Re: [Qemu-devel] [PATCH 2/2] tcg: Add missing tcg_can_emit_vec_op check in tcg_gen_gvec_2s

[Peter Maydell]

On 17 February 2018 at 16:40, Richard Henderson
<richard.hender...@linaro.org> wrote:
> This lead to an assertion failure for 64-bit vector multiply,
> which is not available in the AVX instruction set.
>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> ---
>  tcg/tcg-op-gvec.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/tcg/tcg-op-gvec.c b/tcg/tcg-op-gvec.c
> index 29f9cf34b4..432e577c35 100644
> --- a/tcg/tcg-op-gvec.c
> +++ b/tcg/tcg-op-gvec.c
> @@ -979,12 +979,15 @@ void tcg_gen_gvec_2s(uint32_t dofs, uint32_t aofs, 
> uint32_t oprsz,
>
>      type = 0;
>      if (g->fniv) {
> -        if (TCG_TARGET_HAS_v256 && check_size_impl(oprsz, 32)) {
> +        if (TCG_TARGET_HAS_v256 && check_size_impl(oprsz, 32)
> +            && tcg_can_emit_vec_op(g->opc, TCG_TYPE_V256, g->vece)) {
>              type = TCG_TYPE_V256;
> -        } else if (TCG_TARGET_HAS_v128 && check_size_impl(oprsz, 16)) {
> +        } else if (TCG_TARGET_HAS_v128 && check_size_impl(oprsz, 16)
> +                   && tcg_can_emit_vec_op(g->opc, TCG_TYPE_V128, g->vece)) {
>              type = TCG_TYPE_V128;
>          } else if (TCG_TARGET_HAS_v64 && !g->prefer_i64
> -               && check_size_impl(oprsz, 8)) {
> +                   && check_size_impl(oprsz, 8)
> +                   && tcg_can_emit_vec_op(g->opc, TCG_TYPE_V64, g->vece)) {
>              type = TCG_TYPE_V64;
>          }
>      }

Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>

Incidentally, I notice that the condition checks
     (TCG_TARGET_HAS_v256 && check_size_impl(oprsz, 32)
      && tcg_can_emit_vec_op(g->opc, TCG_TYPE_V256, g->vece))

     (TCG_TARGET_HAS_v128 && check_size_impl(oprsz, 16)
      && tcg_can_emit_vec_op(g->opc, TCG_TYPE_V128, g->vece))

     (TCG_TARGET_HAS_v64 && check_size_impl(oprsz, 8)
      && tcg_can_emit_vec_op(g->opc, TCG_TYPE_V64, g->vece))

seem to be quite commonly used -- perhaps factoring these out
into suitably named functions would make the code more readable?

thanks
-- PMM