[PATCH] libcpp: Use [[likely]] conditionally

Christophe Lyon christophe.lyon.oss@gmail.com
Tue Nov 23 20:34:04 GMT 2021


On Tue, Nov 23, 2021 at 4:41 PM Jeff Law via Gcc-patches <
gcc-patches@gcc.gnu.org> wrote:

>
>
> On 11/23/2021 8:26 AM, Christophe LYON via Gcc-patches wrote:
> > Hi!
> >
> > On 23/11/2021 01:26, Jeff Law via Gcc-patches wrote:
> >>
> >>
> >> On 11/22/2021 10:22 AM, Marek Polacek via Gcc-patches wrote:
> >>> Let's hide [[likely]] behind a macro, to suppress warnings if the
> >>> compiler doesn't support it.
> >>>
> >>> Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
> >>>
> >>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> >>>
> >>>     PR preprocessor/103355
> >>>
> >>> libcpp/ChangeLog:
> >>>
> >>>     * lex.c: Use ATTR_LIKELY instead of [[likely]].
> >>>     * system.h (ATTR_LIKELY): Define.
> >> OK
> >> jeff
> >
> >
> > This patch breaks the build when the host compiler is gcc-4.8.5,
> > because __has_cpp_attribute is not defined.
> Sigh.  I'd like to move to a more recent prereq if we could.
>

I don't know why we have such an old dependency indeed.
I am not requesting it, I just happen to have an old enough host
compiler so that I can check/complain when we accidentally
break the dependency :-)

Christophe



>
>
> >
> > Is this small patch OK with a proper ChangeLog?
> Yes.  Sorry about the breakage.
> jeff
>
>
>


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