PR debug/43166
	* cfgexpand.c (expand_debug_expr) <case VAR_DECL>: If mode is
	BLKmode, assert op0 is a MEM and just adjust its mode.

	* trans-common.c (build_common_decl): Also update DECL_MODE,
	and DECL_SIZE when encountering a larger common block and call
	layout_decl.

	* gfortran.dg/debug/pr43166.f: New test.

From-SVN: r157063