[Bug middle-end/126625] hwint.cc reflect_hwi () should use __builtin_bitreverse64 if supported.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D126625

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Just note that not all supported compilers have to define __has_builtin mac=
ro,
so it needs to be guarded (like it already is e.g. in ira-color.cc).=