[libc-commits] [libc] [libc] Make FPUtils' rounding_mode.h functions constexpr. (PR #149167)

[via libc-commits]

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@@ -20,18 +21,26 @@ namespace fputil {
 // Using the following observation:
 //   1.0f + 2^-25 = 1.0f        for FE_TONEAREST, FE_DOWNWARD, FE_TOWARDZERO
 //                = 0x1.000002f for FE_UPWARD.
-LIBC_INLINE bool fenv_is_round_up() {
-  volatile float x = 0x1.0p-25f;
-  return (1.0f + x != 1.0f);
+LIBC_INLINE static constexpr bool fenv_is_round_up() {
+  if (cpp::is_constant_evaluated()) {
+    return false;
+  } else {
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overmighty wrote:

Nit: if `if constexpr` is not needed then the `else` after `return` should be removed as per the LLVM Coding Standards. Same for the other functions changed.

https://github.com/llvm/llvm-project/pull/149167