Fix some minor issues folding undef, PR2052

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47314 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-02-19 06:22:12 +00:00
parent 50b2ca4c73
commit 46acf85b97

View File

@ -175,7 +175,9 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
if (isa<UndefValue>(V)) {
// zext(undef) = 0, because the top bits will be zero.
// sext(undef) = 0, because the top bits will all be the same.
if (opc == Instruction::ZExt || opc == Instruction::SExt)
// [us]itofp(undef) = 0, because the result value is bounded.
if (opc == Instruction::ZExt || opc == Instruction::SExt ||
opc == Instruction::UIToFP || opc == Instruction::SIToFP)
return Constant::getNullValue(DestTy);
return UndefValue::get(DestTy);
}