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* [Bug middle-end/19391] New: [4.0 Regression] missed optimization with size of 8 vectors
@ 2005-01-12 6:32 pinskia at gcc dot gnu dot org
2005-01-12 6:34 ` [Bug middle-end/19391] " pinskia at gcc dot gnu dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-01-12 6:32 UTC (permalink / raw)
To: gcc-bugs
We do not generate the vector instructions with the following code on x86_64 (and x86 -msse3):
typedef short mmxw __attribute__ ((vector_size(8)));
typedef int mmxdw __attribute__ ((vector_size(8)));
mmxdw dw;
mmxw w;
void test(){
w+=w;
dw= (mmxdw)w;
}
The code comes from PR 14552 but we don't use the vector unit any more for the addition so we
produce so much crappy code:
movq w(%rip), %xmm0
movabsq $-9223231297218904064, %rax
movq %xmm0, -8(%rsp)
movq -8(%rsp), %rsi
movq %rsi, %rcx
movq %rsi, %rdx
xorq %rsi, %rcx
andq %rax, %rcx
movabsq $9223231297218904063, %rax
andq %rax, %rdx
addq %rdx, %rdx
xorq %rdx, %rcx
movq %rcx, -16(%rsp)
movq -16(%rsp), %xmm0
movq %xmm0, w(%rip)
movq %xmm0, dw(%rip)
ret
Compared to what we got in 3.4:
test:
movq w, %mm1
psllw $1, %mm1
movq %mm1, w
movq w, %mm0
movq %mm0, dw
ret
--
Summary: [4.0 Regression] missed optimization with size of 8
vectors
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Keywords: missed-optimization, ssemmx
Severity: normal
Priority: P2
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: pinskia at gcc dot gnu dot org
CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: x86_64-*-*
OtherBugsDependingO 14552
nThis:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19391
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/19391] [4.0 Regression] missed optimization with size of 8 vectors
2005-01-12 6:32 [Bug middle-end/19391] New: [4.0 Regression] missed optimization with size of 8 vectors pinskia at gcc dot gnu dot org
@ 2005-01-12 6:34 ` pinskia at gcc dot gnu dot org
2005-01-12 9:23 ` steven at gcc dot gnu dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-01-12 6:34 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-01-12 06:34 -------
Note this worked with 20041124.
--
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.0.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19391
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/19391] [4.0 Regression] missed optimization with size of 8 vectors
2005-01-12 6:32 [Bug middle-end/19391] New: [4.0 Regression] missed optimization with size of 8 vectors pinskia at gcc dot gnu dot org
2005-01-12 6:34 ` [Bug middle-end/19391] " pinskia at gcc dot gnu dot org
@ 2005-01-12 9:23 ` steven at gcc dot gnu dot org
2005-01-12 9:54 ` rth at gcc dot gnu dot org
2005-01-12 15:31 ` pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: steven at gcc dot gnu dot org @ 2005-01-12 9:23 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From steven at gcc dot gnu dot org 2005-01-12 09:23 -------
Is this a regression that may be caused by RTH's rewrite?
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |rth at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19391
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/19391] [4.0 Regression] missed optimization with size of 8 vectors
2005-01-12 6:32 [Bug middle-end/19391] New: [4.0 Regression] missed optimization with size of 8 vectors pinskia at gcc dot gnu dot org
2005-01-12 6:34 ` [Bug middle-end/19391] " pinskia at gcc dot gnu dot org
2005-01-12 9:23 ` steven at gcc dot gnu dot org
@ 2005-01-12 9:54 ` rth at gcc dot gnu dot org
2005-01-12 15:31 ` pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: rth at gcc dot gnu dot org @ 2005-01-12 9:54 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From rth at gcc dot gnu dot org 2005-01-12 09:54 -------
Try again with <mmintrin.h> functions.
It is absolutely ESSENTIAL that we do NOT emit mmx vector operations UNLESS
the <mmintrin.h> routines are used. Doing so without the compiler also
being able to insert emms instructions is wrong-code.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19391
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug middle-end/19391] [4.0 Regression] missed optimization with size of 8 vectors
2005-01-12 6:32 [Bug middle-end/19391] New: [4.0 Regression] missed optimization with size of 8 vectors pinskia at gcc dot gnu dot org
` (2 preceding siblings ...)
2005-01-12 9:54 ` rth at gcc dot gnu dot org
@ 2005-01-12 15:31 ` pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-01-12 15:31 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-01-12 15:31 -------
(In reply to comment #3)
> Try again with <mmintrin.h> functions.
>
> It is absolutely ESSENTIAL that we do NOT emit mmx vector operations UNLESS
> the <mmintrin.h> routines are used. Doing so without the compiler also
> being able to insert emms instructions is wrong-code.
Ok, but please add something to the changes page as I had thought I had saw this wording in a patch
but I did not for sure.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |WONTFIX
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19391
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2005-01-12 15:31 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2005-01-12 6:32 [Bug middle-end/19391] New: [4.0 Regression] missed optimization with size of 8 vectors pinskia at gcc dot gnu dot org
2005-01-12 6:34 ` [Bug middle-end/19391] " pinskia at gcc dot gnu dot org
2005-01-12 9:23 ` steven at gcc dot gnu dot org
2005-01-12 9:54 ` rth at gcc dot gnu dot org
2005-01-12 15:31 ` pinskia at gcc dot gnu dot org
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