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* [Bug tree-optimization/52034] New: __builtin_copysign optimization suboptimal
@ 2012-01-29 0:47 drepper.fsp at gmail dot com
2012-01-29 2:40 ` [Bug target/52034] " pinskia at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: drepper.fsp at gmail dot com @ 2012-01-29 0:47 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52034
Bug #: 52034
Summary: __builtin_copysign optimization suboptimal
Classification: Unclassified
Product: gcc
Version: 4.6.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: drepper.fsp@gmail.com
The most trivial __builtin_copysign optimization is not optimal:
double f(double a, double b)
{
return __builtin_copysign(a,b);
}
With gcc 4.6.2 this gets compiled to
movapd %xmm1, %xmm2
andpd .LC0(%rip), %xmm0
andpd .LC1(%rip), %xmm2
orpd %xmm2, %xmm0
ret
There is no reason for %xmm1 to be duplicated to %xmm2. This is sufficient:
andpd .LC0(%rip), %xmm0
andpd .LC1(%rip), %xmm1
orpd %xmm1, %xmm0
ret
The same happens with more complicated code sequences.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/52034] __builtin_copysign optimization suboptimal 2012-01-29 0:47 [Bug tree-optimization/52034] New: __builtin_copysign optimization suboptimal drepper.fsp at gmail dot com @ 2012-01-29 2:40 ` pinskia at gcc dot gnu.org 2012-01-30 9:43 ` rguenth at gcc dot gnu.org ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2012-01-29 2:40 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52034 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target| |x86_64-*-* i?86-*-* Status|UNCONFIRMED |NEW Keywords| |missed-optimization, ra Last reconfirmed| |2012-01-29 Component|tree-optimization |target Ever Confirmed|0 |1 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-01-29 01:27:53 UTC --- Confirmed. This is either the way copysign rtl is done on x86_64 or is a register allocator issue with the copysign rtl. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/52034] __builtin_copysign optimization suboptimal 2012-01-29 0:47 [Bug tree-optimization/52034] New: __builtin_copysign optimization suboptimal drepper.fsp at gmail dot com 2012-01-29 2:40 ` [Bug target/52034] " pinskia at gcc dot gnu.org @ 2012-01-30 9:43 ` rguenth at gcc dot gnu.org 2021-09-04 6:21 ` pinskia at gcc dot gnu.org ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: rguenth at gcc dot gnu.org @ 2012-01-30 9:43 UTC (permalink / raw) To: gcc-bugs http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52034 --- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-30 09:35:37 UTC --- It's an RA issue I think - the RA isn't very clever when it comes to coalescing pseudos with incoming or outgoing fixed regs. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/52034] __builtin_copysign optimization suboptimal 2012-01-29 0:47 [Bug tree-optimization/52034] New: __builtin_copysign optimization suboptimal drepper.fsp at gmail dot com 2012-01-29 2:40 ` [Bug target/52034] " pinskia at gcc dot gnu.org 2012-01-30 9:43 ` rguenth at gcc dot gnu.org @ 2021-09-04 6:21 ` pinskia at gcc dot gnu.org 2021-09-04 6:36 ` pinskia at gcc dot gnu.org 2021-09-04 6:38 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-09-04 6:21 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52034 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=89984 Severity|normal |enhancement --- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- related to PR 89984. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/52034] __builtin_copysign optimization suboptimal 2012-01-29 0:47 [Bug tree-optimization/52034] New: __builtin_copysign optimization suboptimal drepper.fsp at gmail dot com ` (2 preceding siblings ...) 2021-09-04 6:21 ` pinskia at gcc dot gnu.org @ 2021-09-04 6:36 ` pinskia at gcc dot gnu.org 2021-09-04 6:38 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-09-04 6:36 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52034 --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Th ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/52034] __builtin_copysign optimization suboptimal 2012-01-29 0:47 [Bug tree-optimization/52034] New: __builtin_copysign optimization suboptimal drepper.fsp at gmail dot com ` (3 preceding siblings ...) 2021-09-04 6:36 ` pinskia at gcc dot gnu.org @ 2021-09-04 6:38 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-09-04 6:38 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52034 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |11.0 Resolution|--- |FIXED Status|NEW |RESOLVED --- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- This was a scrach_register issue which was fixed in r11-4577. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-09-04 6:38 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-01-29 0:47 [Bug tree-optimization/52034] New: __builtin_copysign optimization suboptimal drepper.fsp at gmail dot com 2012-01-29 2:40 ` [Bug target/52034] " pinskia at gcc dot gnu.org 2012-01-30 9:43 ` rguenth at gcc dot gnu.org 2021-09-04 6:21 ` pinskia at gcc dot gnu.org 2021-09-04 6:36 ` pinskia at gcc dot gnu.org 2021-09-04 6:38 ` pinskia at gcc dot gnu.org
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