From b780f68e025b2cf5631183e199ebf672ea463af6 Mon Sep 17 00:00:00 2001 From: Jim Wilson Date: Sat, 8 Feb 2020 13:57:36 -0800 Subject: [PATCH] RISC-V: Improve caller-save code generation. Avoid paradoxical subregs when caller save. This reduces stack frame size due to smaller loads and stores, and more frequent rematerialization. PR target/93532 * config/riscv/riscv.h (HARD_REGNO_CALLER_SAVE_MODE): Define. --- gcc/ChangeLog | 5 +++++ gcc/config/riscv/riscv.h | 7 +++++++ 2 files changed, 12 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ed3aac49f1b..0ae8c5442a0 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2020-02-08 Jim Wilson + + PR target/93532 + * config/riscv/riscv.h (HARD_REGNO_CALLER_SAVE_MODE): Define. + 2020-02-08 Uroš Bizjak Jakub Jelinek diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h index 19438e28fe8..567c23380fe 100644 --- a/gcc/config/riscv/riscv.h +++ b/gcc/config/riscv/riscv.h @@ -268,6 +268,13 @@ along with GCC; see the file COPYING3. If not see 1, 1 \ } +/* Select a register mode required for caller save of hard regno REGNO. + Contrary to what is documented, the default is not the smallest suitable + mode but the largest suitable mode for the given (REGNO, NREGS) pair and + it quickly creates paradoxical subregs that can be problematic. */ +#define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \ + ((MODE) == VOIDmode ? choose_hard_reg_mode (REGNO, NREGS, NULL) : (MODE)) + /* Internal macros to classify an ISA register's type. */ #define GP_REG_FIRST 0 -- 2.30.2