select min and max value

test.glsl

uint x;
uint y;

if (false) { // 46 cycles, 9 instrs.
x = min(ia,ib);
y = max(ia,ib);
}

if (false) { // 30 cycles, 15 instrs.
if (ia <= ib) {
x = ia;
y = ib;
} else {
x = ib;
y = ia;
}
}

if (true) { // 30 cycles, 14 instrs.
x = ib;
y = ia;
if (ia <= ib) {
x = ia;
y = ib;
}
}

if (true) { // 30 cycles, 15 instrs.
uvec2 iab = uvec2(ia,ib);
uvec2 tmp = (iab.x <= iab.y) ? iab.xy : iab.yx;
x = tmp.x;
y = tmp.y;
}