https://gcc.gnu.org/g:04bd6f2a933dbffcf769f39dcacb973436b1ebb3
commit 04bd6f2a933dbffcf769f39dcacb973436b1ebb3 Author: Alexandre Oliva <[email protected]> Date: Wed Dec 17 02:44:32 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);
