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Fix some minor issues folding undef, PR2052 

llvm-svn: 47314
This commit is contained in:
Chris Lattner 2008-02-19 06:22:12 +00:00
parent 0fe6bce9ce
commit b4c6cc9587
1 changed files with 3 additions and 1 deletions
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4
llvm/lib/VMCore/ConstantFold.cpp
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@ -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);
}