gcc/c-family/ChangeLog:

	PR middle-end/81824
	* c-attribs.c (handle_copy_attribute): New function.

gcc/cp/ChangeLog:

	PR middle-end/81824
	* pt.c (warn_spec_missing_attributes): Move code to attribs.c.
	Call decls_mismatched_attributes.

gcc/ChangeLog:

	PR middle-end/81824
	* attribs.c (has_attribute): New helper function.
	(decls_mismatched_attributes, maybe_diag_alias_attributes): Same.
	* attribs.h (decls_mismatched_attributes): Declare.
	* cgraphunit.c (handle_alias_pairs): Call maybe_diag_alias_attributes.
	(maybe_diag_incompatible_alias): Use OPT_Wattribute_alias_.
	* common.opt (-Wattribute-alias): Take an argument.
	(-Wno-attribute-alias): New option.
	* doc/extend.texi (Common Function Attributes): Document copy.
	(Common Variable Attributes): Same.
	* doc/invoke.texi (-Wmissing-attributes): Document enhancement.
	(-Wattribute-alias): Document new option argument.

gcc/testsuite/ChangeLog:

	PR middle-end/81824
	* gcc.dg/Wattribute-alias.c: New test.
	* gcc.dg/Wmissing-attributes.c: New test.
	* gcc.dg/attr-copy.c: New test.
	* gcc.dg/attr-copy-2.c: New test.
	* gcc.dg/attr-copy-3.c: New test.
	* gcc.dg/attr-copy-4.c: New test.

From-SVN: r265980