PR ada/29025

	* trans.c (gnat_gimplify_expr) <ADDR_EXPR>: When taking the address
	of a SAVE_EXPR, just make the operand addressable/not-readonly and
	let the common gimplifier code make and propagate a temporary copy.
	(call_to_gnu): Clarify the use of SAVE_EXPR for not addressable
	out/in-out actuals and defer setting the addressable/readonly bits
	to the gimplifier.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@116929 138bc75d-0d04-0410-961f-82ee72b054a4

gcc/ada/ChangeLog

@@ -1,3 +1,13 @@
+2006-09-13  Olivier Hainque  <[email protected]>
+
+	PR ada/29025
+	* trans.c (gnat_gimplify_expr) <ADDR_EXPR>: When taking the address
+	of a SAVE_EXPR, just make the operand addressable/not-readonly and
+	let the common gimplifier code make and propagate a temporary copy.
+	(call_to_gnu): Clarify the use of SAVE_EXPR for not addressable
+	out/in-out actuals and defer setting the addressable/readonly bits
+	to the gimplifier.
+
 2006-09-13  Eric Botcazou  <[email protected]>
 
 	PR ada/28591

gcc/ada/trans.c

@@ -1775,18 +1775,12 @@ call_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p, tree gnu_target)
 		       && (TYPE_JUSTIFIED_MODULAR_P (gnu_name_type)))
 		gnu_name = convert (gnu_name_type, gnu_name);
 
+	      /* Make a SAVE_EXPR to both properly account for potential side
+		 effects and handle the creation of a temporary copy.  Special
+		 code in gnat_gimplify_expr ensures that the same temporary is
+		 used as the actual and copied back after the call.  */
 	      gnu_actual = save_expr (gnu_name);
 
-	      /* Since we're going to take the address of the SAVE_EXPR, we
-		 don't want it to be marked as unchanging. So set
-		 TREE_ADDRESSABLE.  */
-	      gnu_temp = skip_simple_arithmetic (gnu_actual);
-	      if (TREE_CODE (gnu_temp) == SAVE_EXPR)
-		{
-		  TREE_ADDRESSABLE (gnu_temp) = 1;
-		  TREE_READONLY (gnu_temp) = 0;
-		}
-
 	      /* Set up to move the copy back to the original.  */
 	      gnu_temp = build_binary_op (MODIFY_EXPR, NULL_TREE,
 					  gnu_copy, gnu_actual);
@@ -4697,6 +4691,19 @@ gnat_gimplify_expr (tree *expr_p, tree *pre_p, tree *post_p ATTRIBUTE_UNUSED)
 	  return GS_ALL_DONE;
 	}
 
+      /* If we are taking the address of a SAVE_EXPR, we are typically
+	 processing a misaligned argument to be passed by reference in a
+	 procedure call.  We just mark the operand as addressable + not
+	 readonly here and let the common gimplifier code perform the
+	 temporary creation, initialization, and "instantiation" in place of
+	 the SAVE_EXPR in further operands, in particular in the copy back
+	 code inserted after the call.  */
+      else if (TREE_CODE (op) == SAVE_EXPR)
+	{
+	  TREE_ADDRESSABLE (op) = 1;
+	  TREE_READONLY (op) = 0;
+	}
+
       /* Otherwise, if we are taking the address of something that is neither
 	 reference, declaration, or constant, make a variable for the operand
 	 here and then take its address.  If we don't do it this way, we may