Re: [PATCH v3 03/13] compiler.h: remove GCC < 3 __builtin_expect fallback

[Peter Maydell <peter.maydell@xxxxxxxxxx>]

On Thu, 10 Dec 2020 at 14:32, Philippe Mathieu-Daudé <philmd@xxxxxxxxxx> wrote:
>
> On 12/10/20 2:47 PM, marcandre.lureau@xxxxxxxxxx wrote:
> > From: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
> >
> > Since commit efc6c07 ("configure: Add a test for the minimum compiler
> > version"), QEMU explicitely depends on GCC >= 4.8.
> >
> > (clang >= 3.4 advertizes itself as GCC >= 4.2 compatible and supports
> > __builtin_expect too)
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>

> Shouldn't it becleaner to test in the configure script or Meson that
> likely() and unlikely() are not defined, and define them here
> unconditionally?

That sounds like way more infrastructure than we need if
just checking "is it already defined" is sufficient...

-- PMM