I was thinking does it possible to using peephole2 to optimize this
case, but I realized their is several barrier, like stack tie and
note...so it seems hard to just leverage peephole2.
And the patch is LGTM, only a few minor coding format issues, but you
don't need to send new patch, I can fix those stuff when I push, and I
would strongly suggest you setup git-format-patch, <gcc-src>/contrib
has a clang format setting , that can release you from the boring
coding format issues.
# Copy to <gcc-src>/.clang-format, so that clang-format can found that
automatically.
$ cp contrib/clang-format .clang-format
> @@ -5747,6 +5748,80 @@ riscv_adjust_libcall_cfi_epilogue ()
> return dwarf;
> }
>
> +/* return true if popretz pattern can be matched.
> + set (reg 10 a0) (const_int 0)
> + use (reg 10 a0)
> + NOTE_INSN_EPILOGUE_BEG */
> +static rtx_insn *
> +riscv_zcmp_can_use_popretz(void)
Need space between function name and (void)
> +{
> + rtx_insn *insn = NULL, *use = NULL, *clear = NULL;
> +
> + /* sequence stack for NOTE_INSN_EPILOGUE_BEG*/
> + struct sequence_stack * outer_seq = get_current_sequence ()->next;
> + if (!outer_seq)
> + return NULL;
> + insn = outer_seq->first;
> + if(!insn || !NOTE_P (insn) || NOTE_KIND (insn) != NOTE_INSN_EPILOGUE_BEG)
> + return NULL;
> +
> + /* sequence stack for the insn before NOTE_INSN_EPILOGUE_BEG*/
> + outer_seq = outer_seq->next;
> + if (outer_seq)
> + insn = outer_seq->last;
> +
> + /* skip notes */
> + while (insn && NOTE_P (insn))
> + {
> + insn = PREV_INSN (insn);
> + }
> + use = insn;
> +
> + /* match use (reg 10 a0) */
> + if (use == NULL || !INSN_P (use)
> + || GET_CODE (PATTERN (use)) != USE
> + || !REG_P(XEXP(PATTERN (use), 0))
> + || REGNO(XEXP(PATTERN (use), 0)) != A0_REGNUM)
> + return NULL;
> +
> + /* match set (reg 10 a0) (const_int 0 [0]) */
> + clear = PREV_INSN (use);
> + if (clear != NULL && INSN_P (clear)
> + && GET_CODE (PATTERN (clear)) == SET
> + && REG_P (SET_DEST (PATTERN (clear)))
> + && REGNO (SET_DEST (PATTERN (clear))) == A0_REGNUM
> + && SET_SRC (PATTERN (clear)) == const0_rtx)
> + return clear;
> +
> + return NULL;
> +}
> +
> +static void
> +riscv_gen_multi_pop_insn(bool use_multi_pop_normal, unsigned mask,
> + unsigned multipop_size)
Same issue here, need space between argument and function name.
