[PATCH] D46760: [InstCombine] Enhance narrowUDivURem.

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy added a comment.

Bixia - is it correct to say that the behavior we want here is that we narrow arithmetic operations from 64 bits to 32 bits, irrespective of how many extra zero extend instructions we need to add?  If yes, perhaps this isn't a good match for InstCombine and we should be looking at a specialized target-dependent transformation pass?  InstCombine is a "mini LLVM" in that many LLVM passes have a simpler "do no harm" variant implemented in InstCombine, so this won't be anything new design-wise.


Repository:
  rL LLVM

https://reviews.llvm.org/D46760