[PATCH] X86: sink splat-shuffle into block doing a shift.

[Nadav Rotem]

  + If
  +  /// this is the case, LLVM will try to sink shufflevectors implementing a
  +  /// splat before CodeGen to permit the better output.

  LGTM, except that I would omit the line above.  The shufflevector sinking is one example of a usage of this hook.

http://llvm-reviews.chandlerc.com/D2816