[PATCH] [InstCombine] Fold bitcasts into loads across PHINodes

[Philip Pfaffe]

I adopted Chandler's suggestion of combining the PHI instead of the Load and updated the patch accordingly. I also added a missing RUN line to the test case.

The idea here is to detect a PHI whose only user is a Noop CastInst and then fold the cast back through the phi if the phi only depends on loads and matching casts. This produces a new cast for an incoming load (which should be folded into the loop later on), and skips incoming casts.


http://reviews.llvm.org/D9500

Files:
  lib/Transforms/InstCombine/InstCombinePHI.cpp
  test/Transforms/InstCombine/fold-phi-cast-load.ll

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