https://gcc.gnu.org/g:af1f68b4e365caa06603598ec6b5b491fc00b40b
commit r16-6263-gaf1f68b4e365caa06603598ec6b5b491fc00b40b Author: Alexandre Oliva <[email protected]> Date: Fri Dec 19 04:57:05 2025 -0300 [lra] take scratch as implicit unused output reloads [PR55212] When trying to convert the SH port to use LRA, the first issue I hit was the need for dealing with former scratch registers at places we didn't need to on other ports, treating them like unused output reloads instead of rejecting them. for gcc/ChangeLog PR target/55212 * lra-constraints.cc (match_reload): Treat former scratch regs as implicit unused output reloads. (process_alt_operands): Likewise. (curr_insn_transform): Likewise. Diff: --- gcc/lra-constraints.cc | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc index 66a300bf268b..910f3fba8f47 100644 --- a/gcc/lra-constraints.cc +++ b/gcc/lra-constraints.cc @@ -1243,7 +1243,9 @@ match_reload (signed char out, signed char *ins, signed char *outs, return; /* See a comment for the input operand above. */ narrow_reload_pseudo_class (out_rtx, goal_class); - if (find_reg_note (curr_insn, REG_UNUSED, out_rtx) == NULL_RTX) + if (find_reg_note (curr_insn, REG_UNUSED, out_rtx) == NULL_RTX + && !ira_former_scratch_p (REGNO (SUBREG_P (out_rtx) + ? SUBREG_REG (out_rtx) : out_rtx))) { reg = SUBREG_P (out_rtx) ? SUBREG_REG (out_rtx) : out_rtx; start_sequence (); @@ -3002,7 +3004,8 @@ process_alt_operands (int only_alternative) objects with a REG_UNUSED note. */ if ((curr_static_id->operand[nop].type != OP_IN && no_output_reloads_p - && ! find_reg_note (curr_insn, REG_UNUSED, op)) + && ! find_reg_note (curr_insn, REG_UNUSED, op) + && ! scratch_p) || (curr_static_id->operand[nop].type != OP_OUT && no_input_reloads_p && ! const_to_mem) || (this_alternative_matches >= 0 @@ -3012,7 +3015,8 @@ process_alt_operands (int only_alternative) [this_alternative_matches].type != OP_IN) && ! find_reg_note (curr_insn, REG_UNUSED, no_subreg_reg_operand - [this_alternative_matches]))))) + [this_alternative_matches]) + && ! scratch_p)))) { if (lra_dump_file != NULL) fprintf @@ -4856,7 +4860,8 @@ curr_insn_transform (bool check_only_p) if (type != OP_IN && find_reg_note (curr_insn, REG_UNUSED, old) == NULL_RTX /* OLD can be an equivalent constant here. */ - && !CONSTANT_P (old)) + && !CONSTANT_P (old) + && !ira_former_scratch_p (REGNO (old))) { start_sequence (); lra_emit_move (type == OP_INOUT ? copy_rtx (old) : old, new_reg);
