[clang] [C++23] [CLANG] Adding C++23 constexpr math functions: fmin and frexp. (PR #88978)

[Hubert Tong via cfe-commits]

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@@ -14638,6 +14649,8 @@ bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) {
     return true;
   }
 
+  case Builtin::BIfmin:
+  case Builtin::BIfminf:
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hubert-reinterpretcast wrote:

I think we'll be missing at least "pedantic" diagnostics if we don't restrict the `constexpr`-ness to C++23 and up. So we do need that restriction.

The interaction with `-fno-builtin[-*]` may need more discussion. At least the documentation for that option would need to be updated if the C++23 `constexpr` math would break with it.

https://github.com/llvm/llvm-project/pull/88978