function logaddexp( x, y ) {
	return addon( x, y );
}
Computes the natural logarithm of `exp(x) + exp(y)`.

@private
@param {number} x - first number
@param {number} y - second number
@returns {number} natural logarithm of \\( \exp(x) + \exp(y) \\)

@example
var v = logaddexp( 90.0, 90.0 );
// returns ~90.6931

@example
var v = logaddexp( -20.0, 90.0 );
// returns 90.0

@example
var v = logaddexp( NaN, 1.0 );
// returns NaN

@example
var v = logaddexp( 0.0, -100.0 );
// returns ~3.7201e-44