Make uitofp and sitofp defined on overflow.
IEEE 754 defines the expected result on overflow. As far as I know,
hardware implementations (of f16), and compiler-rt (__floatuntisf)
correctly return +-Inf on overflow. And I can't think of any useful
transform that would take advantage of overflow being undefined here.
Differential Revision: https://reviews.llvm.org/D47807
llvm-svn: 334777
diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp
index 218adb4..514a534 100644
--- a/llvm/lib/IR/ConstantFold.cpp
+++ b/llvm/lib/IR/ConstantFold.cpp
@@ -682,13 +682,8 @@
const APInt &api = CI->getValue();
APFloat apf(DestTy->getFltSemantics(),
APInt::getNullValue(DestTy->getPrimitiveSizeInBits()));
- if (APFloat::opOverflow &
- apf.convertFromAPInt(api, opc==Instruction::SIToFP,
- APFloat::rmNearestTiesToEven)) {
- // Undefined behavior invoked - the destination type can't represent
- // the input constant.
- return UndefValue::get(DestTy);
- }
+ apf.convertFromAPInt(api, opc==Instruction::SIToFP,
+ APFloat::rmNearestTiesToEven);
return ConstantFP::get(V->getContext(), apf);
}
return nullptr;