Thomas Schwinge <tschwi...@baylibre.com> writes: > Hi! > > On 2024-06-20T14:34:18+0100, Richard Sandiford <richard.sandif...@arm.com> > wrote: >> This patch adds a combine pass that runs late in the pipeline. >> [...] > > Nice! > >> The patch [...] disables the pass by default on i386, rs6000 >> and xtensa. > > Like here: > >> --- a/gcc/config/i386/i386-options.cc >> +++ b/gcc/config/i386/i386-options.cc >> @@ -1942,6 +1942,10 @@ ix86_override_options_after_change (void) >> flag_cunroll_grow_size = flag_peel_loops || optimize >= 3; >> } >> >> + /* Late combine tends to undo some of the effects of STV and RPAD, >> + by combining instructions back to their original form. */ >> + if (!OPTION_SET_P (flag_late_combine_instructions)) >> + flag_late_combine_instructions = 0; >> } > > ..., I think also here: > >> --- a/gcc/config/rs6000/rs6000.cc >> +++ b/gcc/config/rs6000/rs6000.cc >> @@ -4768,6 +4768,14 @@ rs6000_option_override_internal (bool global_init_p) >> targetm.expand_builtin_va_start = NULL; >> } >> >> + /* One of the late-combine passes runs after register allocation >> + and can match define_insn_and_splits that were previously used >> + only before register allocation. Some of those define_insn_and_splits >> + use gen_reg_rtx unconditionally. Disable late-combine by default >> + until the define_insn_and_splits are fixed. */ >> + if (!OPTION_SET_P (flag_late_combine_instructions)) >> + flag_late_combine_instructions = 0; >> + >> rs6000_override_options_after_change (); > > ..., this needs to be done in 'rs6000_override_options_after_change' > instead of 'rs6000_option_override_internal', to address the PRs under > discussion. I'm testing such a patch.
Oops! Sorry about that, and thanks for tracking it down. Richard
