================
@@ -768,6 +768,59 @@ void InitializeOpenCLFeatureTestMacros(const TargetInfo
&TI,
Builder.defineMacro("__opencl_c_int64");
}
+std::string ConstructFixedPointLiteral(llvm::APFixedPoint Val,
+ llvm::StringRef Suffix) {
+ if (Val.isSigned() && Val == llvm::APFixedPoint::getMin(Val.getSemantics()))
{
+ // When representing the min value of a signed fixed point type in source
+ // code, we cannot simply write `-<lowest value>`. For example, the min
+ // value of a `short _Fract` cannot be written as `-1.0hr`. This is because
+ // the parser will read this (and really any negative numerical literal) as
+ // a UnaryOperator that owns a FixedPointLiteral with a positive value
+ // rather than just a FixedPointLiteral with a negative value. Compiling
+ // `-1.0hr` results in an overflow to the maximal value of that fixed point
+ // type. The correct way to represent a signed min value is to instead
split
+ // it into two halves, like `(-0.5hr-0.5hr)` which is what the standard
+ // defines SFRACT_MIN as.
+ std::string Literal;
+ std::string HalfStr = ConstructFixedPointLiteral(Val.shr(1), Suffix);
+ Literal.push_back('(');
+ Literal += HalfStr;
----------------
MaskRay wrote:
Returning `SmallString` and using `Twine` to concatenate strings is slightly
more efficient.
https://github.com/llvm/llvm-project/pull/81207
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