Jeff Law <l...@redhat.com> writes: > On 05/18/2015 12:13 PM, Richard Sandiford wrote: >> This patch adds a REG_NREGS macro that by the end of the series >> will simply be an rtx field access. The definition in this patch >> is just a placeholder (and so I haven't tried to avoid the double >> evaluation of the parameter). >> >> The diff has extra context because in most cases it makes it obvious >> that we really are looking at hard_regno_nregs[REGNO (x)][GET_MODE (x)] >> for some rtx x. There are a couple of sites where it's more indirect >> though. >> >> >> gcc/ >> * rtl.h (REG_NREGS): New macro >> * alias.c (record_set): Use it. >> * cfgcleanup.c (mark_effect): Likewise. >> * combine.c (likely_spilled_retval_1): Likewise. >> (likely_spilled_retval_p, can_change_dest_mode): Likewise. >> (move_deaths, distribute_notes): Likewise. >> * cselib.c (cselib_record_set): Likewise. >> * df-problems.c (df_simulate_one_insn_forwards): Likewise. >> * df-scan.c (df_mark_reg): Likewise. >> * dse.c (look_for_hardregs): Likewise. >> * dwarf2out.c (reg_loc_descriptor): Likewise. >> (multiple_reg_loc_descriptor): Likewise. >> * expr.c (write_complex_part, read_complex_part): Likewise. >> (emit_move_complex): Likewise. >> * haifa-sched.c (setup_ref_regs): Likewise. >> * ira-lives.c (mark_hard_reg_live): Likewise. >> * lra.c (lra_set_insn_recog_data): Likewise. >> * mode-switching.c (create_pre_exit): Likewise. >> * postreload.c (reload_combine_recognize_const_pattern): Likewise. >> (reload_combine_recognize_pattern): Likewise. >> (reload_combine_note_use, move2add_record_mode): Likewise. >> (reload_cse_move2add): Likewise. >> * reg-stack.c (subst_stack_regs_pat): Likewise. >> * regcprop.c (kill_value, copy_value): Likewise. >> (copyprop_hardreg_forward_1): Likewise. >> * regrename.c (verify_reg_in_set, scan_rtx_reg): Likewise. >> (build_def_use): Likewise. >> * sched-deps.c (mark_insn_reg_birth, mark_reg_death): Likewise. >> (deps_analyze_insn): Likewise. >> * sched-rgn.c (check_live_1, update_live_1): Likewise. >> * sel-sched.c (count_occurrences_equiv): Likewise. >> * valtrack.c (dead_debug_insert_temp): Likewise. >> > OK. > > Makes me wonder if we want to poison hard_regno_nregs in some way to > avoid folks re-introducing this stuff in the future... Your call if you > want to tackle that as a follow-up.
The problem is that many uses of hard_regno_nregs aren't about existing REGs. E.g. the register allocators need to know how many registers something would occupy before allocating it, so they (rightly) make heavy use of it with a calculated regno and/or mode. Agree that people will probably do things the old way out of habit. Maybe it's just something I should grep for occasionally... Thanks, Richard
