[PATCH] D37236: [InstCombine] add insertelement + shuffle demanded element fold

[Sanjay Patel via Phabricator via llvm-commits]

spatel updated this revision to Diff 113319.
spatel added a comment.

Patch updated:
Use @craig.topper 's suggested change to keep recursing in SimplifyDemandedVectorElts before replacing an operand.

This is a small change that fixes the case that motivated me to look here in the first place. I added a test case that would have been caught by my initial patch in https://reviews.llvm.org/rL312172, so we don't lose it. Eventually, I think we should make a separate pass to better simplify based on vector demanded elements without further burdening instcombine.


https://reviews.llvm.org/D37236

Files:
  lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
  lib/Transforms/InstCombine/InstCombineVectorOps.cpp
  test/Transforms/InstCombine/X86/x86-pshufb.ll
  test/Transforms/InstCombine/vec_demanded_elts.ll

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