PR tree-optimization/53239
	* tree-vrp.c (get_value_range): Set VR of
	SSA_NAME_IS_DEFAULT_DEF of DECL_BY_REFERENCE RESULT_DECL
	to nonnull.

	* g++.dg/opt/vrp3.C: New test.
	* g++.dg/opt/vrp3-aux.cc: New file.
	* g++.dg/opt/vrp3.h: New file.

From-SVN: r187240