[Bug ipa/115533] [12/13/14/15 regression] flac miscompiled with -O3 -march=znver2 -fipa-pta -fno-vect-cost-model

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115533

--- Comment #8 from Sam James <sjames at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #5)
> I wonder if it's the badly tested interaction between IPA opts and IPA PTA,
> I assume -O2 -ftree-vectorize instead of -O3 isn't enough to reproduce?
> 

It isn't, surprisingly. It was also really sensitive to vectorisation -- for a
while, novector on one loop was enough, but it stopped being after reduction.
We'll see..