[libc-commits] [libc] [libc][NFC] Fix GCC volatile warning (PR #78509)

[Nick Desaulniers via libc-commits]

nickdesaulniers wrote:

> Without forcing re-evaluation, the compiler will optimize and only use the default rounding mode output of the conversion for all the rounding modes.

As in the compiler may do constant folding with a default rounding mode (rather than a rounding mode that may be changed during runtime)?

Regardless, could use comments in the source then to document _why_.

https://github.com/llvm/llvm-project/pull/78509