Propagate Undef in llvm.cos Intrinsic

Summary:
The llvm cos intrinsic currently does not propagate undef's. This change
transforms cos(undef) to null value or 0.

There are 2 test cases added as well.

Patch by Anna Thomas!

Reviewers: sanjoy

Subscribers: majnemer, llvm-commits

Differential Revision: http://reviews.llvm.org/D18863

llvm-svn: 265825

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 017d897def7..d87a0800262 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1443,6 +1443,11 @@ Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID, Type *Ty,
                                  ArrayRef<Constant *> Operands,
                                  const TargetLibraryInfo *TLI) {
   if (Operands.size() == 1) {
+    if (isa<UndefValue>(Operands[0])) {
+      // cosine(arg) is between -1 and 1. cosine(invalid arg) is NaN
+      if (IntrinsicID == Intrinsic::cos)
+        return Constant::getNullValue(Ty);
+    }
     if (ConstantFP *Op = dyn_cast<ConstantFP>(Operands[0])) {
       if (IntrinsicID == Intrinsic::convert_to_fp16) {
         APFloat Val(Op->getValueAPF());