[PATCH] D36454: [X86] Changes to extract Horizontal addition operation for AVX-512.

Craig Topper via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Sep 5 22:45:17 PDT 2017


craig.topper added a comment.

I think we should try to combine based on the add only being used by the extract_vector_elt. Turn the add into a 128-bit add being fed by extract_subvectors. Similarly if we see an add only being used by an extract_subvector we can shrink that add too and push the extracts up. This type of transform feels more generally useful because it will allow us to narrow many more adds in this code. This will enable EVEX->VEX to use a smaller encoding. We can apply this to many other opcodes as well.

If we do this early enough we should be able to shrink the add before the horizontal add detection.


https://reviews.llvm.org/D36454





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