On Mon, Jul 08, 2019 at 01:27:25PM +0200, Richard Biener wrote: > On Sun, Jul 7, 2019 at 7:12 PM Segher Boessenkool > <seg...@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 <seg...@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.
