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

[Hubert Tong via cfe-commits]

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@@ -0,0 +1,59 @@
+// RUN: %clang_cc1 -x c++ -triple x86_64-unknown-unknown -std=c++23 \
+// RUN: -DWIN -emit-llvm -o - %s | FileCheck %s --check-prefixes=WIN
+
+// RUN: %clang_cc1 -x c++ -triple x86_64-unknown-unknown -std=c++23 \
+// RUN: -emit-llvm -o - %s | FileCheck %s --check-prefixes=LNX
+
+#ifdef WIN
+#define INFINITY ((float)(1e+300 * 1e+300))
+#define NAN      (-(float)(INFINITY * 0.0F))
+#else
+#define NAN (__builtin_nanf(""))
+#define INFINITY (__builtin_inff())
+#endif
+
+int func()
+{
+  int i;
+
+  // fmin
+  constexpr double f1 = __builtin_fmin(15.24, 1.3);
+  constexpr double f2 = __builtin_fmin(-0.0, +0.0);
+  constexpr double f3 = __builtin_fmin(+0.0, -0.0);
+  constexpr float f4 = __builtin_fminf(NAN, NAN);
+  constexpr float f5 = __builtin_fminf(NAN, -1);
+  constexpr float f6 = __builtin_fminf(-INFINITY, 0);
+  constexpr float f7 = __builtin_fminf(INFINITY, 0);
+  constexpr long double f8 = __builtin_fminl(123.456L, 789.012L);
+
+  // frexp
+  constexpr double f9 = __builtin_frexp(123.45, &i);
+  constexpr double f10 = __builtin_frexp(0.0, &i);
+  constexpr double f11 = __builtin_frexp(-0.0, &i);
+  constexpr double f12 = __builtin_frexpf(NAN, &i);
+  constexpr double f13 = __builtin_frexpf(-NAN, &i);
+  constexpr double f14 = __builtin_frexpf(INFINITY, &i);
----------------
hubert-reinterpretcast wrote:

Copy/paste errors?
```suggestion
  constexpr float f12 = __builtin_frexpf(NAN, &i);
  constexpr float f13 = __builtin_frexpf(-NAN, &i);
  constexpr float f14 = __builtin_frexpf(INFINITY, &i);
```

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