[PATCH] D32729: LV: Don't vectorize with unknown loop counts on divergent targets

Matt Arsenault via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Jun 20 14:03:20 PDT 2017


arsenm added a comment.

In https://reviews.llvm.org/D32729#785871, @hfinkel wrote:

> In https://reviews.llvm.org/D32729#785795, @arsenm wrote:
>
> > ping
>
>
> I don't understand this patch. Unless there is both a vector and scalar loop, and I don't see how vectorizing the loop affects divergence between threads one way or the other. Do you really mean to prohibit vectorization when you have a dynamic trip count *and also* don't require a scalar loop? If so, you might look at https://reviews.llvm.org/D34373 which is related.


Yes, the point is to avoid the additional condition where both loops could execute


https://reviews.llvm.org/D32729





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