Re: Defend against -ffast-math in meson builds

Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com> writes:
> But still, I'm not sure the code-level guard is enough for meson. I think we
> need to put a guard in meson.build for the "oddity" described in [1]:

> it compiles fine with CFLAGS="-ffast-math" CC="gcc" meson setup meson_build but
> produces issues during the regression tests.

> I just had a closer look and it looks like that the reason is that it's being
> added at link time:

> $ cat meson_build/build.ninja | grep LINK_ARGS | grep -c "ffast-math"
> 254

Oy. Surely that is a meson bug? AFAICS most of the effects of
-ffast-math should occur at compile time. Perhaps it also results
in linking a different version of libm, but that's not everything.
So just transposing it into link flags is not okay.

regards, tom lane