Hi Shi-Hua:
> --- a/gcc/config/riscv/riscv.c
> +++ b/gcc/config/riscv/riscv.c
> @@ -1872,7 +1872,7 @@ riscv_rtx_costs (rtx x, machine_mode mode, int
> outer_code, int opno ATTRIBUTE_UN
> case MULT:
> if (float_mode_p)
> *total = tune_param->fp_mul[mode == DFmode];
> - else if (!TARGET_MUL)
> + else if (!TARGET_MUL && !TARGET_ZMMUL)
> /* Estimate the cost of a library call. */
> *total = COSTS_N_INSNS (speed ? 32 : 6);
> else if (GET_MODE_SIZE (mode) > UNITS_PER_WORD)
> @@ -4736,6 +4736,9 @@ riscv_option_override (void)
> if (flag_pic)
> g_switch_value = 0;
>
> + /* zmmul */
> + if (TARGET_ZMMUL && TARGET_MUL)
> + error ("can not use both the %<ZMMUL%> and the %<M%> extension");
My understanding is zmmul and M are not mutually exclusive, so we
don't need this check,
Otherwise it is LGTM, but I'm just surprised it's still 0.1 and not frozen yet.
[1] https://github.com/riscv/riscv-isa-manual/pull/648#issuecomment-842461775
