public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug tree-optimization/109764] New: V2SI multiply high is not vectorized on x86_64
@ 2023-05-07 16:21 ubizjak at gmail dot com
2023-05-07 16:23 ` [Bug tree-optimization/109764] " ubizjak at gmail dot com
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: ubizjak at gmail dot com @ 2023-05-07 16:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109764
Bug ID: 109764
Summary: V2SI multiply high is not vectorized on x86_64
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ubizjak at gmail dot com
Target Milestone: ---
The folowing testcase:
--cut here--
#define N 2
unsigned int ur[N], ua[N], ub[N];
void mulh (void)
{
int i;
for (i = 0; i < N; i++)
ur[i] = ((unsigned long) ua[i] * ub[i]) >> 32;
}
void mulh_slp (void)
{
ur[0] = ((unsigned long) ua[0] * ub[0]) >> 32;
ur[1] = ((unsigned long) ua[1] * ub[1]) >> 32;
}
--cut here--
should vectorize on x86_64 with the patch I'm going to attach, and with
-fno-vect-cost-model. The compiler however does not even consider
"<s>mulv2si3_highpart" pattern.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/109764] V2SI multiply high is not vectorized on x86_64
2023-05-07 16:21 [Bug tree-optimization/109764] New: V2SI multiply high is not vectorized on x86_64 ubizjak at gmail dot com
@ 2023-05-07 16:23 ` ubizjak at gmail dot com
2023-05-08 7:19 ` rguenth at gcc dot gnu.org
2023-05-08 8:09 ` ubizjak at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: ubizjak at gmail dot com @ 2023-05-07 16:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109764
--- Comment #1 from Uroš Bizjak <ubizjak at gmail dot com> ---
Created attachment 55017
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55017&action=edit
Patch that adds <s>mulv2si3_highpart expander
The compiler should vectorize the testcase using "<s>mulv2si3_highpart"
expander.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/109764] V2SI multiply high is not vectorized on x86_64
2023-05-07 16:21 [Bug tree-optimization/109764] New: V2SI multiply high is not vectorized on x86_64 ubizjak at gmail dot com
2023-05-07 16:23 ` [Bug tree-optimization/109764] " ubizjak at gmail dot com
@ 2023-05-08 7:19 ` rguenth at gcc dot gnu.org
2023-05-08 8:09 ` ubizjak at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2023-05-08 7:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109764
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2023-05-08
Blocks| |53947
Target| |x86_64-*-* i?86-*-*
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed. Pattern recog recognizes the widening multiplication but not a
highpart multiplication. That's currently missing.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/109764] V2SI multiply high is not vectorized on x86_64
2023-05-07 16:21 [Bug tree-optimization/109764] New: V2SI multiply high is not vectorized on x86_64 ubizjak at gmail dot com
2023-05-07 16:23 ` [Bug tree-optimization/109764] " ubizjak at gmail dot com
2023-05-08 7:19 ` rguenth at gcc dot gnu.org
@ 2023-05-08 8:09 ` ubizjak at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: ubizjak at gmail dot com @ 2023-05-08 8:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109764
--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Richard Biener from comment #2)
> Confirmed. Pattern recog recognizes the widening multiplication but not a
> highpart multiplication. That's currently missing.
Please note that the following testcase that multiplies short -> int:
--cut here--
#define N 2
unsigned short ur[N], ua[N], ub[N];
void mulh (void)
{
int i;
for (i = 0; i < N; i++)
ur[i] = ((unsigned int) ua[i] * ub[i]) >> 16;
}
void mulh_slp (void)
{
ur[0] = ((unsigned int) ua[0] * ub[0]) >> 16;
ur[1] = ((unsigned int) ua[1] * ub[1]) >> 16;
}
--cut here--
vectorizes with -O2 -fno-vec-cost-model via .MULH:
vect__15.6_1 = MEM <vector(2) short unsigned int> [(short unsigned int
*)&ua];
vect__17.9_3 = MEM <vector(2) short unsigned int> [(short unsigned int
*)&ub];
vect_patt_34.10_5 = .MULH (vect__15.6_1, vect__17.9_3);
MEM <vector(2) short unsigned int> [(short unsigned int *)&ur] =
vect_patt_34.10_5;
and generates expected:
movd ua(%rip), %xmm0
movd ub(%rip), %xmm1
pmulhuw %xmm1, %xmm0
movd %xmm0, ur(%rip)
in both cases.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-05-08 8:09 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-05-07 16:21 [Bug tree-optimization/109764] New: V2SI multiply high is not vectorized on x86_64 ubizjak at gmail dot com
2023-05-07 16:23 ` [Bug tree-optimization/109764] " ubizjak at gmail dot com
2023-05-08 7:19 ` rguenth at gcc dot gnu.org
2023-05-08 8:09 ` ubizjak at gmail dot com
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).