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

[Sanjay Patel]

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

Without this check, all of the vector tests in the proposed test file fail because we process the FNEG first. I don't know why this is different between scalar and vector, but it is.

http://reviews.llvm.org/D5201