Re: [PATCH v2 09/12] target/arm: Optimize MVE VSHL, VSHR immediate forms

[Richard Henderson]

On 9/13/21 2:54 AM, Peter Maydell wrote:
> +static void do_gvec_shri_s(unsigned vece, uint32_t dofs, uint32_t aofs,
> +                           int64_t shift, uint32_t oprsz, uint32_t maxsz)
> +{
> +    /*
> +     * We get here with a negated shift count, and we must handle
> +     * shifts by the element size, which tcg_gen_gvec_sari() does not do.
> +     */
> +    shift = -shift;

You've already performed the negation in do_2shift_vec.

> +    if (shift == (8 << vece)) {
> +        shift--;
> +    }
> +    tcg_gen_gvec_sari(vece, dofs, aofs, shift, oprsz, maxsz);
...
> +    if (shift == (8 << vece)) {
> +        tcg_gen_gvec_dup_imm(vece, dofs, oprsz, maxsz, 0);
> +    } else {
> +        tcg_gen_gvec_shri(vece, dofs, aofs, shift, oprsz, maxsz);
> +    }


Perhaps worth placing these functions somewhere we can share code with NEON?  Tactical 
error, perhaps, open-coding these tests in trans_VSHR_S_2sh and trans_VSHR_U_2sh.

r~