[PATCH vkd3d v3 16/17] vkd3d-shader/hlsl: Replace register offsets with index paths in input/output copies.

[Matteo Bruni]

On Wed, Jul 20, 2022 at 3:24 PM Francisco Casas <fcasas at codeweavers.com> wrote:
>
> Signed-off-by: Francisco Casas <fcasas at codeweavers.com>
> ---
>
> v3:
> * No changes.
>
> The recursive structure of prepend_input_var_copy() and
> append_output_var_copy() could be preserved creating additional
> loads to complete the paths. Otherwise we would be requiring
> passing whole paths as arguments.
>
> These additional loads should be handled by DCE.
>
> Still, matrix vectors are copied iteratively instead of recursively now,
> to avoid the boilerplate of creating new loads in this last step.
>
> Signed-off-by: Francisco Casas <fcasas at codeweavers.com>
> ---
>  libs/vkd3d-shader/hlsl_codegen.c | 188 +++++++++++++++++++------------
>  1 file changed, 116 insertions(+), 72 deletions(-)
>
> diff --git a/libs/vkd3d-shader/hlsl_codegen.c b/libs/vkd3d-shader/hlsl_codegen.c
> index 6437006b..7a245007 100644
> --- a/libs/vkd3d-shader/hlsl_codegen.c
> +++ b/libs/vkd3d-shader/hlsl_codegen.c
> @@ -239,59 +239,75 @@ static struct hlsl_ir_var *add_semantic_var(struct hlsl_ctx *ctx, struct hlsl_ir
>      return ext_var;
>  }
>
> -static void prepend_input_copy(struct hlsl_ctx *ctx, struct list *instrs, struct hlsl_ir_var *var,
> -        struct hlsl_type *type, unsigned int field_offset, unsigned int modifiers, const struct hlsl_semantic *semantic)
> +static void prepend_input_copy(struct hlsl_ctx *ctx, struct list *instrs, struct hlsl_ir_load *lhs,
> +        struct hlsl_type *type, unsigned int modifiers, const struct hlsl_semantic *semantic)

I haven't put a lot of thought into this, but it seems to me we could
pass a deref instead of a redundant load and be mostly set. Mostly
because we then need to add the instructions to the instruction list
in some other way (e.g. by passing an explicit list).