[PATCH vkd3d v3 2/8] vkd3d-shader/hlsl: Add default writemask for matrix stores.

[Matteo Bruni]

On Mon, Mar 7, 2022 at 6:33 PM Zebediah Figura <zfigura at codeweavers.com> wrote:
>
> On 3/7/22 09:09, Francisco Casas wrote:
> > Hello,
> >
> > March 4, 2022 10:01 PM, "Zebediah Figura (she/her)" <zfigura at codeweavers.com> wrote:
> >
> >> On 3/2/22 12:31, Francisco Casas wrote:
> >>
> >>> Signed-off-by: Francisco Casas <fcasas at codeweavers.com>
> >>> ---
> >>> v3:
> >>> - This patch is new.
> >>> - While we don't use the default writemask for matrices (yet),
> >>> I think it is good for consistency, since we are getting rid
> >>> of the type_is_single_reg() function.
> >>> Signed-off-by: Francisco Casas <fcasas at codeweavers.com>
> >>> ---
> >>> libs/vkd3d-shader/hlsl.c | 12 ++++++++----
> >>> 1 file changed, 8 insertions(+), 4 deletions(-)
> >>> diff --git a/libs/vkd3d-shader/hlsl.c b/libs/vkd3d-shader/hlsl.c
> >>> index 00a374b4..5152aec4 100644
> >>> --- a/libs/vkd3d-shader/hlsl.c
> >>> +++ b/libs/vkd3d-shader/hlsl.c
> >>> @@ -527,9 +527,13 @@ struct hlsl_ir_var *hlsl_new_synthetic_var(struct hlsl_ctx *ctx, const char
> >>> *nam
> >>> return var;
> >>> }
> >>>> -static bool type_is_single_reg(const struct hlsl_type *type)
> >>> +static unsigned int type_default_writemask(const struct hlsl_type *type)
> >>> - return type->type == HLSL_CLASS_SCALAR || type->type == HLSL_CLASS_VECTOR;
> >>> + if (type->type == HLSL_CLASS_MATRIX && hlsl_type_is_row_major(type))
> >>> + return (1 << type->dimy) - 1;
> >>
> >> I don't understand the logic here. A nonzero writemask should encompass the whole type, which this
> >> does not. Why do we need this?
> >>
> >
> > Well, I am not totally sure this patch is actually necessary, I just
> > thought it could be a good default behavior since we are getting rid of
> > hlsl_is_single_reg(), but maybe I am overthinking...
>
> FWIW, I don't know that that instance of type_is_single_reg()
> necessarily needs to go away. Although given 1/8, we could certainly say
> that a zero writemask always means the whole variable, and let
> hlsl_reg_from_deref() deal with that even for scalar and vector types.

I'd move in that direction too (shorter term, at least).