[PATCH] D14909: [X86][FMA] Optimize FNEG(FMUL) Patterns

[Sanjay Patel via llvm-commits]

spatel added a comment.

Thanks, Steve.

Can we assume default rounding for now, change the operand to X86::FNMSUB, remove the nsz check, and leave a 'TODO' comment to revisit this after rounding mode support is added? I think it would be better to have this transform be more general if we can.

Simon - is there a reason to prefer waiting for type legalization before doing the transform? I know that's how it's done in PerformFMACombine(), but it seems that the more common pattern is to check for known legal types for a particular opcode. This allows the transform to fire earlier?


Repository:
  rL LLVM

http://reviews.llvm.org/D14909