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* [Bug target/114605] New: [14 Regression] wrong code with -march=z13 -O0 since r14-5831
@ 2024-04-05 13:23 jakub at gcc dot gnu.org
2024-04-05 13:23 ` [Bug target/114605] " jakub at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2024-04-05 13:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114605
Bug ID: 114605
Summary: [14 Regression] wrong code with -march=z13 -O0 since
r14-5831
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
Since r14-5831-gaae723d360ca26cd9fd0b039fb0a616bd0eae363 we miscompile the
following testcase on s390x-linux with -O0 -march=z13:
typedef struct { const float *a; int b, c; float *d; } S;
__attribute__((noipa)) void
bar (void)
{
}
__attribute__((noinline, optimize (2))) static void
foo (S *e)
{
const float *f;
float *g;
float h[4] = { 0.0, 0.0, 1.0, 1.0 };
if (!e->b)
f = h;
else
f = e->a;
g = &e->d[0];
__builtin_memcpy (g, f, sizeof (float) * 4);
bar ();
if (!e->b)
if (g[0] != 0.0 || g[1] != 0.0 || g[2] != 1.0 || g[3] != 1.0)
__builtin_abort ();
}
int
main ()
{
float d[4];
S e = { .d = d };
foo (&e);
return 0;
}
The optimized dump difference from the previous commit is
@@ -23,7 +23,6 @@ Removing basic block 17
__attribute__((optimize (2), noinline))
void foo (struct S * e)
{
- float h[4];
float * g;
const float * f;
int _1;
@@ -32,10 +31,10 @@ void foo (struct S * e)
float _4;
float _5;
float _6;
- uint128_t _13;
+ uint128_t pretmp_18;
+ uint128_t prephitmp_19;
<bb 2> [local count: 1073741824]:
- h = *.LC0;
_1 = e_10(D)->b;
if (_1 == 0)
goto <bb 4>; [50.00%]
@@ -44,12 +43,12 @@ void foo (struct S * e)
<bb 3> [local count: 536870912]:
f_11 = e_10(D)->a;
+ pretmp_18 = MEM <uint128_t> [(char * {ref-all})f_11];
<bb 4> [local count: 1073741824]:
- # f_7 = PHI <&h(2), f_11(3)>
+ # prephitmp_19 = PHI <4575657222473777152(2), pretmp_18(3)>
g_12 = e_10(D)->d;
- _13 = MEM <uint128_t> [(char * {ref-all})f_7];
- MEM <uint128_t> [(char * {ref-all})g_12] = _13;
+ MEM <uint128_t> [(char * {ref-all})g_12] = prephitmp_19;
bar ();
_2 = e_10(D)->b;
if (_2 == 0)
@@ -89,7 +88,6 @@ void foo (struct S * e)
__builtin_abort ();
<bb 10> [local count: 1073741824]:
- h ={v} {CLOBBER(eol)};
return;
}
4575657222473777152 is 0x3f8000003f800000 so on big endian that looks
reasonable.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/114605] [14 Regression] wrong code with -march=z13 -O0 since r14-5831
2024-04-05 13:23 [Bug target/114605] New: [14 Regression] wrong code with -march=z13 -O0 since r14-5831 jakub at gcc dot gnu.org
@ 2024-04-05 13:23 ` jakub at gcc dot gnu.org
2024-04-05 13:46 ` jakub at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2024-04-05 13:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114605
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |14.0
Priority|P3 |P1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/114605] [14 Regression] wrong code with -march=z13 -O0 since r14-5831
2024-04-05 13:23 [Bug target/114605] New: [14 Regression] wrong code with -march=z13 -O0 since r14-5831 jakub at gcc dot gnu.org
2024-04-05 13:23 ` [Bug target/114605] " jakub at gcc dot gnu.org
@ 2024-04-05 13:46 ` jakub at gcc dot gnu.org
2024-04-05 14:29 ` jakub at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2024-04-05 13:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114605
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2024-04-05
Status|UNCONFIRMED |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This is a clear bug in s390_const_int_pool_entry_p. It just uses
get_pool_constant but ignores get_pool_mode, which on big-endian is
significant. The function doesn't allow offsets like e.g. simplify-rtx.cc
(avoid_constant_pool_reference), but still needs to deal with mode mismatches.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/114605] [14 Regression] wrong code with -march=z13 -O0 since r14-5831
2024-04-05 13:23 [Bug target/114605] New: [14 Regression] wrong code with -march=z13 -O0 since r14-5831 jakub at gcc dot gnu.org
2024-04-05 13:23 ` [Bug target/114605] " jakub at gcc dot gnu.org
2024-04-05 13:46 ` jakub at gcc dot gnu.org
@ 2024-04-05 14:29 ` jakub at gcc dot gnu.org
2024-04-08 14:22 ` cvs-commit at gcc dot gnu.org
2024-04-08 14:23 ` jakub at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2024-04-05 14:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114605
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 57889
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57889&action=edit
gcc14-pr114605.patch
Untested fix.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/114605] [14 Regression] wrong code with -march=z13 -O0 since r14-5831
2024-04-05 13:23 [Bug target/114605] New: [14 Regression] wrong code with -march=z13 -O0 since r14-5831 jakub at gcc dot gnu.org
` (2 preceding siblings ...)
2024-04-05 14:29 ` jakub at gcc dot gnu.org
@ 2024-04-08 14:22 ` cvs-commit at gcc dot gnu.org
2024-04-08 14:23 ` jakub at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-04-08 14:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114605
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:
https://gcc.gnu.org/g:d5d84487dec06186fd9246b505f44ef68a66d6a2
commit r14-9834-gd5d84487dec06186fd9246b505f44ef68a66d6a2
Author: Jakub Jelinek <jakub@redhat.com>
Date: Mon Apr 8 16:22:13 2024 +0200
s390: Fix s390_const_int_pool_entry_p and movdi peephole2 [PR114605]
The following testcase is miscompiled, because we have initially
a movti which loads the 0x3f8000003f800000ULL TImode constant
from constant pool. Later on we split it into a pair of DImode
loads. Now, for the first load (why just that?, though not stage4
material) we trigger the peephole2 which uses s390_const_int_pool_entry_p.
That function doesn't check at all the constant pool mode though, sees
the constant pool at that address has a CONST_INT value and just assumes
that is the value to return, which is especially wrong for big-endian,
if it is a DImode load from offset 0, it should be loading 0 rather than
0x3f8000003f800000ULL.
The following patch adds checks if we are extracing a MODE_INT mode,
if the constant pool has MODE_INT mode as well, punts if constant pool
has smaller mode size than the extraction one (then it would be UB),
if it has the same mode as before keeps using what it did before,
if constant pool has a larger mode than the one being extracted, uses
simplify_subreg. I'd have used avoid_constant_pool_reference
instead which can handle also offsets into the constant pool constants,
but it can't handle UNSPEC_LTREF.
Another thing is that once that is fixed, we ICE when we extract constant
like 0, ior insn predicate require non-0 constant. So, the patch also
fixes the peephole2 so that if either 32-bit half is zero, it uses a mere
load of the constant into register rather than a pair of such load and ior.
2024-04-08 Jakub Jelinek <jakub@redhat.com>
PR target/114605
* config/s390/s390.cc (s390_const_int_pool_entry_p): Punt
if mem doesn't have MODE_INT mode, or pool constant doesn't
have MODE_INT mode, or if pool constant mode is smaller than
mem mode. If mem mode is different from pool constant mode,
try to simplify subreg. If that doesn't work, punt, if it
does, use the simplified constant instead of the constant pool
constant.
* config/s390/s390.md (movdi from const pool peephole): If
either low or high 32-bit part is zero, just emit move insn
instead of move + ior.
* gcc.dg/pr114605.c: New test.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/114605] [14 Regression] wrong code with -march=z13 -O0 since r14-5831
2024-04-05 13:23 [Bug target/114605] New: [14 Regression] wrong code with -march=z13 -O0 since r14-5831 jakub at gcc dot gnu.org
` (3 preceding siblings ...)
2024-04-08 14:22 ` cvs-commit at gcc dot gnu.org
@ 2024-04-08 14:23 ` jakub at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2024-04-08 14:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114605
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2024-04-05 13:23 [Bug target/114605] New: [14 Regression] wrong code with -march=z13 -O0 since r14-5831 jakub at gcc dot gnu.org
2024-04-05 13:23 ` [Bug target/114605] " jakub at gcc dot gnu.org
2024-04-05 13:46 ` jakub at gcc dot gnu.org
2024-04-05 14:29 ` jakub at gcc dot gnu.org
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