[PATCH] RISC-V: Checking 'm' extension when using RVV.

[Jan Beulich]

On 21.01.2025 16:23, Jiawei wrote:
> --- a/bfd/elfxx-riscv.c
> +++ b/bfd/elfxx-riscv.c
> @@ -2123,7 +2123,15 @@ riscv_parse_check_conflicts (riscv_parse_subset_t *rps)
>  	(_("`xtheadvector' is conflict with the `v' extension"));
>        no_conflict = false;
>      }
> -
> +  /* We might use a multiplication to calculate the scalable vector length at
> +     runtime.  Therefore, require the M extension.  */
> +  if (riscv_lookup_subset (rps->subset_list, "v", &subset)
> +      && !riscv_lookup_subset (rps->subset_list, "m", &subset))
> +    {
> +      rps->error_handler
> +	(_("Currently the 'v' implementation requires the 'm' extension"));
> +      no_conflict = false;
> +    }

Who or what is "we" in the comment? The impression I'm getting is that
you talk of other people's / project's code, which we shouldn't put
constraints on. Otherwise could you please point me (and possibly
others) at the multiplication code injected by binutils behind the
user's back?

Jan