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.
