re PR debug/83157 (gcc.dg/guality/pr41616-1.c fail, inline instances refer to concrete instance as abstract origin)

2018-01-12  Richard Biener  <rguenther@suse.de>

	PR debug/83157
	* dwarf2out.c (gen_variable_die): Do not reset old_die for
	inline instance vars.

From-SVN: r256580