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* [Bug c/66740] New: omp simd reduction miscompiles at -O3 with AVX (recent regression)
@ 2015-07-02 12:42 tprince at computer dot org
2015-07-02 12:43 ` [Bug c/66740] " tprince at computer dot org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: tprince at computer dot org @ 2015-07-02 12:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66740
Bug ID: 66740
Summary: omp simd reduction miscompiles at -O3 with AVX (recent
regression)
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: tprince at computer dot org
Target Milestone: ---
Created attachment 35897
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35897&action=edit
f2c include file
This regression is new in the last 2 weeks.
gcc -O3 -march=sandybridge -std=c99 -D__assume_aligned= -fopenmp -c s115.c
is miscompiled (bad numerical results when run under test harness).
It is OK at -O2 or with -march=westmere, or with the omp directive disabled.
It doesn't vectorize without the omp directive. It fails the same with
-march=haswell.
Similar versions using inner_product or Fortran dot_product are vectorizing
correctly without omp simd.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c/66740] omp simd reduction miscompiles at -O3 with AVX (recent regression)
2015-07-02 12:42 [Bug c/66740] New: omp simd reduction miscompiles at -O3 with AVX (recent regression) tprince at computer dot org
@ 2015-07-02 12:43 ` tprince at computer dot org
2015-07-02 12:46 ` tprince at computer dot org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: tprince at computer dot org @ 2015-07-02 12:43 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66740
--- Comment #1 from tprince at computer dot org ---
Created attachment 35898
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35898&action=edit
C source
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c/66740] omp simd reduction miscompiles at -O3 with AVX (recent regression)
2015-07-02 12:42 [Bug c/66740] New: omp simd reduction miscompiles at -O3 with AVX (recent regression) tprince at computer dot org
2015-07-02 12:43 ` [Bug c/66740] " tprince at computer dot org
@ 2015-07-02 12:46 ` tprince at computer dot org
2015-07-02 12:48 ` tprince at computer dot org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: tprince at computer dot org @ 2015-07-02 12:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66740
--- Comment #2 from tprince at computer dot org ---
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/local/gcc6.0/libexec/gcc/x86_64-unknown-cygwin/6.0.0/lt
o-wrapper.exe
Target: x86_64-unknown-cygwin
Configured with: ../configure --prefix=/usr/local/gcc6.0 --enable-languages='c
c
++ fortran' --enable-libgomp --enable-threads=posix --with-dwarf2
--without-libi
conv-prefix --without-libintl-prefix --with-system-zlib --disable-werror
--witho
ut-cloog --without-isl
Thread model: posix
gcc version 6.0.0 20150630 (experimental) (GCC)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c/66740] omp simd reduction miscompiles at -O3 with AVX (recent regression)
2015-07-02 12:42 [Bug c/66740] New: omp simd reduction miscompiles at -O3 with AVX (recent regression) tprince at computer dot org
2015-07-02 12:43 ` [Bug c/66740] " tprince at computer dot org
2015-07-02 12:46 ` tprince at computer dot org
@ 2015-07-02 12:48 ` tprince at computer dot org
2015-07-02 13:57 ` [Bug tree-optimization/66740] [6 Regression] " rguenth at gcc dot gnu.org
2015-07-10 23:25 ` tprince at computer dot org
4 siblings, 0 replies; 6+ messages in thread
From: tprince at computer dot org @ 2015-07-02 12:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66740
--- Comment #3 from tprince at computer dot org ---
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/local/gcc6.0/libexec/gcc/x86_64-unknown-cygwin/6.0.0/lt
o-wrapper.exe
Target: x86_64-unknown-cygwin
Configured with: ../configure --prefix=/usr/local/gcc6.0 --enable-languages='c
c
++ fortran' --enable-libgomp --enable-threads=posix --with-dwarf2
--without-libi
conv-prefix --without-libintl-prefix --with-system-zlib --disable-werror
--witho
ut-cloog --without-isl
Thread model: posix
gcc version 6.0.0 20150630 (experimental) (GCC)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/66740] [6 Regression] omp simd reduction miscompiles at -O3 with AVX (recent regression)
2015-07-02 12:42 [Bug c/66740] New: omp simd reduction miscompiles at -O3 with AVX (recent regression) tprince at computer dot org
` (2 preceding siblings ...)
2015-07-02 12:48 ` tprince at computer dot org
@ 2015-07-02 13:57 ` rguenth at gcc dot gnu.org
2015-07-10 23:25 ` tprince at computer dot org
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2015-07-02 13:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66740
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
Target| |x86_64-*-*
Component|c |tree-optimization
Target Milestone|--- |6.0
Summary|omp simd reduction |[6 Regression] omp simd
|miscompiles at -O3 with AVX |reduction miscompiles at
|(recent regression) |-O3 with AVX (recent
| |regression)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug tree-optimization/66740] [6 Regression] omp simd reduction miscompiles at -O3 with AVX (recent regression)
2015-07-02 12:42 [Bug c/66740] New: omp simd reduction miscompiles at -O3 with AVX (recent regression) tprince at computer dot org
` (3 preceding siblings ...)
2015-07-02 13:57 ` [Bug tree-optimization/66740] [6 Regression] " rguenth at gcc dot gnu.org
@ 2015-07-10 23:25 ` tprince at computer dot org
4 siblings, 0 replies; 6+ messages in thread
From: tprince at computer dot org @ 2015-07-10 23:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66740
--- Comment #4 from tprince at computer dot org ---
It optimizes with implicit simd reduction and gives correct result with option
-ffast-math in place of -fopenmp.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2015-07-10 23:25 UTC | newest]
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2015-07-02 12:42 [Bug c/66740] New: omp simd reduction miscompiles at -O3 with AVX (recent regression) tprince at computer dot org
2015-07-02 12:43 ` [Bug c/66740] " tprince at computer dot org
2015-07-02 12:46 ` tprince at computer dot org
2015-07-02 12:48 ` tprince at computer dot org
2015-07-02 13:57 ` [Bug tree-optimization/66740] [6 Regression] " rguenth at gcc dot gnu.org
2015-07-10 23:25 ` tprince at computer dot org
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