[llvm-commits] [llvm] r169452 - /llvm/trunk/lib/Analysis/ValueTracking.cpp

[Michael Ilseman]

Author: milseman
Date: Wed Dec  5 18:07:09 2012
New Revision: 169452

URL: http://llvm.org/viewvc/llvm-project?rev=169452&view=rev
Log:
Have CannotBeNegativeZero() be aware of the nsz fast-math flag

Modified:
    llvm/trunk/lib/Analysis/ValueTracking.cpp

Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=169452&r1=169451&r2=169452&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Wed Dec  5 18:07:09 2012
@@ -1312,7 +1312,12 @@
 
   const Operator *I = dyn_cast<Operator>(V);
   if (I == 0) return false;
-  
+
+  // Check if the nsz fast-math flag is set
+  if (const FPMathOperator *FPO = dyn_cast<FPMathOperator>(I))
+    if (FPO->hasNoSignedZeros())
+      return true;
+
   // (add x, 0.0) is guaranteed to return +0.0, not -0.0.
   if (I->getOpcode() == Instruction::FAdd &&
       isa<ConstantFP>(I->getOperand(1)) &&