[PATCH] D77635: [LV] Vectorize with FoldTail when Primary Induction is absent

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

I was also drafting a patch to implement this yesterday, and it was pretty much this! So I guess that's a good sign. :-)

> @SjoerdMeijer , test tail-folding-counting-down.ll introduced in D72324 <https://reviews.llvm.org/D72324> now fails, as it can be vectorized with fold-tail, but is not vectorized due to cost. What's the intention of this test and how should it be changed?

The purpose of this test was to catch a regression that we were seeing when tail-predication was rejected, but then incorrectly vectorisation also wasn't happening.
In this case, I think it is good to force vectorisation with a vectorisation vector of 4 or something along those lines. I was also modifying this test, but that will do for now, and then I will pick it up later.


Repository:
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  https://reviews.llvm.org/D77635/new/

https://reviews.llvm.org/D77635