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* [Bug target/106324] New: ptrue not reused between vector instructions and predicate instructions
@ 2022-07-16 13:05 yyc1992 at gmail dot com
2022-07-18 7:46 ` [Bug target/106324] " rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: yyc1992 at gmail dot com @ 2022-07-16 13:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106324
Bug ID: 106324
Summary: ptrue not reused between vector instructions and
predicate instructions
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: yyc1992 at gmail dot com
Target Milestone: ---
The following code has two use of `svptrue_b64()`s and none of the instructions
using them should be clearning it so only one `ptrue` instruction should be
needed.
```
svfloat64_t test(svbool_t pg, svfloat64_t a, svfloat64_t b)
{
auto d = svdiv_m(svptrue_b64(), a, b);
return svmul_m(svnot_z(svptrue_b64(), pg), d, d);
}
```
However, the code generated is,
```
ptrue p2.b, all
ptrue p1.d, all
fdiv z0.d, p2/m, z0.d, z1.d
not p0.b, p1/z, p0.b
fmul z0.d, p0/m, z0.d, z0.d
ret
```
which has an extra `ptrue`.
OTOH, clang generates,
```
ptrue p1.d
fdiv z0.d, p1/m, z0.d, z1.d
not p0.b, p1/z, p0.b
fmul z0.d, p0/m, z0.d, z0.d
ret
```
and the same `ptrue` is reused in both instructions.
This seems to be caused by gcc insisting on using `svptrue_b8` for the svnot
which does not seem necessary here especially since _b64 is explicitly
requested. Changing svptrue_b64 to svptrue_b8 in the code fixes the issue.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/106324] ptrue not reused between vector instructions and predicate instructions
2022-07-16 13:05 [Bug target/106324] New: ptrue not reused between vector instructions and predicate instructions yyc1992 at gmail dot com
@ 2022-07-18 7:46 ` rguenth at gcc dot gnu.org
2022-07-18 8:28 ` ktkachov at gcc dot gnu.org
2022-07-18 13:29 ` yyc1992 at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2022-07-18 7:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106324
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target| |aarch64
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
guessing aarch64
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/106324] ptrue not reused between vector instructions and predicate instructions
2022-07-16 13:05 [Bug target/106324] New: ptrue not reused between vector instructions and predicate instructions yyc1992 at gmail dot com
2022-07-18 7:46 ` [Bug target/106324] " rguenth at gcc dot gnu.org
@ 2022-07-18 8:28 ` ktkachov at gcc dot gnu.org
2022-07-18 13:29 ` yyc1992 at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: ktkachov at gcc dot gnu.org @ 2022-07-18 8:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106324
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2022-07-18
Ever confirmed|0 |1
CC| |ktkachov at gcc dot gnu.org
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
--- Comment #2 from ktkachov at gcc dot gnu.org ---
Confirmed.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/106324] ptrue not reused between vector instructions and predicate instructions
2022-07-16 13:05 [Bug target/106324] New: ptrue not reused between vector instructions and predicate instructions yyc1992 at gmail dot com
2022-07-18 7:46 ` [Bug target/106324] " rguenth at gcc dot gnu.org
2022-07-18 8:28 ` ktkachov at gcc dot gnu.org
@ 2022-07-18 13:29 ` yyc1992 at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: yyc1992 at gmail dot com @ 2022-07-18 13:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106324
--- Comment #3 from Yichao Yu <yyc1992 at gmail dot com> ---
Actually I just realized that the not instruction used the .d version as
requested, the vector instruction didn’t….. I got it reversed in the original
post……
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-07-18 13:29 UTC | newest]
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2022-07-16 13:05 [Bug target/106324] New: ptrue not reused between vector instructions and predicate instructions yyc1992 at gmail dot com
2022-07-18 7:46 ` [Bug target/106324] " rguenth at gcc dot gnu.org
2022-07-18 8:28 ` ktkachov at gcc dot gnu.org
2022-07-18 13:29 ` yyc1992 at gmail dot com
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