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

[Hubert Tong via llvm-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:

At the Clang C/C++ Language Workgroup call on 2024-05-15, it was agreed that `-fno-builtin[-*]` should remain capable of disabling built-in treatment even when that treatment would be required for conformance w.r.t. `constexpr` behaviour of functions shared with C.

For me, the first expectation for this PR (on that subject) is an update to the documentation of `-fno-builtin[-*]`.

@AaronBallman @ldionne, I am no sure how we want to handle this w.r.t. documenting the C++23 implementation status. Does it go in both the Clang documentation (for the functions shared with C) and the libc++ documentation (for the overloads added by C++)?

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