[clang] [Clang] Add constexpr eval for cmath builtins (PR #194327)

[Joshua Cranmer via cfe-commits]

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@@ -717,6 +717,335 @@ static inline Floating abs(InterpState &S, const Floating &In) {
   return Output;
 }
 
+static bool interp__builtin_ceil(InterpState &S, CodePtr OpPC,
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jcranmer-intel wrote:

Small nit: you call this function `__builtin_ceil`, but it's handling 3 of the 5 roundToIntegral variants. Where are the other two? And why is the function implying it's only handling one of them?

https://github.com/llvm/llvm-project/pull/194327