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rtl-optimization: [PR102733] DSE removing address which only differ by address space.

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The problem here is DSE was not taking into account the address space
which meant if you had two addresses say `fs:0` and `gs:0` (on x86_64),
DSE would think they were the same and remove the first store.
This fixes that issue by adding a check for the address space too.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

	PR rtl-optimization/102733

gcc/ChangeLog:

	* dse.cc (store_info): Add addrspace field.
	(record_store): Record the address space
	and check to make sure they are the same.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/addr-space-6.c: New test.
This commit is contained in:
Andrew Pinski 2023-06-01 21:17:56 -07:00
parent df0853d72d
commit 64ca6aa74b
2 changed files with 29 additions and 1 deletions
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9
gcc/dse.cc
View file

@ -251,6 +251,9 @@ public:
and known (rather than -1). */
poly_int64 width;
/* The address space that the memory reference uses. */
unsigned char addrspace;
union
{
/* A bitmask as wide as the number of bytes in the word that
@ -1524,6 +1527,7 @@ record_store (rtx body, bb_info_t bb_info)
ptr = active_local_stores;
last = NULL;
redundant_reason = NULL;
unsigned char addrspace = MEM_ADDR_SPACE (mem);
mem = canon_rtx (mem);
if (group_id < 0)
@ -1548,7 +1552,9 @@ record_store (rtx body, bb_info_t bb_info)
while (!s_info->is_set)
s_info = s_info->next;
if (s_info->group_id == group_id && s_info->cse_base == base)
if (s_info->group_id == group_id
&& s_info->cse_base == base
&& s_info->addrspace == addrspace)
{
HOST_WIDE_INT i;
if (dump_file && (dump_flags & TDF_DETAILS))
@ -1688,6 +1694,7 @@ record_store (rtx body, bb_info_t bb_info)
store_info->rhs = rhs;
store_info->const_rhs = const_rhs;
store_info->redundant_reason = redundant_reason;
store_info->addrspace = addrspace;
/* If this is a clobber, we return 0. We will only be able to
delete this insn if there is only one store USED store, but we

21
gcc/testsuite/gcc.target/i386/addr-space-6.c Normal file
View file

@ -0,0 +1,21 @@
/* PR rtl-optimization/102733 */
/* { dg-do compile } */
/* { dg-options "-O1" } */
/* DSE was removing a store to fs:0 (correctly)
and gs:0 (incorrectly) as DSE didn't take into
account the address space was different. */
void test_null_store (void)
{
int __seg_fs *fs = (int __seg_fs *)0;
*fs = 1;
int __seg_gs *gs = (int __seg_gs *)0;
*gs = 2;
*fs = 3;
}
/* { dg-final { scan-assembler-times "movl\t" 2 } } */
/* { dg-final { scan-assembler "gs:" } } */
/* { dg-final { scan-assembler "fs:" } } */