skia2/resources/sksl/shared/SwizzleOpt.sksl

uniform half4 colorRed, colorGreen, testInputs;

half fn(half4 v) {
    // Add an un-inlinable construct to ensure that fn() remains a standalone function.
    for (int x=1; x<=2; ++x) {
        return v.x;
    }
}

half4 main(float2 coords) {
    half4 v = testInputs;

    v = v.rgba;
    v = v.rgb0.abgr;
    v = v.rgba.00ra;
    v = v.rgba.rrra.00ra.11ab;
    v = v.abga.gb11;
    v = v.abgr.abgr;
    v = half4(v.rrrr.bb, 1, 1);
    v = half4(v.ba.grgr);

    // The swizzle will not be optimized away to avoid eliminating fn().
    v = half3(fn(v), 123, 456).yyzz;
    v = half3(fn(v), half2(123, 456)).yyzz;

    // The swizzle will be optimized away because fn() can be reordered.
    v = half3(fn(v), 123, 456).yzzx;
    v = half3(fn(v), half2(123, 456)).yzzx;

    // The swizzle will not be optimized away to avoid duplicating fn().
    v = half3(fn(v), 123, 456).yxxz;
    v = half3(fn(v), half2(123, 456)).yxxz;

    // Swizzled constants.
    v = half4(1, 2, 3, 4).xxyz;

    // Swizzled uniforms mixed with constants.
    v = half4(1, colorRed.rgb).yzwx;
    v = half4(1, colorRed.rgb).yxzw;

    // Left-side swizzles.
    v.rgba = v;
    v.abgr = v;
    v.rgba.ra = v.gb;
    v.abgr.gba = v.aa1;

    return v == half4(1) ? colorGreen : colorRed;
}