From 4b8878fbf7b74ea5c3405c9f558df0517036f131 Mon Sep 17 00:00:00 2001 From: "Vladimir N. Makarov" Date: Thu, 20 Jul 2023 14:34:26 -0400 Subject: [PATCH] [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. --- gcc/lra-constraints.cc | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc index 76a155e99c2..f3784cf5a5b 100644 --- a/gcc/lra-constraints.cc +++ b/gcc/lra-constraints.cc @@ -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))