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

[via cfe-commits]

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@@ -199,6 +199,25 @@ static llvm::APSInt convertBoolVectorToInt(const Pointer &Val) {
   return Result;
 }
 
+static bool CheckFloatResult(InterpState &S, CodePtr OpPC,
+                             const APFloat &Result, APFloat::opStatus Status) {
+  if (S.inConstantContext())
+    return true;
+
+  // If any of the following exceptions were raised, the operation is not a
+  // constant expression.
+  if (Status & (APFloat::opInvalidOp | APFloat::opOverflow |
+                APFloat::opUnderflow | APFloat::opDivByZero)) {
+    if (!S.checkingPotentialConstantExpression()) {
+      const SourceInfo &Loc = S.Current->getSource(OpPC);
+      S.CCEDiag(Loc, diag::note_constexpr_float_arithmetic) << Result.isNaN();
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Serosh-commits wrote:

> Minor nit: CheckFloatResult could provide more specific diagnostics about which FP exception occurred. This can be deferred to a follow-up PR.

yeah sure i will add up a follow up pr for this thanks 

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