes; i++)
body[i]->aux = NULL;
if (!iv_ca)
goto finish;
changed = true;
/* Create the new induction variables (item 4, part 1). */
create_new_ivs (data, iv_ca);
iv_ca_free (&iv_ca);
/* Rewrite the uses (item 4, part 2). */
rewrite_groups (data);
/* Remove the ivs that are unused after rewriting. */
remove_unused_ivs (data, toremove);
finish:
free (body);
free_loop_data (data);
return changed;
}
/* Main entry point. Optimizes induction variables in loops. */
void
tree_ssa_iv_optimize (void)
{
struct ivopts_data data;
auto_bitmap toremove;
tree_ssa_iv_optimize_init (&data);
mark_ssa_maybe_undefs ();
/* Optimize the loops starting with the innermost ones. */
for (auto loop : loops_list (cfun, LI_FROM_INNERMOST))
{
if (!dbg_cnt (ivopts_loop))
continue;
if (dump_file && (dump_flags & TDF_DETAILS))
flow_loop_dump (loop, dump_file, NULL, 1);
tree_ssa_iv_optimize_loop (&data, loop, toremove);
}
/* Remove eliminated IV defs. */
release_defs_bitset (toremove);
/* We have changed the structure of induction variables; it might happen
that definitions in the scev database refer to some of them that were
eliminated. */
scev_reset_htab ();
/* Likewise niter and control-IV information. */
free_numbers_of_iterations_estimates (cfun);
tree_ssa_iv_optimize_finalize (&data);
}
#include "gt-tree-ssa-loop-ivopts.h"
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