DXC Crash on Bad Shader

[mhurliman]

From forums question: https://forums.xboxlive.com/questions/121031/dxc-compiler-crash-on-invalid-compute-shader.html

Shader code is invalid - shouldn't compile successfully, but crashes DXC without providing an error message. Seems to be related to assigning one RWTexture2D global variable to another.

Command line: dxc /Tcs_6_0 /Emain shader.txt

shader.txt

[pow2clk]

Copying shader here for convenience:

#define MY_RS    "RootFlags(0),"  \
    "CBV(b0), " \
    "DescriptorTable(UAV(u0, numDescriptors = 3)) " 

// Each #kernel tells which function to compile; you can have many kernels
//#pragma kernel BlurShader
RWTexture2D<float4> _blurResult;

RWTexture2D<float4> _previousResult;

RWTexture2D<float4> _previousTarget;

float _blendFactor,_blurSize, _blurDirections, _blurQuality;

RWTexture2D<float4> blur(RWTexture2D<float4> tex, float2 uv, float2 stride)
{
    float Pi = 6.28318530718; // Pi*2

    float2 Radius = _blurSize / stride;

    float4 Color = tex[uv];

    // Blur calculations
    for (float d = 0.0; d < Pi; d += Pi / _blurDirections)
    {
        float2 angles = float2(cos(d), sin(d));

        for (float i = 1.0 / _blurQuality; i <= 1.0; i += 1.0 / _blurQuality)
        {
            Color.r += tex[uv + angles * Radius * i].r;
        }
    }

    float divisor = _blurQuality * _blurDirections - 15.0;
    if (divisor == 0)
    {
        divisor = 0.0001;
    }
    Color.r /= divisor;

    tex[uv] = Color;

    //return Color;
    return tex;
}

[RootSignature(MY_RS)]
[numthreads(8,8,1)]
void main(uint3 id : SV_DispatchThreadID)
{
    float x, y;
    _blurResult.GetDimensions(x, y);
    RWTexture2D<float4> filterFog = blur(_blurResult, id.xy, float2(x, y));

    _previousResult[id.xy] = lerp(_previousResult[id.xy], _previousTarget[id.xy], _blendFactor);
    _blurResult = filterFog;
}

[damyanp]

Repros on latest: https://godbolt.org/z/jehx1f56z