[PATCH] D14050: [X86][SSE] Shuffle blends with zero

[Simon Pilgrim via llvm-commits]

RKSimon added a comment.

I've been investigating general build vector support and the problem I'm finding is the BUILD_VECTOR node is usually lowered before the shuffle we're trying to match - preventing easy matching (the constant data has often disappeared inside a LOAD, INSERT_VECTOR_ELT or something else). It should be possible to create a helper function to do this (possibly just expanding getShuffleScalarElt) but its quite beyond the scope of what I had in mind for this patch.


Repository:
  rL LLVM

http://reviews.llvm.org/D14050