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* [Bug tree-optimization/112272] New: suboptimal zero-initialization of struct of mixed pointer and integer types
@ 2023-10-29 8:13 lh_mouse at 126 dot com
2023-10-29 16:32 ` [Bug tree-optimization/112272] " pinskia at gcc dot gnu.org
2023-11-04 5:57 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: lh_mouse at 126 dot com @ 2023-10-29 8:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112272
Bug ID: 112272
Summary: suboptimal zero-initialization of struct of mixed
pointer and integer types
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: lh_mouse at 126 dot com
Target Milestone: ---
Testcase:
(https://gcc.godbolt.org/z/97cThnszM)
```
struct data_mixed
{
int* p1;
int* p2;
__INTPTR_TYPE__ i3;
int* p4;
constexpr data_mixed() noexcept : p1(), p2(), i3(), p4() { }
};
data_mixed
create_data_mixed()
{
return {}; // somehow suboptimal ↓↓
// mov QWORD PTR [rdi+16], 0
// mov QWORD PTR [rdi+24], 0
// vmovdqu XMMWORD PTR [rdi], xmm0
}
struct data_ptrs
{
int* p1;
int* p2;
void* p3;
int* p4;
constexpr data_ptrs() noexcept : p1(), p2(), p3(), p4() { }
};
data_ptrs
create_data_ptrs()
{
return {}; // vmovdqu YMMWORD PTR [rdi], ymm0
}
struct data_ints
{
__INTPTR_TYPE__ p1;
__INTPTR_TYPE__ p2;
__INTPTR_TYPE__ p3;
__INTPTR_TYPE__ p4;
constexpr data_ints() noexcept : p1(), p2(), p3(), p4() { }
};
data_ints
create_data_ints()
{
return {}; // vmovdqu YMMWORD PTR [rdi], ymm0
}
```
I believe these structs should be initialized in the same way, by storing a
zero YMM register. However mixed use of pointer and integer types seems to
prevent that. This is not specific to GCC 13; in GCC 12 it used to prevent
vectorization completely.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/112272] suboptimal zero-initialization of struct of mixed pointer and integer types
2023-10-29 8:13 [Bug tree-optimization/112272] New: suboptimal zero-initialization of struct of mixed pointer and integer types lh_mouse at 126 dot com
@ 2023-10-29 16:32 ` pinskia at gcc dot gnu.org
2023-11-04 5:57 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-10-29 16:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112272
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/112272] suboptimal zero-initialization of struct of mixed pointer and integer types
2023-10-29 8:13 [Bug tree-optimization/112272] New: suboptimal zero-initialization of struct of mixed pointer and integer types lh_mouse at 126 dot com
2023-10-29 16:32 ` [Bug tree-optimization/112272] " pinskia at gcc dot gnu.org
@ 2023-11-04 5:57 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-11-04 5:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112272
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2023-11-04
Blocks| |53947
Status|UNCONFIRMED |NEW
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
I don't know why the SLP vectorizer rejects it.
Though I wonder why store merging also rejects it for a cost reason ...
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-10-29 8:13 [Bug tree-optimization/112272] New: suboptimal zero-initialization of struct of mixed pointer and integer types lh_mouse at 126 dot com
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2023-11-04 5:57 ` pinskia at gcc dot gnu.org
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