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* [Bug target/96864] New: loop not vectorized due to cost model
@ 2020-08-31 10:15 crazylht at gmail dot com
2020-08-31 13:05 ` [Bug target/96864] loop not vectorized due AVX512 condition handling rguenth at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: crazylht at gmail dot com @ 2020-08-31 10:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96864
Bug ID: 96864
Summary: loop not vectorized due to cost model
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: crazylht at gmail dot com
CC: hjl.tools at gmail dot com
Target Milestone: ---
cat test.c
---
double d1[1024], d2[1024];
char c1[1024];
int test4(int n)
{
int i;
for (int i = 0; i < 1024; i++)
c1[i] = d1[i] > d2[i] ? c1[i] : 1;
}
---
loop is not vectorized with under -mtune=skylake-avx512 but success with
-mtune=generic
Refer to https://godbolt.org/z/xPGhTh
output of -fopt-info-all
---
Unit growth for small function inlining: 16->16 (0%)
Inlined 0 calls, eliminated 0 functions
test.c:6:5: missed: couldn't vectorize loop
test.c:7:17: missed: not vectorized: no vectype for stmt: _1 = d1[i_13];
scalar_type: double
test.c:6:5: note: ***** Analysis failed with vector mode V4DF
test.c:6:5: note: ***** Skipping vector mode V32QI, which would repeat the
analysis for V4DF
test.c:3:5: note: vectorized 0 loops in function.
test.c:3:5: note: ***** Analysis failed with vector mode VOID
test.c:7:13: note: ***** Analysis failed with vector mode V4DF
test.c:7:13: note: ***** Skipping vector mode V32QI, which would repeat the
analysis for V4DF
test.c:7:13: note: ***** Analysis failed with vector mode V32QI
test.c:7:13: note: ***** Skipping vector mode V32QI, which would repeat the
analysis for V32QI
test.c:6:5: note: ***** Analysis failed with vector mode V32QI
test.c:6:5: note: ***** Skipping vector mode V32QI, which would repeat the
analysis for V32QI
test.c:6:5: note: ***** Analysis failed with vector mode VOID
test.c:8:1: note: ***** Analysis failed with vector mode VOID
---
Seems problem of cost model.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/96864] loop not vectorized due AVX512 condition handling
2020-08-31 10:15 [Bug target/96864] New: loop not vectorized due to cost model crazylht at gmail dot com
@ 2020-08-31 13:05 ` rguenth at gcc dot gnu.org
2022-02-15 6:46 ` crazylht at gmail dot com
2022-02-15 6:46 ` crazylht at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-08-31 13:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96864
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Summary|loop not vectorized due to |loop not vectorized due
|cost model |AVX512 condition handling
Blocks| |53947
Keywords| |missed-optimization
Target| |x86_64-*-* i?86-*-*
Ever confirmed|0 |1
Last reconfirmed| |2020-08-31
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
t.c:3:5: missed: not vectorized: relevant stmt not supported: patt_25 =
(<signed-boolean:1>) patt_24;
t.c:6:5: missed: bad operation or unsupported loop bound.
t.c:6:5: note: ***** Analysis failed with vector mode V4DF
it's more a bad pattern for condition vectorization and AVX512 it seems.
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 target/96864] loop not vectorized due AVX512 condition handling
2020-08-31 10:15 [Bug target/96864] New: loop not vectorized due to cost model crazylht at gmail dot com
2020-08-31 13:05 ` [Bug target/96864] loop not vectorized due AVX512 condition handling rguenth at gcc dot gnu.org
@ 2022-02-15 6:46 ` crazylht at gmail dot com
2022-02-15 6:46 ` crazylht at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: crazylht at gmail dot com @ 2022-02-15 6:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96864
--- Comment #2 from Hongtao.liu <crazylht at gmail dot com> ---
Fixed in GCC12 by r12-6756-g8bc700f4c3fbe405413db02281ef2918bfa831fc.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/96864] loop not vectorized due AVX512 condition handling
2020-08-31 10:15 [Bug target/96864] New: loop not vectorized due to cost model crazylht at gmail dot com
2020-08-31 13:05 ` [Bug target/96864] loop not vectorized due AVX512 condition handling rguenth at gcc dot gnu.org
2022-02-15 6:46 ` crazylht at gmail dot com
@ 2022-02-15 6:46 ` crazylht at gmail dot com
2 siblings, 0 replies; 4+ messages in thread
From: crazylht at gmail dot com @ 2022-02-15 6:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96864
Hongtao.liu <crazylht at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-08-31 10:15 [Bug target/96864] New: loop not vectorized due to cost model crazylht at gmail dot com
2020-08-31 13:05 ` [Bug target/96864] loop not vectorized due AVX512 condition handling rguenth at gcc dot gnu.org
2022-02-15 6:46 ` crazylht at gmail dot com
2022-02-15 6:46 ` crazylht at gmail dot com
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