function registerConditionsToGroup(conditions) {
			for (let i = 0; i < conditions.length; ++i) {
				const condition = conditions[i];

				if (condition.group) {
					let group = groupMap.get(condition.group);

					if (!group) {
						group = [];
						groupMap.set(condition.group, group);
					}
					group.push(condition);
				}
			}
		}
Registers given conditions to the group the condition belongs to.
@param {LoopConditionInfo[]} conditions A loop condition info to
     register.
@returns {void}