On 3/7/22 09:09, Francisco Casas wrote:
Hello,
March 4, 2022 10:01 PM, "Zebediah Figura (she/her)" zfigura@codeweavers.com wrote:
On 3/2/22 12:31, Francisco Casas wrote:
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@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.
As you know, if we have a HLSL_IR_STORE with a whole matrix in the rhs,
we have to split it in up to 4 stores, each one with a writemask that
matches the result of this type_default_writemask() here.
Well, yeah, but we should be using the result type in that case, i.e.
vectors rather than matrices.
The patch from Giovanni that implements this split_matrix_copies()
pass (which is many patches ahead), makes sure to do it with only vectors
in the rhs.
But currently, if I am not mistaken (I could be), a HLSL_IR_STORE with a
matrix in the rhs is producing a single MOV instruction for the first
register that the matrix uses. Which maybe could be problematic in sm4
with matrices with major size =1 and minor size <4.
Currently it's not producing anything, actually; we have a FIXME for
that case in write_sm[14]_instructions().
I added this default behavior thinking on those cases (if they could actually
happen), and maybe because I thought it could be useful in the future if for
some reason we wanted to implement split_matrix_copies() in other way, by
directly copying the store instructions.
But well, maybe I'll just do
if (!writemask && (type->type == HLSL_CLASS_SCALAR || type->type == HLSL_CLASS_VECTOR))
writemask = (1 << rhs->data_type->dimx) - 1;
or remove the patch altogether in the next version of the batch.
Best regards,
Francisco