PR c++/79681
	* fold-const.c (make_bit_field_ref): If orig_inner is COMPONENT_REF,
	attempt to use its first operand as BIT_FIELD_REF base.

	* g++.dg/cpp1y/constexpr-79681-1.C: New test.
	* g++.dg/cpp1y/constexpr-79681-2.C: New test.

From-SVN: r245804