Re: [PATCH v1 2/2] x86_64: Add {u}int_fast defs ideal for x86_64

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Thu, Apr 14, 2022 at 5:24 PM Joseph Myers <joseph@codesourcery.com> wrote:
>
> On Sun, 10 Apr 2022, Noah Goldstein via Libc-alpha wrote:
>
> > {u}int_fast{16|32} should never use 64-bit types. 64-bit instructions
> > often use more code size (REX prefix) and a variety of instructions are
> > slower on many implementations (div, bswap, etc...).
>
> Apart from the other issues discussed with this patch, installed headers
> should not be specific to either x86_64 or 32-bit x86; such headers, where
> architecture-specific, should go in an x86/ sysdeps directory and contain
> appropriate conditionals within the header, so a single set of installed
> headers works with a multilibbed compiler.
>
> > +# include <sysdeps/generic/int-fast.h>
>
> And an installed header can't do that sort of thing, because only a single
> version of any such header gets installed.  If you want to include a
> generic file it has to have a different name, with both being installed
> (cf. bits/mman-*.h, for example).

Good info to have but the patches have been drop for the ABI concerns.
>
> --
> Joseph S. Myers
> joseph@codesourcery.com