Incorrect GLSL logic about the reuse variables and countbits function

[xlincuts]

Hi,

I found 2 issues in the generated GLSL logic

The HLSL source:

cbuffer csInput_CB : register(b0)
{
    uint g_MaskDefault;
    uint g_MaskX;
    uint g_MaskY;
};

RWBuffer<uint> csOutput : register(u0);
// ------------------------------------------------------------------------------

void CalculateMask(inout uint mask, in uint index, in uint maskComponent)
{
    uint curBit = 1;
    mask = g_MaskDefault;

    [loop]
    for (uint i = 0; i < index; ++i)
    {
        [flatten]
        if ((index & 1) && (maskComponent & 1))
        {
            mask = curBit;
            break;
        }
        curBit <<= 1;
    }
}

// ------------------------------------------------------------------------------
[numthreads(1, 1, 1)]
void main(uint3 threadID : SV_DispatchThreadID)
{
    uint2 masks = 0;
    uint outputOffset = (threadID.x << 1);
    uint checkIndex = threadID.x + 1;

    CalculateMask(masks.x, checkIndex, g_MaskX);
    CalculateMask(masks.y, checkIndex, g_MaskY);

    uint count = countbits(masks.x) + countbits(masks.y);

    if (count > 0)
    {
        csOutput[outputOffset + 0] = masks.x;
        csOutput[outputOffset + 1] = masks.y;
    }
}

The generated GLSL source:

#version 430
#extension GL_ARB_shading_language_420pack : require

layout(location = 0) uniform 	uint g_MaskDefault;
uniform 	uint g_MaskX;
uniform 	uint g_MaskY;
writeonly layout(binding=0) uniform uimageBuffer csOutput;
ivec3 u_xlati0;
uint u_xlatu0;
uint u_xlatu1;
ivec3 u_xlati2;
uvec3 u_xlatu2;
bvec3 u_xlatb2;
uint u_xlatu3;
int u_xlati4;
int u_xlati5;
uint u_xlatu5;
bool u_xlatb5;
layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
void main()
{
    u_xlatu0 = gl_GlobalInvocationID.x + 1u;
    u_xlati2.x = int(u_xlatu0 & 1u);
    u_xlati2.yz = ivec2(csInput_CBCS.uvec2(g_MaskX, g_MaskY) & uvec2(1u, 1u));
    u_xlatb2.xyz = notEqual(u_xlati2.xyzz, ivec4(0, 0, 0, 0)).xyz;
    u_xlatb2.x = u_xlatb2.y && u_xlatb2.x; 
    u_xlatb2.y = u_xlatb2.z && u_xlatb2.x;Incorrect
    u_xlatu2.z = csInput_CBCS.g_MaskDefault;
    u_xlatu1 = uint(1u);
    for(uint u_xlatu_loop_1 = uint(0u) ; u_xlatu_loop_1<u_xlatu0 ; u_xlatu_loop_1++)
    {
        u_xlatu5 = (u_xlatb2.x) ? u_xlatu1 : u_xlatu2.z;
        u_xlatu2.z = u_xlatu5;
        u_xlati5 = int(u_xlatb2.x);
        if(u_xlati5 != 0) {break;}
        u_xlatu1 = u_xlatu1 << 1u;
    }
    u_xlatu2.x = csInput_CBCS.g_MaskDefault;
    u_xlatu1 = uint(1u);
    for(uint u_xlatu_loop_2 = uint(0u) ; u_xlatu_loop_2<u_xlatu0 ; u_xlatu_loop_2++)
    {
        u_xlatu5 = (u_xlatb2.y) ? u_xlatu1 : u_xlatu2.x;
        u_xlatu2.x = u_xlatu5;
        u_xlati5 = int(u_xlatb2.y);
        if(u_xlati5 != 0) {break;}
        u_xlatu1 = u_xlatu1 << 1u;
    }
    u_xlati0.xz = bitCount(ivec4(u_xlatu2.zzxz));
    u_xlati0.x = u_xlati0.z + u_xlati0.x;
    if(u_xlati0.x != 0) {
        u_xlati0.x = int(gl_GlobalInvocationID.x) << 1;
        imageStore(csOutput, u_xlati0.x, u_xlatu2.zzzz);
        u_xlati4 = int(gl_GlobalInvocationID.x) * 2 + 1;
        imageStore(csOutput, int(u_xlati4), u_xlatu2.xxxx);
    //ENDIF
    }
    return;
}

Issue1: Incorrect reuse variables

'u_xlatb2.y' will get an incorrect result, as 'u_xlatb2.x' in the previous step has been changed.
So the next logics which're using 'x_xlatb2.y', will get the error results

u_xlatu0 = gl_GlobalInvocationID.x + 1u; // u_xlatu0 --> checkIndex (in HLSL)
u_xlatb2.xyz = notEqual(u_xlati2.xyzz, ivec4(0, 0, 0, 0)).xyz; //  x --> (checkIndex&1), y --> (g_MaskX&1), z --> (g_MaskY&1)
u_xlatb2.x = u_xlatb2.y && u_xlatb2.x;  // u_xlatb2.x --> (checkIndex&1) && (g_MaskX&1)
u_xlatb2.y = u_xlatb2.z && u_xlatb2.x; // Error: u_xlatb2.y --> (checkIndex&1) && (g_MaskX&1) && (g_MaskY&1),
                                       // it should be (checkIndex&1) && (g_MaskY&1)

Issue2: countbits function convert

The bitCount argument is incorrect, when 'z' is 0 and 'x' greater 0, the 'u_xlati0' will get an incorrect result.

u_xlati0.xz = bitCount(ivec4(u_xlatu2.zzxz));

For the detail compilation information, please check Here