[PATCH] D82953: [ARM][MVE] Don't tail-fold float reductions

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

Hello. I agree with this, but I would suggest we take it further.

There are multiple forms of reductions that the vectorizer can produce. It's at least:
int add, int mul
float add, float mul
and, or, xor
int smin, smax, umin, umax
float min & max.

I think the ARMLowOverheadLoops will only currently handle integer add's. Considering how powerful the vectorizers handling of reductions is, and how easy (and expensive) it would be for the ARMLowOverheadLoops pass to get that wrong, I would suggest just disabling _all_ reductions at the moment.


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  https://reviews.llvm.org/D82953/new/

https://reviews.llvm.org/D82953