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

[Steve Canon via llvm-commits]

scanon added inline comments.

================
Comment at: lib/Target/X86/X86ISelLowering.cpp:26157
@@ -26141,3 +26156,3 @@
   // instruction to include the extra negation.
   if (Arg.hasOneUse()) {
     switch (Arg.getOpcode()) {
----------------
0 - a*b gets the sign of zero wrong if a or b is exactly zero; the result should be -0, but +0 is returned instead in default rounding.  So this should be protected by no signed zeros.


Repository:
  rL LLVM

http://reviews.llvm.org/D14909