[libcxx-commits] [clang] [libcxx] [Clang] Allow __builtin_fma/fmaf/fmal to be used in a constant expression (PR #158048)

[Hubert Tong via libcxx-commits]

hubert-reinterpretcast wrote:

> The way I read the intent is that `FENV_ROUND` applies the behavior of the rounding mode to all known operations and restores the dynamic rounding mode for all unknown function calls, with standard library calls being considered to be a known operation when they are not macro-replaced.

Perhaps that is how you read the intent; however, the wording is clear that standard library calls are only subject to `FENV_ROUND` behaviour when they _are_ macro-replaced (by macros defined by the C library headers).

https://github.com/llvm/llvm-project/pull/158048