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* [Bug rtl-optimization/94860] New: Failure to recognize bzhi pattern
@ 2020-04-29 20:09 gabravier at gmail dot com
2020-04-29 20:48 ` [Bug rtl-optimization/94860] " jakub at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: gabravier at gmail dot com @ 2020-04-29 20:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94860
Bug ID: 94860
Summary: Failure to recognize bzhi pattern
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
uint32_t bzhi32(uint32_t x, uint32_t y)
{
return ((x << (32 - y)) >> (32 - y));
}
LLVM with -O3 -mbmi2 optimizes this to :
bzhi32(unsigned int, unsigned int): # @bzhi32(unsigned int, unsigned int)
bzhi eax, edi, esi
ret
GCC outputs this :
bzhi32(unsigned int, unsigned int):
mov eax, 32
sub eax, esi
shlx edi, edi, eax
shrx eax, edi, eax
ret
It should be optimized down to bzhi.
This optimization can be applied to :
- x86-64 (with bzhi)
- i686 (with bzhi)
- AMDGCN (with v_bfe_u32)
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug rtl-optimization/94860] Failure to recognize bzhi pattern 2020-04-29 20:09 [Bug rtl-optimization/94860] New: Failure to recognize bzhi pattern gabravier at gmail dot com @ 2020-04-29 20:48 ` jakub at gcc dot gnu.org 2020-04-29 21:05 ` [Bug target/94860] " pinskia at gcc dot gnu.org 2020-04-30 6:52 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: jakub at gcc dot gnu.org @ 2020-04-29 20:48 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94860 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> --- PR93346 contains a different pattern that GCC 10 now matches as bzhi. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/94860] Failure to recognize bzhi pattern 2020-04-29 20:09 [Bug rtl-optimization/94860] New: Failure to recognize bzhi pattern gabravier at gmail dot com 2020-04-29 20:48 ` [Bug rtl-optimization/94860] " jakub at gcc dot gnu.org @ 2020-04-29 21:05 ` pinskia at gcc dot gnu.org 2020-04-30 6:52 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2020-04-29 21:05 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94860 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |missed-optimization Severity|normal |enhancement Component|rtl-optimization |target Depends on| |93346 Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93346 [Bug 93346] gcc does not generate BZHI ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/94860] Failure to recognize bzhi pattern 2020-04-29 20:09 [Bug rtl-optimization/94860] New: Failure to recognize bzhi pattern gabravier at gmail dot com 2020-04-29 20:48 ` [Bug rtl-optimization/94860] " jakub at gcc dot gnu.org 2020-04-29 21:05 ` [Bug target/94860] " pinskia at gcc dot gnu.org @ 2020-04-30 6:52 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2020-04-30 6:52 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94860 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2020-04-30 Status|UNCONFIRMED |NEW Ever confirmed|0 |1 Target| |x86_64-*-* i?86-*-* gcn --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-04-30 6:52 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-04-29 20:09 [Bug rtl-optimization/94860] New: Failure to recognize bzhi pattern gabravier at gmail dot com 2020-04-29 20:48 ` [Bug rtl-optimization/94860] " jakub at gcc dot gnu.org 2020-04-29 21:05 ` [Bug target/94860] " pinskia at gcc dot gnu.org 2020-04-30 6:52 ` rguenth at gcc dot gnu.org
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