[Mesa-dev] [PATCH] ac/nir: fix potential issues when scanning flat_shaded_mask

[Marek Olšák]

On Tue, Mar 6, 2018 at 10:58 AM, Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
> As far as I understand, this might overflow and shifted by one
> if for example, gl_PrimitiveID is used with flat generic varyings.
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>  src/amd/common/ac_nir_to_llvm.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
> index ea51c3a54a..d4fdb8e8f4 100644
> --- a/src/amd/common/ac_nir_to_llvm.c
> +++ b/src/amd/common/ac_nir_to_llvm.c
> @@ -5545,6 +5545,7 @@ handle_fs_inputs(struct radv_shader_context *ctx,
>         nir_foreach_variable(variable, &nir->inputs)
>                 handle_fs_input_decl(ctx, variable);
>
> +       uint64_t flat_shaded_mask = 0;
>         unsigned index = 0;
>
>         if (ctx->shader_info->info.ps.uses_input_attachments ||
> @@ -5564,8 +5565,8 @@ handle_fs_inputs(struct radv_shader_context *ctx,
>                         interp_fs_input(ctx, index, interp_param, ctx->abi.prim_mask,
>                                         inputs);
>
> -                       if (!interp_param)
> -                               ctx->shader_info->fs.flat_shaded_mask |= 1u << index;
> +                       if (i >= VARYING_SLOT_VAR0 && !interp_param)
> +                               flat_shaded_mask |= 1u << i;

1ull

Marek

>                         ++index;
>                 } else if (i == VARYING_SLOT_POS) {
>                         for(int i = 0; i < 3; ++i)
> @@ -5575,7 +5576,9 @@ handle_fs_inputs(struct radv_shader_context *ctx,
>                                                   ctx->abi.frag_pos[3]);
>                 }
>         }
> +
>         ctx->shader_info->fs.num_interp = index;
> +       ctx->shader_info->fs.flat_shaded_mask = flat_shaded_mask >> VARYING_SLOT_VAR0;
>         ctx->shader_info->fs.input_mask = ctx->input_mask >> VARYING_SLOT_VAR0;
>
>         if (ctx->shader_info->info.needs_multiview_view_index)
> --
> 2.16.2
>
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