Re: [PATCH v3 0/3] MR598: vkd3d-shader/ir: Lower monolithic switches to selection ladders.

[Conor McCarthy (＠cmccarthy)]

Conor McCarthy (@cmccarthy) commented about libs/vkd3d-shader/ir.c:
> -
>                goto fail;
> -
>        }
> -
>        else
>        {
>            if (!vsir_instruction_init_with_params(parser, &instructions[ins_count], &ins->location, VKD3DSIH_LABEL, 0, 1))
>                goto fail;
>            vsir_src_param_init_label(&instructions[ins_count].src[0], ++block_count);
>            ++ins_count;
> -
> -
>            if_label = block_count;
>        }
>    }
>
> }
> -
>
> /* Second subpass: creating new blocks might have broken
> -
> * references in PHI instructions, so we use the block map to fix

Do validation failures occur without this? AFAIK it's still valid to have a `phi` incoming from the original `switch` block. If block `1` contained the `switch`, block `5` is a switch case, and the conditional branch to `5` could instead branch to a new label `11`, we can still have incomings from `1` and `5`. If control flowed through `5` it gets the second value, otherwise it get the first.