diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index e9ec6db069c..694c31e1f96 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -245,7 +245,6 @@ bool llvm::canConstantFoldCallTo(Function *F) {
   const std::string &Name = F->getName();
 
   switch (F->getIntrinsicID()) {
-  case Intrinsic::isnan: return true;
   case Intrinsic::isunordered: return true;
   default: break;
   }
@@ -274,8 +273,6 @@ Constant *llvm::ConstantFoldCall(Function *F,
   if (Operands.size() == 1) {
     if (ConstantFP *Op = dyn_cast<ConstantFP>(Operands[0])) {
       double V = Op->getValue();
-      if (Name == "llvm.isnan")
-        return ConstantBool::get(isnan(V));
       else if (Name == "sin")
         return ConstantFP::get(Ty, sin(V));
       else if (Name == "cos")