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* [Bug tree-optimization/95738] New: Failure to optimize comparison of float after sign xor to unsigned comparison
@ 2020-06-18 9:41 gabravier at gmail dot com
2021-04-26 1:13 ` [Bug tree-optimization/95738] Failure to optimize comparison of vector " pinskia at gcc dot gnu.org
2021-08-07 7:44 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: gabravier at gmail dot com @ 2020-06-18 9:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95738
Bug ID: 95738
Summary: Failure to optimize comparison of float after sign xor
to unsigned comparison
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
typedef int64_t v2i64 __attribute__((vector_size(16)));
typedef uint64_t v2u64 __attribute__((vector_size(16)));
v2i64 f(v2i64 a, v2i64 b)
{
auto sign = (v2i64){(int64_t)0x8000000000000000u,
(int64_t)0x8000000000000000u};
return (a ^ sign) > (b ^ sign);
}
This can be optimized to `(v2u64)a > (v2u64)b`. This transformation is done by
LLVM, but not by GCC.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/95738] Failure to optimize comparison of vector after sign xor to unsigned comparison
2020-06-18 9:41 [Bug tree-optimization/95738] New: Failure to optimize comparison of float after sign xor to unsigned comparison gabravier at gmail dot com
@ 2021-04-26 1:13 ` pinskia at gcc dot gnu.org
2021-08-07 7:44 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-04-26 1:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95738
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|Failure to optimize |Failure to optimize
|comparison of float after |comparison of vector after
|sign xor to unsigned |sign xor to unsigned
|comparison |comparison
Severity|normal |enhancement
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Vectors optimizations are less likely to implemented really.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/95738] Failure to optimize comparison of vector after sign xor to unsigned comparison
2020-06-18 9:41 [Bug tree-optimization/95738] New: Failure to optimize comparison of float after sign xor to unsigned comparison gabravier at gmail dot com
2021-04-26 1:13 ` [Bug tree-optimization/95738] Failure to optimize comparison of vector " pinskia at gcc dot gnu.org
@ 2021-08-07 7:44 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-07 7:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95738
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-08-07
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
We don't even do the scalar one:
int64_t f(int64_t a, int64_t b)
{
auto sign = (int64_t)0x8000000000000000u;
return (a ^ sign) > (b ^ sign);
}
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-08-07 7:44 UTC | newest]
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2020-06-18 9:41 [Bug tree-optimization/95738] New: Failure to optimize comparison of float after sign xor to unsigned comparison gabravier at gmail dot com
2021-04-26 1:13 ` [Bug tree-optimization/95738] Failure to optimize comparison of vector " pinskia at gcc dot gnu.org
2021-08-07 7:44 ` pinskia at gcc dot gnu.org
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