// particular, call Values can have a stack map in case the callee
// grows the stack, but not themselves be a safe-point.
func (lv *liveness) hasStackMap(v *ssa.Value) bool {
	if !v.Op.IsCall() {
		return false
	}
	// wbZero and wbCopy are write barriers and
	// deeply non-preemptible. They are unsafe points and
	// hence should not have liveness maps.