On Tue, Apr 30, 2024 at 9:58 AM Richard Biener
<richard.guent...@gmail.com> wrote:
>
> On Fri, Apr 26, 2024 at 11:45 AM Aldy Hernandez via Gcc <gcc@gcc.gnu.org> 
> wrote:
> >
> > Hi folks!
> >
> > In implementing prange (pointer ranges), I have found a 1.74% slowdown
> > in VRP, even without any code path actually using the code.  I have
> > tracked this down to irange::get_bitmask() being compiled differently
> > with and without the bare bones patch.  With the patch,
> > irange::get_bitmask() has a lot of code inlined into it, particularly
> > get_bitmask_from_range() and consequently the wide_int_storage code.
> >
> > I don't know whether this is expected behavior, and if it is, how to
> > mitigate it.  I have tried declaring get_bitmask_from_range() inline,
> > but that didn't help.  OTOH, using __attribute__((always_inline))
> > helps a bit, but not entirely.  What does help is inlining
> > irange::get_bitmask() entirely, but that seems like a big hammer.
>
> You can use -Winline to see why we don't inline an inline declared
> function.  I would guess the unit-growth limit kicks in?

Ah, will do.  Thanks.

>
> Did you check a release checking compiler?  That might still
> inline things.

Yes, we only measure performance with release builds.

Aldy

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