From: Segher Boessenkool <segher@kernel.crashing.org>
To: Richard Biener <richard.guenther@gmail.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] subreg: Add -fsplit-wide-types-early (PR88233)
Date: Mon, 08 Jul 2019 17:28:00 -0000 [thread overview]
Message-ID: <20190708172055.GF30355@gate.crashing.org> (raw)
In-Reply-To: <CAFiYyc0UkTZSG392dYPM7vEytMvB4Gm6aHVsP2qm0OkRtC_YaQ@mail.gmail.com>
On Mon, Jul 08, 2019 at 01:27:25PM +0200, Richard Biener wrote:
> On Sun, Jul 7, 2019 at 7:12 PM Segher Boessenkool
> <segher@kernel.crashing.org> wrote:
> >
> > Currently the second lower-subreg pass is run right before RA. This
> > is much too late to be very useful. At least for targets that do not
> > have RTL patterns for operations on multi-register modes it is a lot
> > better to split patterns earlier, before combine and all related
> > passes.
> >
> > This adds an option -fsplit-wide-types-early that does that, and
> > enables it by default for rs6000.
>
> Do you by chance have a (target specific) testcase you can add?
I haven't yet figured out how to do a not terribly fragile test for this.
Hrm, maybe the thing in the PR with -mcpu=power8 will do. I'll work on
that.
> The docs should mention that the new option doesn't have any effect
> unless -fsplit-wide-types is enabled.
Yeah I'll make that more explicit. Thanks,
Segher
> > 2019-07-07 Segher Boessenkool <segher@kernel.crashing.org>
> >
> > PR rtl-optimization/88233
> > * common.opt (fsplit-wide-types-early): New option.
> > * common/config/rs6000/rs6000-common.c
> > (rs6000_option_optimization_table): Add OPT_fsplit_wide_types_early for
> > OPT_LEVELS_ALL.
> > * doc/invoke.texi (Optimization Options): Add -fsplit-wide-types-early.
> > * lower-subreg.c (pass_lower_subreg2::gate): Add test for
> > flag_split_wide_types_early.
> > (pass_data_lower_subreg3): New.
> > (pass_lower_subreg3): New.
> > (make_pass_lower_subreg3): New.
> > * passes.def (pass_lower_subreg2): Move after the loop passes.
> > (pass_lower_subreg3): New, inserted where pass_lower_subreg2 was.
> > * tree-pass.h (make_pass_lower_subreg2): Move up, to its new place in
> > the pass pipeline; its previous place is taken by ...
> > (make_pass_lower_subreg3): ... this.
next prev parent reply other threads:[~2019-07-08 17:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-07 18:45 Segher Boessenkool
2019-07-08 11:28 ` Richard Biener
2019-07-08 17:28 ` Segher Boessenkool [this message]
2019-07-08 17:43 ` Segher Boessenkool
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