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* [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
@ 2024-04-25 7:45 pinskia at gcc dot gnu.org
2024-04-25 8:00 ` [Bug target/114848] " xry111 at gcc dot gnu.org
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-04-25 7:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
Bug ID: 114848
Summary: longarch: epilogue in _Unwind_RaiseException corrupts
return value due to __builtin_eh_return
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Target: longarch64-linux-gnu
I reduced an miscompile for aarch64 inside _Unwind_RaiseException and I noticed
the same issue can be reproduced on powerpc64-linux-gnu and powerpc-linux-gnu.
Reduced testcase:
```
__attribute__((noipa,noinline))
int f(int *a, long offset, void *handler)
{
if (*a == 5)
return 5;
__builtin_eh_return (offset, handler);
}
int main()
{
int t = 5;
if (f(&t, 0, 0) != 5)
__builtin_abort();
}
```
This produces a load (of r4) in the epilogue part for the `return 5` path
(which is reduced from the end of stack path inside _Unwind_RaiseException).
```
bne $r13,$r12,.L2
addi.w $r4,$r0,5 # 0x5
or $r8,$r0,$r0
.L4:
ld.d $r1,$r3,40
.cfi_remember_state
.cfi_restore 1
ld.d $r5,$r3,24
.cfi_restore 5
ld.d $r4,$r3,32
.cfi_restore 4
ld.d $r6,$r3,16
.cfi_restore 6
ld.d $r7,$r3,8
.cfi_restore 7
addi.d $r3,$r3,48
.cfi_def_cfa_offset 0
add.d $r3,$r3,$r8
jr $r1
```
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
@ 2024-04-25 8:00 ` xry111 at gcc dot gnu.org
2024-04-25 8:04 ` pinskia at gcc dot gnu.org
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: xry111 at gcc dot gnu.org @ 2024-04-25 8:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
Xi Ruoyao <xry111 at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |xry111 at gcc dot gnu.org
--- Comment #1 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
Hmm, AFAIK this should be already fixed with r14-6440?
I cannot reproduce it with r14-9823 but maybe it has regressed again in the
recent weeks.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
2024-04-25 8:00 ` [Bug target/114848] " xry111 at gcc dot gnu.org
@ 2024-04-25 8:04 ` pinskia at gcc dot gnu.org
2024-04-25 8:11 ` [Bug target/114848] loongarch: " xry111 at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-04-25 8:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Version|14.0 |13.2.0
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Xi Ruoyao from comment #1)
> Hmm, AFAIK this should be already fixed with r14-6440?
>
> I cannot reproduce it with r14-9823 but maybe it has regressed again in the
> recent weeks.
Oh I only tested gcc 13.2.0. If it is fixed you can close it.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] loongarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
2024-04-25 8:00 ` [Bug target/114848] " xry111 at gcc dot gnu.org
2024-04-25 8:04 ` pinskia at gcc dot gnu.org
@ 2024-04-25 8:11 ` xry111 at gcc dot gnu.org
2024-04-25 8:21 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: xry111 at gcc dot gnu.org @ 2024-04-25 8:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
Xi Ruoyao <xry111 at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|longarch: epilogue in |loongarch: epilogue in
|_Unwind_RaiseException |_Unwind_RaiseException
|corrupts return value due |corrupts return value due
|to __builtin_eh_return |to __builtin_eh_return
--- Comment #3 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> (In reply to Xi Ruoyao from comment #1)
> > Hmm, AFAIK this should be already fixed with r14-6440?
> >
> > I cannot reproduce it with r14-9823 but maybe it has regressed again in the
> > recent weeks.
>
> Oh I only tested gcc 13.2.0. If it is fixed you can close it.
Hmm it looks like we need a backport to releases/gcc-13 (and 12?)
I thought the bug was introduced by my shrink-wrap change (r14-545) so I didn't
proposed a backport. But it seems I was wrong and the bug exists even before
r14-545.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] loongarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
` (2 preceding siblings ...)
2024-04-25 8:11 ` [Bug target/114848] loongarch: " xry111 at gcc dot gnu.org
@ 2024-04-25 8:21 ` pinskia at gcc dot gnu.org
2024-04-27 9:05 ` chenglulu at loongson dot cn
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-04-25 8:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Also it looks like I messed up comment #0 and forgot to change powerpc to
longarch64 :). That is what I get for trying to split this all out.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] loongarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
` (3 preceding siblings ...)
2024-04-25 8:21 ` pinskia at gcc dot gnu.org
@ 2024-04-27 9:05 ` chenglulu at loongson dot cn
2024-04-30 1:09 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: chenglulu at loongson dot cn @ 2024-04-27 9:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
--- Comment #5 from chenglulu <chenglulu at loongson dot cn> ---
(In reply to Xi Ruoyao from comment #3)
> (In reply to Andrew Pinski from comment #2)
> > (In reply to Xi Ruoyao from comment #1)
> > > Hmm, AFAIK this should be already fixed with r14-6440?
> > >
> > > I cannot reproduce it with r14-9823 but maybe it has regressed again in the
> > > recent weeks.
> >
> > Oh I only tested gcc 13.2.0. If it is fixed you can close it.
>
> Hmm it looks like we need a backport to releases/gcc-13 (and 12?)
I have backpointed r14-6440 to gcc-13 and gcc-12 and am testing
>
> I thought the bug was introduced by my shrink-wrap change (r14-545) so I
> didn't proposed a backport. But it seems I was wrong and the bug exists
> even before r14-545.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] loongarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
` (4 preceding siblings ...)
2024-04-27 9:05 ` chenglulu at loongson dot cn
@ 2024-04-30 1:09 ` cvs-commit at gcc dot gnu.org
2024-04-30 1:11 ` cvs-commit at gcc dot gnu.org
2024-04-30 1:20 ` xry111 at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-04-30 1:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by LuluCheng
<chenglulu@gcc.gnu.org>:
https://gcc.gnu.org/g:bb78099d2624b52c781ed6e5d85e43d54c3cda1a
commit r12-10403-gbb78099d2624b52c781ed6e5d85e43d54c3cda1a
Author: Yang Yujie <yangyujie@loongson.cn>
Date: Fri Dec 8 18:01:18 2023 +0800
LoongArch: Fix eh_return epilogue for normal returns.
On LoongArch, the regitsters $r4 - $r7 (EH_RETURN_DATA_REGNO) will be saved
and restored in the function prologue and epilogue if the given function
calls
__builtin_eh_return. This causes the return value to be overwritten on
normal
return paths and breaks a rare case of libgcc's _Unwind_RaiseException.
gcc/ChangeLog:
PR target/114848
* config/loongarch/loongarch.cc: Do not restore the saved eh_return
data registers ($r4-$r7) for a normal return of a function that
calls
__builtin_eh_return elsewhere.
* config/loongarch/loongarch-protos.h: Same.
* config/loongarch/loongarch.md: Same.
gcc/testsuite/ChangeLog:
* gcc.target/loongarch/eh_return-normal-return.c: New test.
(cherry picked from commit 4b421728289e6f1caa0dfaa953a11698ab95d37d)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] loongarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
` (5 preceding siblings ...)
2024-04-30 1:09 ` cvs-commit at gcc dot gnu.org
@ 2024-04-30 1:11 ` cvs-commit at gcc dot gnu.org
2024-04-30 1:20 ` xry111 at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2024-04-30 1:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by LuluCheng
<chenglulu@gcc.gnu.org>:
https://gcc.gnu.org/g:88f22217521564e1a956e14ac55456caa160e055
commit r13-8661-g88f22217521564e1a956e14ac55456caa160e055
Author: Yang Yujie <yangyujie@loongson.cn>
Date: Fri Dec 8 18:01:18 2023 +0800
LoongArch: Fix eh_return epilogue for normal returns.
On LoongArch, the regitsters $r4 - $r7 (EH_RETURN_DATA_REGNO) will be saved
and restored in the function prologue and epilogue if the given function
calls
__builtin_eh_return. This causes the return value to be overwritten on
normal
return paths and breaks a rare case of libgcc's _Unwind_RaiseException.
gcc/ChangeLog:
PR target/114848
* config/loongarch/loongarch.cc: Do not restore the saved eh_return
data registers ($r4-$r7) for a normal return of a function that
calls
__builtin_eh_return elsewhere.
* config/loongarch/loongarch-protos.h: Same.
* config/loongarch/loongarch.md: Same.
gcc/testsuite/ChangeLog:
* gcc.target/loongarch/eh_return-normal-return.c: New test.
(cherry picked from commit 4b421728289e6f1caa0dfaa953a11698ab95d37d)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/114848] loongarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return
2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
` (6 preceding siblings ...)
2024-04-30 1:11 ` cvs-commit at gcc dot gnu.org
@ 2024-04-30 1:20 ` xry111 at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: xry111 at gcc dot gnu.org @ 2024-04-30 1:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114848
Xi Ruoyao <xry111 at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Target Milestone|--- |12.4
Status|UNCONFIRMED |RESOLVED
--- Comment #8 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
Fixed for 12 and 13.
^ permalink raw reply [flat|nested] 9+ messages in thread
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2024-04-25 7:45 [Bug target/114848] New: longarch: epilogue in _Unwind_RaiseException corrupts return value due to __builtin_eh_return pinskia at gcc dot gnu.org
2024-04-25 8:00 ` [Bug target/114848] " xry111 at gcc dot gnu.org
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2024-04-25 8:11 ` [Bug target/114848] loongarch: " xry111 at gcc dot gnu.org
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