re PR middle-end/92384 (Empty class instances have different equal testing result among GCC versions)

	PR c++/92384
	* function.c (assign_parm_setup_block, assign_parm_setup_stack): Don't
	copy TYPE_EMPTY_P arguments from data->entry_parm to data->stack_parm
	slot.
	(assign_parms): For TREE_ADDRESSABLE parms with TYPE_EMPTY_P type
	force creation of a unique data.stack_parm slot.

	* g++.dg/torture/pr92384.C: New test.

From-SVN: r277962