Re: [PATCH vkd3d v4 05/10] vkd3d-shader/hlsl: Add Gather methods with offset and tests.

[Matteo Bruni]

On Tue, Dec 21, 2021 at 2:04 PM Francisco Casas  wrote:
> diff --git a/libs/vkd3d-shader/hlsl_sm4.c b/libs/vkd3d-shader/hlsl_sm4.c
> index d55815f1..61247031 100644
> --- a/libs/vkd3d-shader/hlsl_sm4.c
> +++ b/libs/vkd3d-shader/hlsl_sm4.c
> @@ -1661,6 +1661,50 @@ static void write_sm4_loop(struct hlsl_ctx *ctx,
>      write_sm4_instruction(buffer, &instr);
>  }
> -
>
> +static void write_sm4_gather(struct hlsl_ctx *ctx, struct vkd3d_bytecode_buffer *buffer,
> -
>    const struct hlsl_type *resource_type, const struct hlsl_ir_node *dst,
> -
>    const struct hlsl_deref *resource, const struct hlsl_deref *sampler, const struct hlsl_ir_node *coords,
> -
>    unsigned int swizzle, const struct hlsl_ir_node *texel_offset)
>
> +{
> - struct sm4_instruction instr;
> - unsigned int writemask;
> -
> - memset(&instr, 0, sizeof(instr));
> -
> - /* TODO: possible optimization, if the offset ranges from -8 to 7, an VKD3D_SM4_OP_GATHER4 with
> - an aoffimmi modifier can be used. */
> - instr.opcode = texel_offset? VKD3D_SM5_OP_GATHER4_PO : VKD3D_SM4_OP_GATHER4;

Not just an optimization, since the _PO variant is SM5 which is
problematic if we're compiling for a 4.0 profile.

It's okay to have this as a (temporary) TODO though.