[PATCH] D69563: [LV] Strip wrap flags from vectorized reductions

Tue Oct 29 07:20:53 PDT 2019

dantrushin added a comment.

In D69563#1725269 <https://reviews.llvm.org/D69563#1725269>, @lebedev.ri wrote:

> I remember seeing similar patch for SLPVectorizer(?).
>  There the consensus was that the flags that are present on all instructions, can be preserved.
>  This isn't applicable here?

Reductions are special case, IMHO. As you can see, interleaving creates new vector IV {0,-,X}, which obviously wraps, 
even though original scalar  {-104,-,x} did not

So I believe we have bug here.
I need a fix for it so I had to create this review to get wheels rolling, because other means (asking on llvm-dev and filing PR) did not work ;-P

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D69563/new/

https://reviews.llvm.org/D69563