DXC internal compiler crash using following shader

[Nielsbishere]

Description
DXC crashes internally during pixel shader compilation. This shader used to work with a previous DXC version (I think it was v1.7.2308) but seems to be broken in latest.

Steps to Reproduce

struct VertexOut {
    float4 pos    : SV_POSITION;
    float2 uv    : TEXCOORD0;
};

#define M_PI 3.1415926535897
// assumes x>0
float erfc(float x) {
    return 2.0 * exp(-x * x) / (2.319 * x + sqrt(abs(4.0 + 1.52 * x * x)));
}
float Lambda(float cosTheta, float sigmaSq) {
    float v = cosTheta / sqrt(abs((1.0 - cosTheta * cosTheta) * (2.0 * sigmaSq)));
    return max(0.0, (exp(-v * v) - v * sqrt(abs(M_PI)) * erfc(v)) / (2.0 * v * sqrt(abs(M_PI))));
    //return (exp(-v * v)) / (2.0 * v * sqrt(M_PI)); // approximate, faster formula
}
            
float4 PS(VertexOut input): SV_TARGET0 {
    return float4(input.uv, Lambda(input.uv.x, input.uv.y), 1); //_tex0.Sample(_samplerLinear, input.uv);
}

dxc -E PS -T ps_6_3 crash.hlsl

Actual Behavior
Shouldn't crash. I think it's valid HLSL, but then again it's legacy code so I'm not sure what it actually does. If it's invalid code then it should give an error instead.

Environment

• DXC version: v1.8.2403
• Host Operating System: N/A

[llvm-beanz]

This is a different manifestation of #6410. We're working on getting out the low-risk quick fix in the 1.8.2403.1 release tracked as #6420. We haven't figured out the correct long-term fix, so this bug will persist in main for a short time while we work that out.