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.
I contributed this through the PR a long time ago, but then I got
sidetracked. This patch wasn't enough to bring SH to a working state
with LRA, and I haven't been able to keep track of progress there, but
Oleg asked me to contribute it, so here it is. Regstrapped on
x86_64-linux-gnu. Ok to install?
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.
---
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 66a300bf268bd..910f3fba8f478 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);
--
Alexandre Oliva, happy hacker https://blog.lx.oliva.nom.br/
Free Software Activist FSFLA co-founder GNU Toolchain Engineer
Partially available for GNU toolchain professional services/consulting
