Re: [PATCH v12 0/3] MR450: vkd3d-shader/ir: Flatten structured control flow instructions.

[Henri Verbeet (＠hverbeet)]

> +        case VKD3DSIH_BRANCH:
> +        {
> +            const struct vkd3d_shader_src_param *src = ins->src, *merge;
> +
> +            if (ins->src_count > 2)
> +            {
> +                assert(ins->src_count == 3);
> +                shader_dump_instruction_flags(compiler, ins);
> +                vkd3d_string_buffer_printf(buffer, " ");
> +                shader_dump_src_param(compiler, &src[0]);
> +                assert(src[1].reg.idx_count == 2);
> +                shader_print_label_id(compiler, " ? ", src[1].reg.idx[0].offset);
> +                shader_print_label_id(compiler, " : ", src[1].reg.idx[1].offset);
> +                merge = &src[2];
> +            }
> +            else
> +            {
> +                assert(ins->src_count);
> +                assert(src[0].reg.idx_count == 1);
> +                shader_print_label_id(compiler, " ", src[0].reg.idx[0].offset);
> +                merge = (ins->src_count > 1) ? &src[1] : NULL;
> +            }
> +            if (merge)
> +            {
> +                assert(merge->reg.idx_count >= 1 && merge->reg.idx_count <= 2);
> +                shader_print_label_id(compiler, ", merge ", merge->reg.idx[0].offset);
> +                if (merge->reg.idx_count > 1)
> +                    shader_print_label_id(compiler, ", continue ", merge->reg.idx[1].offset);
> +            }
> +            break;
> +        }

Would it be terrible to output branch instructions like any other instruction? As it is, these would be the only non-DCL instructions that need special handling, and I'm not sure that something along the lines of "branch_nz r0.x, l0, l1, l2, l3" is really much worse than something like "branch r0.x ? l0 : l1, merge l2, continue l3".

Is it necessary to flatten everything in a single commit? Or could we e.g. first do IF/ELSE/ENDIF, then LOOP/ENDLOOP/BREAK/CONTINUE, SWITCH/ENDSWITCH/CASE/etc.?

Incidentally, still not a fan of assert() in library code.