wgsl output doesn't use parenthesis for mixed operations, generating invalid code

[expenses]

See gfx-rs/wgpu#6857

I got this error in Chromium

Compilation log for [Invalid ShaderModule (unlabeled)]:
6 error(s) generated while compiling the shader:
:67:54 error: mixing '+' and '^' requires parenthesis
        var _S4 : u32 = _S3 + (((((_S2 << (u32(4)))) + u32(2738958700) ^ (_S2 + sum_1)) ^ (((_S2 >> (u32(5)))) + u32(3355524772))));

slang code: https://github.com/NVIDIAGameWorks/Falcor/blob/9dc819c162b2070335c65060436041690b7937f8/Source/Falcor/Utils/Math/HashUtils.slang#L62-L74

[aleino-nv]

I have a fix ready for this, but I'll spend some more time tomorrow creating more exhaustive tests for this type of issue.

[aleino-nv]

With the above fix, the following WGSL code is now generated for the mentioned blockCipherTEA function:

https://shader-playground.timjones.io/a6fbc241c06921e0e3b71c5dfd1ad03d

[expenses]

Hey @aleino-nv, great work! != still needs parensthesis though. For example this function generates invalid code: https://shader-playground.timjones.io/e873e27794407bee99368aa55b342abd

bool isValidHemisphereReflection(const ShadingData sd, const ShadingFrame sf, const float3 wiLocal, const float3 woLocal, const float3 wo)
{
    // Check that wi/wo are in the upper hemisphere around the shading normal.
    if (min(wiLocal.z, woLocal.z) < kMinCosTheta) return false;

    // Check that wi/wo are on the same geometric side.
    bool wiTop = sd.frontFacing; // The flag is computed dot(wi, faceN) >= 0.f.
    bool woTop = dot(wo, sd.faceN) >= 0.f;
    if (wiTop != woTop) return false;

#if FALCOR_BACKFACE_BLACK
    // Additionally check that we're on the same geometric side as the shading normal.
    bool shadingTop = dot(sf.N, sd.faceN) >= 0.f;
    if (wiTop != shadingTop) return false;
#endif

    return true;
}

https://github.com/NVIDIAGameWorks/Falcor/blob/eb540f6748774680ce0039aaf3ac9279266ec521/Source/Falcor/Scene/Material/ShadingUtils.slang#L155-L172

Same with >= and &:

localhost/:1 Error while parsing WGSL: :652:26 error: mixing '>=' and '&' requires parenthesis
    if(any((ray_1.mDir_0 >= _S52 & (ray_1.mOrigin_0 >= vec3<f32>((f32(_S54) - 0.5f))))))
                         ^^^^^^^^^

[aleino-nv]

@expenses Thanks for reporting this! I will re-open this issue and look at some more cases.