uniform half4 I, N;
uniform half4 colorGreen, colorRed;

half4 main(float2 xy) {
    // Ensure that constant-evaluation is safe even when the expression cannot be optimized.
    // The half() constructor is required to disambiguate from reflect(float, float).
    half expectedX = reflect(half(65504)*222*2, -65504);

    const half4 constI    = half4(1, -2, 3, -4);
    const half4 constN    = half4(-5, 6, -7, 8);

          expectedX    = half (-49);
    half2 expectedXY   = half2(-169, 202);
    half3 expectedXYZ  = half3(-379, 454, -529);
    half4 expectedXYZW = half4(-699, 838, -977, 1116);

    return (reflect(I.x,         N.x        ) == expectedX    &&
            reflect(I.xy,        N.xy       ) == expectedXY   &&
            reflect(I.xyz,       N.xyz      ) == expectedXYZ  &&
            reflect(I.xyzw,      N.xyzw     ) == expectedXYZW &&
            reflect(constI.x,    constN.x   ) == expectedX    &&
            reflect(constI.xy,   constN.xy  ) == expectedXY   &&
            reflect(constI.xyz,  constN.xyz ) == expectedXYZ  &&
            reflect(constI.xyzw, constN.xyzw) == expectedXYZW) ? colorGreen
                                                               : colorRed;
}