constant buffer packed values addressed erroneously

[albertodemichelis]

It look like if several constant buffer values get packed in a single "constant buffer register" the hlslcc addresses only the first value in the register

for example in the following shader the buffer is all packed in a single register ("cb[0]")

EDIT: the problem only occurs when 2 or more "variables" are accessed at once (by the D3D HLSL optimizer) using a swizzle like "cb[0].xy" (when the optimizer doesn't pack them in a swizzle it works fine)

---

INPUT

cbuffer RenderTargetParams {
int Width;
int Height;
float AspectRatio;
}

struct VS_model0_ZNORMAL_Input {
float4 ObjectPosition : POSITION;
float3 Normal : NORMAL;

};

struct VS_model0_GATHER_Output {
float4 PixelPosition : SV_Position;
};

VS_model0_GATHER_Output main(VS_model0_ZNORMAL_Input input)
{
VS_model0_GATHER_Output output = (VS_model0_GATHER_Output)0;
float2 _screenuvnormalized;

_screenuvnormalized = float2(input.ObjectPosition.x / Width, input.ObjectPosition.y / Height);
output.PixelPosition.xy = _screenuvnormalized;
output.PixelPosition.zw = float2(Width * 2, Height * 2);
return output;

}

---

ASM

// Buffer Definitions:
//
// cbuffer RenderTargetParams
// {
//
// int Width; // Offset: 0 Size: 4
// int Height; // Offset: 4 Size: 4
// float AspectRatio; // Offset: 8 Size: 4 [unused]
//
// }
//
//
// Resource Bindings:
//
// Name Type Format Dim Slot Elements
// ------------------------------ ---------- ------- ----------- ---- --------
// RenderTargetParams cbuffer NA NA 0 1
//
//
//
// Input signature:
//
// Name Index Mask Register SysValue Format Used
// -------------------- ----- ------ -------- -------- ------- ------
// POSITION 0 xyzw 0 NONE float xy
// NORMAL 0 xyz 1 NONE float
//
//
// Output signature:
//
// Name Index Mask Register SysValue Format Used
// -------------------- ----- ------ -------- -------- ------- ------
// SV_Position 0 xyzw 0 POS float xyzw
//
vs_5_0
dcl_globalFlags refactoringAllowed
dcl_constantbuffer cb0[1], immediateIndexed
dcl_input v0.xy
dcl_output_siv o0.xyzw, position
dcl_temps 1
itof r0.xy, cb0[0].xyxx
div o0.xy, v0.xyxx, r0.xyxx
ishl r0.xy, cb0[0].xyxx, l(1, 1, 0, 0)
itof o0.zw, r0.xxxy
ret

---

OUTPUT

version 430

extension GL_ARB_shader_bit_encoding : require

struct vec1 {
float x;
};
struct uvec1 {
uint x;
};
struct ivec1 {
int x;
};
out gl_PerVertex {
vec4 gl_Position;
float gl_PointSize;
float gl_ClipDistance[];};
subroutine void SubroutineType();
layout(location = 0) uniform struct RenderTargetParamsVS_Type {
int Width;
int Height;
float AspectRatio;
} RenderTargetParamsVS;
layout(location = 0) in vec4 dcl_Input0;
vec4 Input0;

undef Output0

define Output0 phase0_Output0

vec4 phase0_Output0;
vec4 Temp[1];
ivec4 Temp_int[1];
uvec4 Temp_uint[1];
void main()
{
Input0 = dcl_Input0;
Temp_int[0].xy = floatBitsToInt(vec4(RenderTargetParamsVS.Width).xy);
Output0.xy = (vec4(Input0.xyxx / intBitsToFloat(Temp_int[0]).xyxx)).xy;
Temp_int[0].xy = (RenderTargetParamsVS.Width << ivec4(0x1, 0x1, 0x0, 0x0)).xy;
Output0.zw = (vec4(Temp_int[0].xxxy).zw);
gl_Position = vec4(phase0_Output0);
return;
}

the correct result should be more like

Temp_int[0].xy = (vec4(RenderTargetParamsVS.Width,RenderTargetParamsVS.Height,0,0) << ivec4(0x1, 0x1, 0x0, 0x0)).xy;

and

Temp_int[0].xy = floatBitsToInt(vec4(RenderTargetParamsVS.Width,RenderTargetParamsVS.Height,0,0).xy);

thank you for you time
Alberto