calls.c (expand_call): If TARGET is passed by reference and is readonly, write a CLOBBER.

	* calls.c (expand_call): If TARGET is passed by reference and
	is readonly, write a CLOBBER.

From-SVN: r32716

gcc/ChangeLog

+Thu Mar 23 17:10:48 2000  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
+
+	* calls.c (expand_call): If TARGET is passed by reference and
+	is readonly, write a CLOBBER.
+
 2000-03-23  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* builtins.c (expand_builtin): Handle bcmp.

gcc/calls.c

@@ -2776,6 +2776,14 @@ expand_call (exp, target, ignore)
       if (is_longjmp)
 	current_function_calls_longjmp = 1, sibcall_failure = 1;
 
+      /* If this function is returning into a memory location marked as
+	 readonly, it means it is initializing that location.  But we normally
+	 treat functions as not clobbering such locations, so we need to
+	 specify that this one does.  */
+      if (target != 0 && GET_CODE (target) == MEM
+	  && structure_value_addr != 0 && RTX_UNCHANGING_P (target))
+	emit_insn (gen_rtx_CLOBBER (VOIDmode, target));
+
       /* If value type not void, return an rtx for the value.  */
 
       /* If there are cleanups to be called, don't use a hard reg as target.