gcc/ifcvt.h

   1 /* If-conversion header file.
   2    Copyright (C) 2014-2025 Free Software Foundation, Inc.
   3
   4    This file is part of GCC.
   5
   6    GCC is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    GCC is distributed in the hope that it will be useful, but WITHOUT
  12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  14    License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GCC; see the file COPYING3.  If not see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_IFCVT_H
  21 #define GCC_IFCVT_H
  22
  23 /* Structure to group all of the information to process IF-THEN and
  24    IF-THEN-ELSE blocks for the conditional execution support.  */
  25
  26 struct ce_if_block
  27 {
  28   basic_block test_bb;                  /* First test block.  */
  29   basic_block then_bb;                  /* THEN block.  */
  30   basic_block else_bb;                  /* ELSE block or NULL.  */
  31   basic_block join_bb;                  /* Join THEN/ELSE blocks.  */
  32   basic_block last_test_bb;             /* Last bb to hold && or || tests.  */
  33   int num_multiple_test_blocks;         /* # of && and || basic blocks.  */
  34   int num_and_and_blocks;               /* # of && blocks.  */
  35   int num_or_or_blocks;                 /* # of || blocks.  */
  36   int num_multiple_test_insns;          /* # of insns in && and || blocks.  */
  37   int and_and_p;                        /* Complex test is &&.  */
  38   int num_then_insns;                   /* # of insns in THEN block.  */
  39   int num_else_insns;                   /* # of insns in ELSE block.  */
  40   int pass;                             /* Pass number.  */
  41 };
  42
  43 struct noce_multiple_sets_info
  44 {
  45   /* A list of indices to instructions that we need to rewire into this
  46      instruction when we replace them with temporary conditional moves.  */
  47   auto_vec<int> rewired_src;
  48   /* The true targets for a conditional move.  */
  49   rtx target;
  50   /* The temporaries introduced to allow us to not consider register
  51      overlap.  */
  52   rtx temporary;
  53   /* The insns we've emitted.  */
  54   rtx_insn *unmodified_insn;
  55   /* True if a simple move can be used instead of a conditional move.  */
  56   bool need_cmov;
  57 };
  58
  59 /* Used by noce_process_if_block to communicate with its subroutines.
  60
  61    The subroutines know that A and B may be evaluated freely.  They
  62    know that X is a register.  They should insert new instructions
  63    before cond_earliest.  */
  64
  65 struct noce_if_info
  66 {
  67   /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block.  */
  68   basic_block test_bb, then_bb, else_bb, join_bb;
  69
  70   /* The jump that ends TEST_BB.  */
  71   rtx_insn *jump;
  72
  73   /* The jump condition.  */
  74   rtx cond;
  75
  76   /* Reversed jump condition.  */
  77   rtx rev_cond;
  78
  79   /* New insns should be inserted before this one.  */
  80   rtx_insn *cond_earliest;
  81
  82   /* Insns in the THEN and ELSE block.  There is always just this
  83      one insns in those blocks.  The insns are single_set insns.
  84      If there was no ELSE block, INSN_B is the last insn before
  85      COND_EARLIEST, or NULL_RTX.  In the former case, the insn
  86      operands are still valid, as if INSN_B was moved down below
  87      the jump.  */
  88   rtx_insn *insn_a, *insn_b;
  89
  90   /* The SET_SRC of INSN_A and INSN_B.  */
  91   rtx a, b;
  92
  93   /* The SET_DEST of INSN_A.  */
  94   rtx x;
  95
  96   /* The original set destination that the THEN and ELSE basic blocks finally
  97      write their result to.  */
  98   rtx orig_x;
  99   /* True if this if block is not canonical.  In the canonical form of
 100      if blocks, the THEN_BB is the block reached via the fallthru edge
 101      from TEST_BB.  For the noce transformations, we allow the symmetric
 102      form as well.  */
 103   bool then_else_reversed;
 104
 105   /* True if THEN_BB is conditional on !COND rather than COND.
 106      This is used if:
 107
 108      - JUMP branches to THEN_BB on COND
 109      - JUMP falls through to JOIN_BB on !COND
 110      - COND cannot be reversed.  */
 111   bool cond_inverted;
 112
 113   /* True if the contents of then_bb and else_bb are a
 114      simple single set instruction.  */
 115   bool then_simple;
 116   bool else_simple;
 117
 118   /* True if we're optimisizing the control block for speed, false if
 119      we're optimizing for size.  */
 120   bool speed_p;
 121
 122   /* An estimate of the original costs.  When optimizing for size, this is the
 123      combined cost of COND, JUMP and the costs for THEN_BB and ELSE_BB.
 124      When optimizing for speed, we use the costs of COND plus weighted average
 125      of the costs for THEN_BB and ELSE_BB, as computed in the next field.  */
 126   unsigned int original_cost;
 127
 128   /* Maximum permissible cost for the unconditional sequence we should
 129      generate to replace this branch.  */
 130   unsigned int max_seq_cost;
 131
 132   /* The name of the noce transform that succeeded in if-converting
 133      this structure.  Used for debugging.  */
 134   const char *transform_name;
 135 };
 136
 137 #endif /* GCC_IFCVT_H */