gimple.c (walk_gimple_op): Do not request a pure rvalue on the RHS if the LHS is of a non-renamable type.

	* gimple.c (walk_gimple_op) <GIMPLE_ASSIGN>: Do not request a pure
	rvalue on the RHS if the LHS is of a non-renamable type.
	* tree-ssa-ccp.c (maybe_fold_offset_to_component_ref): Fold result.
ada/
	* gcc-interface/ada-tree.h (TYPE_BY_REFERENCE_P): Delete.
	(DECL_CONST_ADDRESS_P): New macro.
	(SET_DECL_ORIGINAL_FIELD_TO_FIELD): Likewise.
	(SAME_FIELD_P): Likewise.
	* gcc-interface/decl.c (constructor_address_p): New static function.
	(gnat_to_gnu_entity) <object>: Set DECL_CONST_ADDRESS_P according to
	the return value of above function.
	(gnat_to_gnu_entity) <E_Record_Type>: Force BLKmode for all types
	passed by reference.
	<E_Record_Subtype>: Likewise.
	Set TREE_ADDRESSABLE on the type if it passed by reference.
	(make_packable_type): Use SET_DECL_ORIGINAL_FIELD_TO_FIELD.
	(create_field_decl_from): Likewise.
	(substitute_in_type): Likewise.
	(purpose_member_field): Use SAME_FIELD_P.
	* gcc-interface/misc.c (must_pass_by_ref): Test TREE_ADDRESSABLE.
	* gcc-interface/trans.c (lvalue_required_p): Add ADDRESS_OF_CONSTANT
	parameter and adjust recursive calls.
	<N_Explicit_Dereference>: New case.
	<N_Object_Declaration>: Return 1 if the object is of a class-wide type.
	Adjust calls to lvalue_required_p.  Do not return the initializer of a
	DECL_CONST_ADDRESS_P constant if an lvalue is required for it.
	(call_to_gnu): Delay issuing error message for a misaligned actual and
	avoid the associated back-end assertion.  Test TREE_ADDRESSABLE.
	(gnat_gimplify_expr) <ADDR_EXPR>: Handle non-static constructors.
	* gcc-interface/utils.c (make_dummy_type): Set TREE_ADDRESSABLE if the
	type is passed by reference.
	(convert) <CONSTRUCTOR>: Convert in-place in more cases.
	* gcc-interface/utils2.c (build_cond_expr): Drop TYPE_BY_REFERENCE_P.
	(build_simple_component_ref): Use SAME_FIELD_P.

From-SVN: r158254