@@ -1797,6 +1797,16 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
alter_subreg (curr_id->operand_loc[nop], false);
return true;
}
+ auto fp_subreg_can_be_simplified_after_reload_p = [] (machine_mode innermode,
+ poly_uint64 offset,
+ machine_mode mode) {
+ reload_completed = 1;
+ bool res = simplify_subreg_regno (FRAME_POINTER_REGNUM,
+ innermode,
+ offset, mode) >= 0;
+ reload_completed = 0;
+ return res;
+ };
/* Force a reload of the SUBREG_REG if this is a constant or PLUS or
if there may be a problem accessing OPERAND in the outer
mode. */
@@ -1809,6 +1819,12 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
>= hard_regno_nregs (hard_regno, mode))
&& simplify_subreg_regno (hard_regno, innermode,
SUBREG_BYTE (operand), mode) < 0
+ /* Exclude reloading of frame pointer in subreg if frame pointer can not
+ be simplified here only because the reload is not finished yet. */
+ && (hard_regno != FRAME_POINTER_REGNUM
+ || !fp_subreg_can_be_simplified_after_reload_p (innermode,
+ SUBREG_BYTE (operand),
+ mode))
/* Don't reload subreg for matching reload. It is actually
valid subreg in LRA. */
&& ! LRA_SUBREG_P (operand))
The following patch improves code for avr LRA port. More explanation for the patch can be found in the commit message. The patch was successfully bootstrapped and tested on x86-64, aarch64, and ppc64le. commit 4b8878fbf7b74ea5c3405c9f558df0517036f131 Author: Vladimir N. Makarov <vmakarov@redhat.com> Date: Thu Jul 20 14:34:26 2023 -0400 [LRA]: Exclude reloading of frame pointer in subreg for some cases LRA for avr port reloads frame pointer in subreg although we can just simplify the subreg. It results in generation of bad performance code. The following patch fixes this. gcc/ChangeLog: * lra-constraints.cc (simplify_operand_subreg): Check frame pointer simplification.