re PR c++/83921 (GCC rejects constexpr initialization of empty aggregate.)

re PR c++/83921 (GCC rejects constexpr initialization of empty aggregate.)

/cp
2018-01-23  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/83921
	* decl.c (check_for_uninitialized_const_var): Not static; add
	bool and tsubst_flags_t parameters; adjust to be used both in
	constexpr context and not.
	* constexpr.c (potential_constant_expression_1): Use the above.
	* cp-tree.h (check_for_uninitialized_const_var): Declare.

/testsuite
2018-01-23  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/83921
	* g++.dg/cpp1y/constexpr-83921-1.C: New.
	* g++.dg/cpp1y/constexpr-83921-2.C: Likewise.
	* g++.dg/cpp1y/constexpr-83921-3.C: Likewise.
	* g++.dg/ext/stmtexpr20.C: Likewise.
	* g++.dg/ext/stmtexpr21.C: Likewise.

From-SVN: r257009