Re: Fix typo 586/686 in atomics/arch-x86.h

On Fri, Dec 19, 2025 at 4:04 PM Daniel Gustafsson <daniel@yesql.se> wrote:
> > I believe CI tests with -m32, so as long as we do that we should
> > probably make that work the way we think it does.
>
> It does, but will this affect that?  Does gcc change the CPU arch to 32bit era
> hardware when using -m32?  I was under the impression that it built code that
> can run in 32-bit mode on the underlying hardware unless a specific target arch
> was defined - but this is outside my wheelhouse so I might well be uninformed.

It's outside mine as well, but when I saw this thread I thought of
Thomas's experiment to use <stdatomic.h> and the need to verify code
generation on various platforms, so I see this patch as preventing
some head-scratching with that effort. With this patch applied on a
non-debug -m32 build I do see changes with bloaty:

    FILE SIZE        VM SIZE
 --------------  --------------
  +0.3% +6.27Ki  +0.3% +6.27Ki    .eh_frame
  -0.0%     -16  -0.0%     -16    .eh_frame_hdr
  -0.0%     -32  [ = ]       0    .symtab
  -0.0%     -47  [ = ]       0    .strtab
  -0.0%    -198  [ = ]       0    .debug_abbrev
  -0.1%    -512  [ = ]       0    .debug_rnglists
 -34.3% -3.20Ki  [ = ]       0    [Unmapped]
  -0.1% -3.63Ki  [ = ]       0    .debug_line
  -0.1% -7.06Ki  -0.1% -7.06Ki    .text
  -0.2% -8.44Ki  [ = ]       0    .debug_loclists
  -0.0% -8.70Ki  [ = ]       0    .debug_info
  -0.1% -25.5Ki  -0.0%    -824    TOTAL

--
John Naylor
Amazon Web Services