[PATCH vkd3d 04/17] vkd3d-shader/hlsl: Propagate constant loads in copy propagation.

[Giovanni Mascellani]

Hi,

On 01/12/21 17:55, Matteo Bruni wrote:
> IIRC this patch gets rid of unnecessary copies from an immediate to a
> temporary variable. I already forgot the details but I'm pretty sure
> that it did something...

I already replied privately, but for the sake of having a publicly 
archived reference, this patch converts this:

trace:hlsl_dump_function:    2:      float | 1.00000000e+00
trace:hlsl_dump_function:    3:      float | 2.00000000e+00
trace:hlsl_dump_function:    4:      float | 3.00000000e+00
trace:hlsl_dump_function:    5:      float | 4.00000000e+00
trace:hlsl_dump_function:    6:            | = (<constructor-0>.x @2)
trace:hlsl_dump_function:    7:            | = (<constructor-0>.y @3)
trace:hlsl_dump_function:    8:            | = (<constructor-0>.z @4)
trace:hlsl_dump_function:    9:            | = (<constructor-0>.w @5)
trace:hlsl_dump_function:   10:     float4 | <constructor-0>
trace:hlsl_dump_function:   11:            | return

to this:

trace:hlsl_dump_function:    2:     float4 | {1.00000000e+00 
2.00000000e+00 3.00000000e+00 4.00000000e+00 }
trace:hlsl_dump_function:    3:            | return

It is not something 1/17 can (or should) be able to do. There might be a 
better way to do this with more generality, but this is here right now, 
so I think it makes sense to have it in master.

Giovanni.