752 lines
22 KiB
C++
752 lines
22 KiB
C++
/* Control flow graph building code for GNU compiler.
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Copyright (C) 1987-2022 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "backend.h"
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#include "rtl.h"
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#include "cfghooks.h"
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#include "memmodel.h"
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#include "emit-rtl.h"
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#include "cfgrtl.h"
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#include "cfganal.h"
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#include "cfgbuild.h"
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#include "except.h"
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#include "stmt.h"
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static void make_edges (basic_block, basic_block, int);
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static void make_label_edge (sbitmap, basic_block, rtx, int);
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static void find_bb_boundaries (basic_block);
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static void compute_outgoing_frequencies (basic_block);
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/* Return true if insn is something that should be contained inside basic
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block. */
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bool
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inside_basic_block_p (const rtx_insn *insn)
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{
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switch (GET_CODE (insn))
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{
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case CODE_LABEL:
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/* Avoid creating of basic block for jumptables. */
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return (NEXT_INSN (insn) == 0
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|| ! JUMP_TABLE_DATA_P (NEXT_INSN (insn)));
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case JUMP_INSN:
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case CALL_INSN:
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case INSN:
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case DEBUG_INSN:
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return true;
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case JUMP_TABLE_DATA:
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case BARRIER:
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case NOTE:
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return false;
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default:
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gcc_unreachable ();
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}
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}
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/* Return true if INSN may cause control flow transfer, so it should be last in
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the basic block. */
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bool
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control_flow_insn_p (const rtx_insn *insn)
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{
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switch (GET_CODE (insn))
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{
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case NOTE:
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case CODE_LABEL:
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case DEBUG_INSN:
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return false;
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case JUMP_INSN:
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return true;
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case CALL_INSN:
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/* Noreturn and sibling call instructions terminate the basic blocks
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(but only if they happen unconditionally). */
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if ((SIBLING_CALL_P (insn)
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|| find_reg_note (insn, REG_NORETURN, 0))
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&& GET_CODE (PATTERN (insn)) != COND_EXEC)
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return true;
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/* Call insn may return to the nonlocal goto handler. */
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if (can_nonlocal_goto (insn))
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return true;
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break;
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case INSN:
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/* Treat trap instructions like noreturn calls (same provision). */
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if (GET_CODE (PATTERN (insn)) == TRAP_IF
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&& XEXP (PATTERN (insn), 0) == const1_rtx)
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return true;
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if (!cfun->can_throw_non_call_exceptions)
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return false;
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break;
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case JUMP_TABLE_DATA:
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case BARRIER:
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/* It is nonsense to reach this when looking for the
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end of basic block, but before dead code is eliminated
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this may happen. */
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return false;
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default:
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gcc_unreachable ();
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}
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return can_throw_internal (insn);
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}
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/* Create an edge between two basic blocks. FLAGS are auxiliary information
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about the edge that is accumulated between calls. */
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/* Create an edge from a basic block to a label. */
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static void
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make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags)
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{
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gcc_assert (LABEL_P (label));
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/* If the label was never emitted, this insn is junk, but avoid a
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crash trying to refer to BLOCK_FOR_INSN (label). This can happen
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as a result of a syntax error and a diagnostic has already been
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printed. */
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if (INSN_UID (label) == 0)
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return;
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cached_make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags);
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}
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/* Create the edges generated by INSN in REGION. */
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void
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rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx insn)
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{
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eh_landing_pad lp = get_eh_landing_pad_from_rtx (insn);
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if (lp)
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{
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rtx_insn *label = lp->landing_pad;
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/* During initial rtl generation, use the post_landing_pad. */
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if (label == NULL)
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{
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gcc_assert (lp->post_landing_pad);
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label = label_rtx (lp->post_landing_pad);
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}
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make_label_edge (edge_cache, src, label,
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EDGE_ABNORMAL | EDGE_EH
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| (CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0));
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}
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}
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/* States of basic block as seen by find_many_sub_basic_blocks. */
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enum state {
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/* Basic blocks created via split_block belong to this state.
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make_edges will examine these basic blocks to see if we need to
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create edges going out of them. */
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BLOCK_NEW = 0,
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/* Basic blocks that do not need examining belong to this state.
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These blocks will be left intact. In particular, make_edges will
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not create edges going out of these basic blocks. */
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BLOCK_ORIGINAL,
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/* Basic blocks that may need splitting (due to a label appearing in
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the middle, etc) belong to this state. After splitting them,
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make_edges will create edges going out of them as needed. */
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BLOCK_TO_SPLIT
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};
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#define STATE(BB) (enum state) ((size_t) (BB)->aux)
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#define SET_STATE(BB, STATE) ((BB)->aux = (void *) (size_t) (STATE))
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/* Used internally by purge_dead_tablejump_edges, ORed into state. */
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#define BLOCK_USED_BY_TABLEJUMP 32
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#define FULL_STATE(BB) ((size_t) (BB)->aux)
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/* Identify the edges going out of basic blocks between MIN and MAX,
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inclusive, that have their states set to BLOCK_NEW or
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BLOCK_TO_SPLIT.
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UPDATE_P should be nonzero if we are updating CFG and zero if we
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are building CFG from scratch. */
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static void
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make_edges (basic_block min, basic_block max, int update_p)
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{
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basic_block bb;
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sbitmap edge_cache = NULL;
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/* Heavy use of computed goto in machine-generated code can lead to
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nearly fully-connected CFGs. In that case we spend a significant
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amount of time searching the edge lists for duplicates. */
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if (!vec_safe_is_empty (forced_labels)
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|| cfun->cfg->max_jumptable_ents > 100)
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edge_cache = sbitmap_alloc (last_basic_block_for_fn (cfun));
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/* By nature of the way these get numbered, ENTRY_BLOCK_PTR->next_bb block
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is always the entry. */
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if (min == ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb)
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make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), min, EDGE_FALLTHRU);
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FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
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{
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rtx_insn *insn;
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enum rtx_code code;
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edge e;
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edge_iterator ei;
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if (STATE (bb) == BLOCK_ORIGINAL)
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continue;
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/* If we have an edge cache, cache edges going out of BB. */
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if (edge_cache)
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{
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bitmap_clear (edge_cache);
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if (update_p)
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{
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FOR_EACH_EDGE (e, ei, bb->succs)
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if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
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bitmap_set_bit (edge_cache, e->dest->index);
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}
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}
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if (LABEL_P (BB_HEAD (bb))
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&& LABEL_ALT_ENTRY_P (BB_HEAD (bb)))
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cached_make_edge (NULL, ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0);
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/* Examine the last instruction of the block, and discover the
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ways we can leave the block. */
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insn = BB_END (bb);
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code = GET_CODE (insn);
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/* A branch. */
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if (code == JUMP_INSN)
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{
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rtx tmp;
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rtx_jump_table_data *table;
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/* Recognize a non-local goto as a branch outside the
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current function. */
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if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
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;
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/* Recognize a tablejump and do the right thing. */
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else if (tablejump_p (insn, NULL, &table))
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{
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rtvec vec = table->get_labels ();
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int j;
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for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
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make_label_edge (edge_cache, bb,
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XEXP (RTVEC_ELT (vec, j), 0), 0);
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/* Some targets (eg, ARM) emit a conditional jump that also
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contains the out-of-range target. Scan for these and
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add an edge if necessary. */
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if ((tmp = single_set (insn)) != NULL
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&& SET_DEST (tmp) == pc_rtx
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&& GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
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&& GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
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make_label_edge (edge_cache, bb,
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label_ref_label (XEXP (SET_SRC (tmp), 2)), 0);
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}
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/* If this is a computed jump, then mark it as reaching
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everything on the forced_labels list. */
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else if (computed_jump_p (insn))
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{
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rtx_insn *insn;
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unsigned int i;
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FOR_EACH_VEC_SAFE_ELT (forced_labels, i, insn)
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make_label_edge (edge_cache, bb, insn, EDGE_ABNORMAL);
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}
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/* Returns create an exit out. */
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else if (returnjump_p (insn))
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cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun), 0);
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/* Recognize asm goto and do the right thing. */
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else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL)
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{
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int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp);
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for (i = 0; i < n; ++i)
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make_label_edge (edge_cache, bb,
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XEXP (ASM_OPERANDS_LABEL (tmp, i), 0), 0);
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}
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/* Otherwise, we have a plain conditional or unconditional jump. */
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else
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{
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gcc_assert (JUMP_LABEL (insn));
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make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0);
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}
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}
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/* If this is a sibling call insn, then this is in effect a combined call
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and return, and so we need an edge to the exit block. No need to
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worry about EH edges, since we wouldn't have created the sibling call
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in the first place. */
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if (code == CALL_INSN && SIBLING_CALL_P (insn))
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cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun),
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EDGE_SIBCALL | EDGE_ABNORMAL);
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/* If this is a CALL_INSN, then mark it as reaching the active EH
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handler for this CALL_INSN. If we're handling non-call
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exceptions then any insn can reach any of the active handlers.
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Also mark the CALL_INSN as reaching any nonlocal goto handler. */
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else if (code == CALL_INSN || cfun->can_throw_non_call_exceptions)
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{
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/* Add any appropriate EH edges. */
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rtl_make_eh_edge (edge_cache, bb, insn);
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if (code == CALL_INSN)
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{
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if (can_nonlocal_goto (insn))
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{
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/* ??? This could be made smarter: in some cases it's
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possible to tell that certain calls will not do a
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nonlocal goto. For example, if the nested functions
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that do the nonlocal gotos do not have their addresses
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taken, then only calls to those functions or to other
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nested functions that use them could possibly do
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nonlocal gotos. */
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for (rtx_insn_list *x = nonlocal_goto_handler_labels;
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x;
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x = x->next ())
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make_label_edge (edge_cache, bb, x->insn (),
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EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
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}
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if (flag_tm)
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{
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rtx note;
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for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
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if (REG_NOTE_KIND (note) == REG_TM)
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make_label_edge (edge_cache, bb, XEXP (note, 0),
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EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
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}
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}
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}
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/* Find out if we can drop through to the next block. */
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insn = NEXT_INSN (insn);
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e = find_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun));
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if (e && e->flags & EDGE_FALLTHRU)
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insn = NULL;
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while (insn
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&& NOTE_P (insn)
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&& NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK)
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insn = NEXT_INSN (insn);
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if (!insn)
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cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR_FOR_FN (cfun),
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EDGE_FALLTHRU);
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else if (bb->next_bb != EXIT_BLOCK_PTR_FOR_FN (cfun))
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{
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if (insn == BB_HEAD (bb->next_bb))
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cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU);
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}
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}
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if (edge_cache)
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sbitmap_free (edge_cache);
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}
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static void
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mark_tablejump_edge (rtx label)
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{
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basic_block bb;
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gcc_assert (LABEL_P (label));
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/* See comment in make_label_edge. */
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if (INSN_UID (label) == 0)
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return;
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bb = BLOCK_FOR_INSN (label);
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SET_STATE (bb, FULL_STATE (bb) | BLOCK_USED_BY_TABLEJUMP);
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}
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static void
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purge_dead_tablejump_edges (basic_block bb, rtx_jump_table_data *table)
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{
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rtx_insn *insn = BB_END (bb);
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rtx tmp;
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rtvec vec;
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int j;
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edge_iterator ei;
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edge e;
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vec = table->get_labels ();
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for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
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mark_tablejump_edge (XEXP (RTVEC_ELT (vec, j), 0));
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/* Some targets (eg, ARM) emit a conditional jump that also
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contains the out-of-range target. Scan for these and
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add an edge if necessary. */
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if ((tmp = single_set (insn)) != NULL
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&& SET_DEST (tmp) == pc_rtx
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&& GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
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&& GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
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mark_tablejump_edge (label_ref_label (XEXP (SET_SRC (tmp), 2)));
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for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
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{
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if (FULL_STATE (e->dest) & BLOCK_USED_BY_TABLEJUMP)
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SET_STATE (e->dest, FULL_STATE (e->dest)
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& ~(size_t) BLOCK_USED_BY_TABLEJUMP);
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else if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
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{
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remove_edge (e);
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continue;
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}
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ei_next (&ei);
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}
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}
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/* Scan basic block BB for possible BB boundaries inside the block
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and create new basic blocks in the progress. */
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static void
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find_bb_boundaries (basic_block bb)
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{
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basic_block orig_bb = bb;
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rtx_insn *insn = BB_HEAD (bb);
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rtx_insn *end = BB_END (bb), *x;
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rtx_jump_table_data *table;
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rtx_insn *flow_transfer_insn = NULL;
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rtx_insn *debug_insn = NULL;
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edge fallthru = NULL;
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bool skip_purge;
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if (insn == end)
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return;
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if (DEBUG_INSN_P (insn) || DEBUG_INSN_P (end))
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{
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/* Check whether, without debug insns, the insn==end test above
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would have caused us to return immediately, and behave the
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same way even with debug insns. If we don't do this, debug
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insns could cause us to purge dead edges at different times,
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which could in turn change the cfg and affect codegen
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decisions in subtle but undesirable ways. */
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while (insn != end && DEBUG_INSN_P (insn))
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insn = NEXT_INSN (insn);
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rtx_insn *e = end;
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while (insn != e && DEBUG_INSN_P (e))
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e = PREV_INSN (e);
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if (insn == e)
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{
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/* If there are debug insns after a single insn that is a
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control flow insn in the block, we'd have left right
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away, but we should clean up the debug insns after the
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control flow insn, because they can't remain in the same
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block. So, do the debug insn cleaning up, but then bail
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out without purging dead edges as we would if the debug
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insns hadn't been there. */
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if (e != end && !DEBUG_INSN_P (e) && control_flow_insn_p (e))
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{
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skip_purge = true;
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flow_transfer_insn = e;
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goto clean_up_debug_after_control_flow;
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}
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return;
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}
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}
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if (LABEL_P (insn))
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insn = NEXT_INSN (insn);
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/* Scan insn chain and try to find new basic block boundaries. */
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while (1)
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{
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enum rtx_code code = GET_CODE (insn);
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if (code == DEBUG_INSN)
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{
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if (flow_transfer_insn && !debug_insn)
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debug_insn = insn;
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}
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/* In case we've previously seen an insn that effects a control
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flow transfer, split the block. */
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else if ((flow_transfer_insn || code == CODE_LABEL)
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&& inside_basic_block_p (insn))
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{
|
||
rtx_insn *prev = PREV_INSN (insn);
|
||
|
||
/* If the first non-debug inside_basic_block_p insn after a control
|
||
flow transfer is not a label, split the block before the debug
|
||
insn instead of before the non-debug insn, so that the debug
|
||
insns are not lost. */
|
||
if (debug_insn && code != CODE_LABEL && code != BARRIER)
|
||
prev = PREV_INSN (debug_insn);
|
||
fallthru = split_block (bb, prev);
|
||
if (flow_transfer_insn)
|
||
{
|
||
BB_END (bb) = flow_transfer_insn;
|
||
|
||
rtx_insn *next;
|
||
/* Clean up the bb field for the insns between the blocks. */
|
||
for (x = NEXT_INSN (flow_transfer_insn);
|
||
x != BB_HEAD (fallthru->dest);
|
||
x = next)
|
||
{
|
||
next = NEXT_INSN (x);
|
||
/* Debug insns should not be in between basic blocks,
|
||
drop them on the floor. */
|
||
if (DEBUG_INSN_P (x))
|
||
delete_insn (x);
|
||
else if (!BARRIER_P (x))
|
||
set_block_for_insn (x, NULL);
|
||
}
|
||
}
|
||
|
||
bb = fallthru->dest;
|
||
remove_edge (fallthru);
|
||
/* BB is unreachable at this point - we need to determine its profile
|
||
once edges are built. */
|
||
bb->count = profile_count::uninitialized ();
|
||
flow_transfer_insn = NULL;
|
||
debug_insn = NULL;
|
||
if (code == CODE_LABEL && LABEL_ALT_ENTRY_P (insn))
|
||
make_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), bb, 0);
|
||
}
|
||
else if (code == BARRIER)
|
||
{
|
||
/* __builtin_unreachable () may cause a barrier to be emitted in
|
||
the middle of a BB. We need to split it in the same manner as
|
||
if the barrier were preceded by a control_flow_insn_p insn. */
|
||
if (!flow_transfer_insn)
|
||
flow_transfer_insn = prev_nonnote_nondebug_insn_bb (insn);
|
||
debug_insn = NULL;
|
||
}
|
||
|
||
if (control_flow_insn_p (insn))
|
||
flow_transfer_insn = insn;
|
||
if (insn == end)
|
||
break;
|
||
insn = NEXT_INSN (insn);
|
||
}
|
||
|
||
/* In case expander replaced normal insn by sequence terminating by
|
||
return and barrier, or possibly other sequence not behaving like
|
||
ordinary jump, we need to take care and move basic block boundary. */
|
||
if (flow_transfer_insn && flow_transfer_insn != end)
|
||
{
|
||
skip_purge = false;
|
||
|
||
clean_up_debug_after_control_flow:
|
||
BB_END (bb) = flow_transfer_insn;
|
||
|
||
/* Clean up the bb field for the insns that do not belong to BB. */
|
||
rtx_insn *next;
|
||
for (x = NEXT_INSN (flow_transfer_insn); ; x = next)
|
||
{
|
||
next = NEXT_INSN (x);
|
||
/* Debug insns should not be in between basic blocks,
|
||
drop them on the floor. */
|
||
if (DEBUG_INSN_P (x))
|
||
delete_insn (x);
|
||
else if (!BARRIER_P (x))
|
||
set_block_for_insn (x, NULL);
|
||
if (x == end)
|
||
break;
|
||
}
|
||
|
||
if (skip_purge)
|
||
return;
|
||
}
|
||
|
||
/* We've possibly replaced the conditional jump by conditional jump
|
||
followed by cleanup at fallthru edge, so the outgoing edges may
|
||
be dead. */
|
||
purge_dead_edges (bb);
|
||
|
||
/* purge_dead_edges doesn't handle tablejump's, but if we have split the
|
||
basic block, we might need to kill some edges. */
|
||
if (bb != orig_bb && tablejump_p (BB_END (bb), NULL, &table))
|
||
purge_dead_tablejump_edges (bb, table);
|
||
}
|
||
|
||
/* Assume that frequency of basic block B is known. Compute frequencies
|
||
and probabilities of outgoing edges. */
|
||
|
||
static void
|
||
compute_outgoing_frequencies (basic_block b)
|
||
{
|
||
edge e, f;
|
||
edge_iterator ei;
|
||
|
||
if (EDGE_COUNT (b->succs) == 2)
|
||
{
|
||
rtx note = find_reg_note (BB_END (b), REG_BR_PROB, NULL);
|
||
int probability;
|
||
|
||
if (note)
|
||
{
|
||
probability = XINT (note, 0);
|
||
e = BRANCH_EDGE (b);
|
||
e->probability
|
||
= profile_probability::from_reg_br_prob_note (probability);
|
||
f = FALLTHRU_EDGE (b);
|
||
f->probability = e->probability.invert ();
|
||
return;
|
||
}
|
||
else
|
||
{
|
||
guess_outgoing_edge_probabilities (b);
|
||
}
|
||
}
|
||
else if (single_succ_p (b))
|
||
{
|
||
e = single_succ_edge (b);
|
||
e->probability = profile_probability::always ();
|
||
return;
|
||
}
|
||
else
|
||
{
|
||
/* We rely on BBs with more than two successors to have sane probabilities
|
||
and do not guess them here. For BBs terminated by switch statements
|
||
expanded to jump-table jump, we have done the right thing during
|
||
expansion. For EH edges, we still guess the probabilities here. */
|
||
bool complex_edge = false;
|
||
FOR_EACH_EDGE (e, ei, b->succs)
|
||
if (e->flags & EDGE_COMPLEX)
|
||
{
|
||
complex_edge = true;
|
||
break;
|
||
}
|
||
if (complex_edge)
|
||
guess_outgoing_edge_probabilities (b);
|
||
}
|
||
}
|
||
|
||
/* Assume that some pass has inserted labels or control flow
|
||
instructions within a basic block. Split basic blocks as needed
|
||
and create edges. */
|
||
|
||
void
|
||
find_many_sub_basic_blocks (sbitmap blocks)
|
||
{
|
||
basic_block bb, min, max;
|
||
bool found = false;
|
||
auto_vec<unsigned int> n_succs;
|
||
n_succs.safe_grow_cleared (last_basic_block_for_fn (cfun), true);
|
||
|
||
FOR_EACH_BB_FN (bb, cfun)
|
||
SET_STATE (bb,
|
||
bitmap_bit_p (blocks, bb->index) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL);
|
||
|
||
FOR_EACH_BB_FN (bb, cfun)
|
||
if (STATE (bb) == BLOCK_TO_SPLIT)
|
||
{
|
||
int n = last_basic_block_for_fn (cfun);
|
||
unsigned int ns = EDGE_COUNT (bb->succs);
|
||
|
||
find_bb_boundaries (bb);
|
||
if (n == last_basic_block_for_fn (cfun) && ns == EDGE_COUNT (bb->succs))
|
||
n_succs[bb->index] = EDGE_COUNT (bb->succs);
|
||
}
|
||
|
||
FOR_EACH_BB_FN (bb, cfun)
|
||
if (STATE (bb) != BLOCK_ORIGINAL)
|
||
{
|
||
found = true;
|
||
break;
|
||
}
|
||
|
||
if (!found)
|
||
return;
|
||
|
||
min = max = bb;
|
||
for (; bb != EXIT_BLOCK_PTR_FOR_FN (cfun); bb = bb->next_bb)
|
||
if (STATE (bb) != BLOCK_ORIGINAL)
|
||
max = bb;
|
||
|
||
/* Now re-scan and wire in all edges. This expect simple (conditional)
|
||
jumps at the end of each new basic blocks. */
|
||
make_edges (min, max, 1);
|
||
|
||
/* Update branch probabilities. Expect only (un)conditional jumps
|
||
to be created with only the forward edges. */
|
||
if (profile_status_for_fn (cfun) != PROFILE_ABSENT)
|
||
FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb)
|
||
{
|
||
edge e;
|
||
edge_iterator ei;
|
||
|
||
if (STATE (bb) == BLOCK_ORIGINAL)
|
||
continue;
|
||
if (STATE (bb) == BLOCK_NEW)
|
||
{
|
||
bool initialized_src = false, uninitialized_src = false;
|
||
bb->count = profile_count::zero ();
|
||
FOR_EACH_EDGE (e, ei, bb->preds)
|
||
{
|
||
if (e->count ().initialized_p ())
|
||
{
|
||
bb->count += e->count ();
|
||
initialized_src = true;
|
||
}
|
||
else
|
||
uninitialized_src = true;
|
||
}
|
||
/* When some edges are missing with read profile, this is
|
||
most likely because RTL expansion introduced loop.
|
||
When profile is guessed we may have BB that is reachable
|
||
from unlikely path as well as from normal path.
|
||
|
||
TODO: We should handle loops created during BB expansion
|
||
correctly here. For now we assume all those loop to cycle
|
||
precisely once. */
|
||
if (!initialized_src
|
||
|| (uninitialized_src
|
||
&& profile_status_for_fn (cfun) < PROFILE_GUESSED))
|
||
bb->count = profile_count::uninitialized ();
|
||
}
|
||
/* If nothing changed, there is no need to create new BBs. */
|
||
else if (EDGE_COUNT (bb->succs) == n_succs[bb->index])
|
||
{
|
||
/* In rare occassions RTL expansion might have mistakely assigned
|
||
a probabilities different from what is in CFG. This happens
|
||
when we try to split branch to two but optimize out the
|
||
second branch during the way. See PR81030. */
|
||
if (JUMP_P (BB_END (bb)) && any_condjump_p (BB_END (bb))
|
||
&& EDGE_COUNT (bb->succs) >= 2)
|
||
update_br_prob_note (bb);
|
||
continue;
|
||
}
|
||
|
||
compute_outgoing_frequencies (bb);
|
||
}
|
||
|
||
FOR_EACH_BB_FN (bb, cfun)
|
||
SET_STATE (bb, 0);
|
||
}
|