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* [Bug rtl-optimization/23812] New: swapping DImode halves produces poor x86 register allocation
@ 2005-09-11 2:01 raeburn at raeburn dot org
2005-09-11 14:22 ` [Bug rtl-optimization/23812] " pinskia at gcc dot gnu dot org
2005-09-12 14:31 ` pinskia at gcc dot gnu dot org
0 siblings, 2 replies; 3+ messages in thread
From: raeburn at raeburn dot org @ 2005-09-11 2:01 UTC (permalink / raw)
To: gcc-bugs
(CVS sources, ~6AM this morning US/eastern)
typedef unsigned long long uint64_t;
uint64_t foo (uint64_t n) {
return (n >> 32) | (n << 32);
}
compiled with -O9 -fomit-frame-pointer:
foo:
pushl %ebx
movl 12(%esp), %ebx
movl 8(%esp), %ecx
movl %ebx, %eax
popl %ebx
movl %ecx, %edx
ret
It should've been able to load 4(%esp) and 8(%esp) into %edx and %eax respectively, without using the
extra stack slot to save ebx.
--
Summary: swapping DImode halves produces poor x86 register
allocation
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: raeburn at raeburn dot org
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23812
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug rtl-optimization/23812] swapping DImode halves produces poor x86 register allocation
2005-09-11 2:01 [Bug rtl-optimization/23812] New: swapping DImode halves produces poor x86 register allocation raeburn at raeburn dot org
@ 2005-09-11 14:22 ` pinskia at gcc dot gnu dot org
2005-09-12 14:31 ` pinskia at gcc dot gnu dot org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-09-11 14:22 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-09-11 14:22 -------
This is the normal subreg problem with the current RA. There are a couple other bugs about this
already opened.
--
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Keywords| |missed-optimization, ra
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23812
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug rtl-optimization/23812] swapping DImode halves produces poor x86 register allocation
2005-09-11 2:01 [Bug rtl-optimization/23812] New: swapping DImode halves produces poor x86 register allocation raeburn at raeburn dot org
2005-09-11 14:22 ` [Bug rtl-optimization/23812] " pinskia at gcc dot gnu dot org
@ 2005-09-12 14:31 ` pinskia at gcc dot gnu dot org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-09-12 14:31 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-09-12 14:31 -------
Confirmed, basicially the same issue as PR 15792.
--
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |15792
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
Last reconfirmed|0000-00-00 00:00:00 |2005-09-12 14:31:14
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23812
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2005-09-12 14:31 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-09-11 2:01 [Bug rtl-optimization/23812] New: swapping DImode halves produces poor x86 register allocation raeburn at raeburn dot org
2005-09-11 14:22 ` [Bug rtl-optimization/23812] " pinskia at gcc dot gnu dot org
2005-09-12 14:31 ` pinskia at gcc dot gnu dot org
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