re PR tree-optimization/47190 (ICE: in function_and_variable_visibility, at ipa.c:934 with static weakref variable)

	PR tree-optimization/47190
	 * cgraphunit.c (process_common_attributes): New function.
        (process_function_and_variable_attributes): Use it.
	* gcc.dg/attr-weakref-3.c: New testcase.

From-SVN: r169288