if (z.left === SENTINEL) {
y = z;
// x's delta is no longer influenced by z's delta
x.delta += z.delta;
if (x.delta < Constants.MIN_SAFE_DELTA || x.delta > Constants.MAX_SAFE_DELTA) {
T.requestNormalizeDelta = true;
}
x.end += z.delta;
} else if (z.right === SENTINEL) {
x = z.left;