https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63844
Bug ID: 63844
Summary: open mp parallelization prevents vectorization
Product: gcc
Version: 4.9.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: andi-gcc at firstfloor dot org
#define N 10000000
int a[N], b[N], c[N];
main()
{
int i;
#pragma omp parallel num_threads(4)
for (i = 0; i < N; i++) {
a[i] = b[i] + c[i];
}
for (i = 0; i < N; i++) {
a[i] += b[i] + c[i];
}
}
compiled with gcc -O3 -fopenmp
The first loop gets parallelized by openmp, the second loop gets vectorized.
But why does the parallelized loop not get vectorized too?
