public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [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] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 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
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).