Re: [PATCH 0/1] MR74: vkd3d-shader/hlsl: Support dot() for SM1.

[Francisco Casas (＠fcasas)]

Francisco Casas (@fcasas) commented about libs/vkd3d-shader/hlsl.y:
>  if (!(args[1] = add_implicit_conversion(ctx, instrs, arg2, common_type, loc)))
>      return NULL;
>
> - if (ctx->profile->major_version < 4 && dim == 2)
> - {
> -
>    struct hlsl_ir_constant *zero;
> -
> -
>    if (!(zero = hlsl_new_float_constant(ctx, 0.0f, loc)))
> -
>        return NULL;
> -
> -
>    if (!(args[2] = add_implicit_conversion(ctx, instrs, &zero->node, common_type, loc)))
> -
>        return NULL;
> - }
> -

I don't think it is a good idea to keep the zero constant as a hidden third parameter of `HLSL_OP2_DOT` during the whole compilation.

Others may disagree, but I think it may be better to introduce it in a new compilation pass in `hlsl_emit_bytecode()` inside this block:

```c
    if (profile->major_version < 4)
    {
        transform_ir(ctx, lower_division, body, NULL);
        transform_ir(ctx, lower_sqrt, body, NULL);
    }
```