On Mon, 14 Nov 2022 at 17:29, jiawei <jia...@iscas.ac.cn> wrote:
>
> Skip add insn generate if the adjust size equal to zero.
>
> gcc/ChangeLog:
>
> * config/riscv/riscv.cc (riscv_expand_epilogue):
> New if control segement.
>
> ---
> gcc/config/riscv/riscv.cc | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> index 02a01ca0b7c..af138db7545 100644
> --- a/gcc/config/riscv/riscv.cc
> +++ b/gcc/config/riscv/riscv.cc
> @@ -5186,24 +5186,26 @@ riscv_expand_epilogue (int style)
> }
>
> /* Get an rtx for STEP1 that we can add to BASE. */
> - rtx adjust = GEN_INT (step1.to_constant ());
> - if (!SMALL_OPERAND (step1.to_constant ()))
> + if (step1.to_constant () != 0){
> + rtx adjust = GEN_INT (step1.to_constant ());
> + if (!SMALL_OPERAND (step1.to_constant ()))
Please take a look at the recent improvements for the add<mode>3
expander (recently submitted as
https://patchwork.ozlabs.org/project/gcc/patch/20221109230718.3240479-1-philipp.toms...@vrull.eu/).
Maybe you also want to use the test for the addi_operand(...) instead
of SMALL_OPERAND?
> {
> riscv_emit_move (RISCV_PROLOGUE_TEMP (Pmode), adjust);
> adjust = RISCV_PROLOGUE_TEMP (Pmode);
> }
>
> - insn = emit_insn (
> + insn = emit_insn (
> gen_add3_insn (stack_pointer_rtx, stack_pointer_rtx, adjust));
>
> - rtx dwarf = NULL_RTX;
> - rtx cfa_adjust_rtx = gen_rtx_PLUS (Pmode, stack_pointer_rtx,
> + rtx dwarf = NULL_RTX;
> + rtx cfa_adjust_rtx = gen_rtx_PLUS (Pmode, stack_pointer_rtx,
> GEN_INT (step2));
>
> - dwarf = alloc_reg_note (REG_CFA_DEF_CFA, cfa_adjust_rtx, dwarf);
> - RTX_FRAME_RELATED_P (insn) = 1;
> + dwarf = alloc_reg_note (REG_CFA_DEF_CFA, cfa_adjust_rtx, dwarf);
> + RTX_FRAME_RELATED_P (insn) = 1;
>
> - REG_NOTES (insn) = dwarf;
> + REG_NOTES (insn) = dwarf;
> + }
> }
> else if (frame_pointer_needed)
> {
> --
> 2.25.1
>
