[PATCH] Lower FNEG ( FABS (x) ) -> FNABS (x) [X86 codegen] PR20578

[Elena Demikhovsky]

================
Comment at: lib/Target/X86/X86ISelLowering.cpp:12344
@@ +12343,3 @@
+  if (IsFABS)
+    for (SDNode *User : Op->uses())
+      if (User->getOpcode() == ISD::FNEG)
----------------
I think this check is not necessary because the graph always comes from bottom.

http://reviews.llvm.org/D5201