On Fri, Jun 15, 2018 at 10:31:26AM -0600, Jeff Law wrote:
> On 06/14/2018 02:32 PM, David Malcolm wrote:
> > The idea is to later use these macros to mark the
> > if (dump_enabled_p ())
> > parts of the compiler as cold, in the hope of helping non-PGO builds
> > of gcc.
> >
> > I haven't measured it yet, though.
> >
> > gcc/ChangeLog:
> > * system.h (GCC_LIKELY, GCC_UNLIKELY): New macros, adapted from
> > libgfortran.h.
> ISTM if we're going to bother with this stuff that we should try to be
> consistent between glibc and gcc. Anything else seems like utter
> madness to me.
Do we really need these macros at all? We are already using
__builtin_expect directly in gcc/ subdirectory (with system.h providing
a dummy macro if not supported by the host compiler).
And I bet GCC developers are all familiar with __builtin_expect.
Jakub
