https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96854
Bug ID: 96854
Summary: avx vectorizer breaks complex arithmetic
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: already5chosen at yahoo dot com
Target Milestone: ---
'-Ofast -mavx -march=ivybridge' miscompiles this simple loop:
double complex foo(double complex acc, const double complex *x, const double
complex* y, int N)
{
for (int c = 0; c < N; ++c)
acc -= x[c] * y[c];
return acc;
}
The bug appears to be triggered by -fassociative-math, but it could be a
trigger rather than the reason.
You can find a reproducer here:
https://github.com/already5chosen/others/tree/master/cholesky_solver/gcc-bug
I only tried with MSYS2 variant of gcc 10.2.0
