[PATCH] D81416: [LV][SLP] Interleave to expose ILP for small loops with scalar reductions.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D81416#2110070 <https://reviews.llvm.org/D81416#2110070>, @AaronLiu wrote:

> I think all the four testcases are related to this patch, and I prefer to keep the testcase in this patch. The four testcases all serve different purposes:
>
> - PhaseOrdering/interleave_LV_SLP.ll shows that with the option in this patch on, instructions were vectorized. But which vectorizer make it work? We cannot tell.
> - Vectorize/LoopVectorize.cpp tells us that LV cannot vectorize the code, but interleave the instructions to expose ILP.
> - SLPVectorizer/PowerPC/interleave_SLP.ll demonstrates that after interleaving by LV, then SLP captures the opportunities and vectorize the instructions.
> - The one you added in PhaseOrdering/interleave-vectorization.ll show that without this patch(equivalently with the option in this patch off), the same testcase both LV and SLP cannot vectorize the instructions.


This still isn't quite what I was hoping for. Can you just add "-interleave-small-loop-scalar-reduction=true" to the RUN lines of the file I added and update the CHECK lines using the script? I want this patch to show *the diff* in IR for the proposed code change. I can't easily tell what is changing by comparing 2 different files.


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