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/* Shared code for before and after reload gcse implementations.
Copyright (C) 1997-2024 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/>.
It is expected that more hunks of gcse.cc and postreload-gcse.cc should
migrate into this file. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "rtl.h"
#include "df.h"
#include "gcse-common.h"
/* Record all of the canonicalized MEMs of record_last_mem_set_info's insn.
Note we store a pair of elements in the list, so they have to be
taken off pairwise. */
void
canon_list_insert (rtx dest, const_rtx x ATTRIBUTE_UNUSED, void *data)
{
rtx dest_addr;
int bb;
modify_pair pair;
while (GET_CODE (dest) == SUBREG
|| GET_CODE (dest) == ZERO_EXTRACT
|| GET_CODE (dest) == STRICT_LOW_PART)
dest = XEXP (dest, 0);
/* If DEST is not a MEM, then it will not conflict with a load. Note
that function calls are assumed to clobber memory, but are handled
elsewhere. */
if (! MEM_P (dest))
return;
dest_addr = get_addr (XEXP (dest, 0));
dest_addr = canon_rtx (dest_addr);
rtx_insn *insn = ((struct gcse_note_stores_info *)data)->insn;
bb = BLOCK_FOR_INSN (insn)->index;
pair.dest = dest;
pair.dest_addr = dest_addr;
vec<modify_pair> *canon_mem_list
= ((struct gcse_note_stores_info *)data)->canon_mem_list;
canon_mem_list[bb].safe_push (pair);
}
/* Record memory modification information for INSN. We do not actually care
about the memory location(s) that are set, or even how they are set (consider
a CALL_INSN). We merely need to record which insns modify memory. */
void
record_last_mem_set_info_common (rtx_insn *insn,
vec<rtx_insn *> *modify_mem_list,
vec<modify_pair> *canon_modify_mem_list,
bitmap modify_mem_list_set,
bitmap blocks_with_calls)
{
int bb;
bb = BLOCK_FOR_INSN (insn)->index;
modify_mem_list[bb].safe_push (insn);
bitmap_set_bit (modify_mem_list_set, bb);
if (CALL_P (insn))
bitmap_set_bit (blocks_with_calls, bb);
else
{
struct gcse_note_stores_info data;
data.insn = insn;
data.canon_mem_list = canon_modify_mem_list;
note_stores (insn, canon_list_insert, (void*) &data);
}
}
/* For each block, compute whether X is transparent. X is either an
expression or an assignment [though we don't care which, for this context
an assignment is treated as an expression]. For each block where an
element of X is modified, reset the INDX bit in BMAP.
BLOCKS_WITH_CALLS indicates which blocks contain CALL_INSNs which kill
memory.
MODIFY_MEM_LIST_SET indicates which blocks have memory stores which might
kill a particular memory location.
CANON_MODIFY_MEM_LIST is the canonicalized list of memory locations modified
for each block. */
void
compute_transp (const_rtx x, int indx, sbitmap *bmap,
bitmap blocks_with_calls,
bitmap modify_mem_list_set,
vec<modify_pair> *canon_modify_mem_list)
{
int i, j;
enum rtx_code code;
const char *fmt;
/* repeat is used to turn tail-recursion into iteration since GCC
can't do it when there's no return value. */
repeat:
if (x == 0)
return;
code = GET_CODE (x);
switch (code)
{
case REG:
{
df_ref def;
for (def = DF_REG_DEF_CHAIN (REGNO (x));
def;
def = DF_REF_NEXT_REG (def))
bitmap_clear_bit (bmap[DF_REF_BB (def)->index], indx);
}
return;
case MEM:
if (! MEM_READONLY_P (x))
{
bitmap_iterator bi;
unsigned bb_index;
rtx x_addr;
x_addr = get_addr (XEXP (x, 0));
x_addr = canon_rtx (x_addr);
/* First handle all the blocks with calls. We don't need to
do any list walking for them. */
EXECUTE_IF_SET_IN_BITMAP (blocks_with_calls, 0, bb_index, bi)
{
bitmap_clear_bit (bmap[bb_index], indx);
}
/* Now iterate over the blocks which have memory modifications
but which do not have any calls. */
EXECUTE_IF_AND_COMPL_IN_BITMAP (modify_mem_list_set,
blocks_with_calls,
0, bb_index, bi)
{
vec<modify_pair> list
= canon_modify_mem_list[bb_index];
modify_pair *pair;
unsigned ix;
FOR_EACH_VEC_ELT_REVERSE (list, ix, pair)
{
rtx dest = pair->dest;
rtx dest_addr = pair->dest_addr;
if (canon_true_dependence (dest, GET_MODE (dest),
dest_addr, x, x_addr))
{
bitmap_clear_bit (bmap[bb_index], indx);
break;
}
}
}
}
x = XEXP (x, 0);
goto repeat;
case PC:
case CONST:
CASE_CONST_ANY:
case SYMBOL_REF:
case LABEL_REF:
case ADDR_VEC:
case ADDR_DIFF_VEC:
return;
default:
break;
}
for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
{
if (fmt[i] == 'e')
{
/* If we are about to do the last recursive call
needed at this level, change it into iteration.
This function is called enough to be worth it. */
if (i == 0)
{
x = XEXP (x, i);
goto repeat;
}
compute_transp (XEXP (x, i), indx, bmap, blocks_with_calls,
modify_mem_list_set, canon_modify_mem_list);
}
else if (fmt[i] == 'E')
for (j = 0; j < XVECLEN (x, i); j++)
compute_transp (XVECEXP (x, i, j), indx, bmap, blocks_with_calls,
modify_mem_list_set, canon_modify_mem_list);
}
}
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