expr.c (emit_block_move): Properly handle case where one of the block move…

expr.c (emit_block_move): Properly handle case where one of the block move arguments has a queued...

�
        * expr.c (emit_block_move): Properly handle case where one of the
        block move arguments has a queued increment or decrement.
        (clear_storage): Similarly.  Fix formatting goof.

From-SVN: r27822

gcc/expr.c

@@ -1710,6 +1710,37 @@ emit_block_move (x, y, size, align)
 	    }
 	}
 
+      /* X, Y, or SIZE may have been passed through protect_from_queue.
+
+	 It is unsafe to save the value generated by protect_from_queue
+	 and reuse it later.  Consider what happens if emit_queue is
+	 called before the return value from protect_from_queue is used.
+
+	 Expansion of the CALL_EXPR below will call emit_queue before
+	 we are finished emitting RTL for argument setup.  So if we are
+	 not careful we could get the wrong value for an argument.
+
+	 To avoid this problem we go ahead and emit code to copy X, Y &
+	 SIZE into new pseudos.  We can then place those new pseudos
+	 into an RTL_EXPR and use them later, even after a call to
+	 emit_queue. 
+
+	 Note this is not strictly needed for library calls since they
+	 do not call emit_queue before loading their arguments.  However,
+	 we may need to have library calls call emit_queue in the future
+	 since failing to do so could cause problems for targets which
+	 define SMALL_REGISTER_CLASSES and pass arguments in registers.  */
+      x = copy_to_mode_reg (Pmode, XEXP (x, 0));
+      y = copy_to_mode_reg (Pmode, XEXP (y, 0));
+
+#ifdef TARGET_MEM_FUNCTIONS
+      size = copy_to_mode_reg (TYPE_MODE (sizetype), size);
+#else
+      size = convert_to_mode (TYPE_MODE (integer_type_node), size,
+			      TREE_UNSIGNED (integer_type_node));
+      size = copy_to_reg (size);
+#endif
+
 #ifdef TARGET_MEM_FUNCTIONS
       /* It is incorrect to use the libcall calling conventions to call
 	 memcpy in this context.
@@ -1748,12 +1779,10 @@ emit_block_move (x, y, size, align)
 	 the last is a size_t byte count for the copy.  */
       arg_list
 	= build_tree_list (NULL_TREE,
-			    make_tree (build_pointer_type (void_type_node),
-				       XEXP (x, 0)));
+			   make_tree (build_pointer_type (void_type_node), x));
       TREE_CHAIN (arg_list)
 	= build_tree_list (NULL_TREE,
-			   make_tree (build_pointer_type (void_type_node),
-				      XEXP (y, 0)));
+			   make_tree (build_pointer_type (void_type_node), y));
       TREE_CHAIN (TREE_CHAIN (arg_list))
 	 = build_tree_list (NULL_TREE, make_tree (sizetype, size));
       TREE_CHAIN (TREE_CHAIN (TREE_CHAIN (arg_list))) = NULL_TREE;
@@ -1767,8 +1796,7 @@ emit_block_move (x, y, size, align)
       retval = expand_expr (call_expr, NULL_RTX, VOIDmode, 0);
 #else
       emit_library_call (bcopy_libfunc, 0,
-			 VOIDmode, 3, XEXP (y, 0), Pmode,
-			 XEXP (x, 0), Pmode,
+			 VOIDmode, 3, y, Pmode, x, Pmode
 			 convert_to_mode (TYPE_MODE (integer_type_node), size,
 					  TREE_UNSIGNED (integer_type_node)),
 			 TYPE_MODE (integer_type_node));
@@ -2444,69 +2472,97 @@ clear_storage (object, size, align)
 		}
 	    }
 
+	  /* OBJECT or SIZE may have been passed through protect_from_queue.
 
-#ifdef TARGET_MEM_FUNCTIONS
-      /* It is incorrect to use the libcall calling conventions to call
-	 memset in this context.
+	     It is unsafe to save the value generated by protect_from_queue
+	     and reuse it later.  Consider what happens if emit_queue is
+	     called before the return value from protect_from_queue is used.
 
-	 This could be a user call to memset and the user may wish to
-	 examine the return value from memset.
+	     Expansion of the CALL_EXPR below will call emit_queue before
+	     we are finished emitting RTL for argument setup.  So if we are
+	     not careful we could get the wrong value for an argument.
 
-	 For targets where libcalls and normal calls have different conventions
-	 for returning pointers, we could end up generating incorrect code. 
+	     To avoid this problem we go ahead and emit code to copy OBJECT
+	     and SIZE into new pseudos.  We can then place those new pseudos
+	     into an RTL_EXPR and use them later, even after a call to
+	     emit_queue.
 
-	 So instead of using a libcall sequence we build up a suitable
-	 CALL_EXPR and expand the call in the normal fashion.  */
-      if (fn == NULL_TREE)
-	{
-	  tree fntype;
+	     Note this is not strictly needed for library calls since they
+	     do not call emit_queue before loading their arguments.  However,
+	     we may need to have library calls call emit_queue in the future
+	     since failing to do so could cause problems for targets which
+	     define SMALL_REGISTER_CLASSES and pass arguments in registers.  */
+	  object = copy_to_mode_reg (Pmode, XEXP (object, 0));
 
-	  /* This was copied from except.c, I don't know if all this is
-	     necessary in this context or not.  */
-	  fn = get_identifier ("memset");
-	  push_obstacks_nochange ();
-	  end_temporary_allocation ();
-	  fntype = build_pointer_type (void_type_node);
-	  fntype = build_function_type (fntype, NULL_TREE);
-	  fn = build_decl (FUNCTION_DECL, fn, fntype);
-	  DECL_EXTERNAL (fn) = 1;
-	  TREE_PUBLIC (fn) = 1;
-	  DECL_ARTIFICIAL (fn) = 1;
-	  make_decl_rtl (fn, NULL_PTR, 1);
-	  assemble_external (fn);
-	  pop_obstacks ();
-	}
+#ifdef TARGET_MEM_FUNCTIONS
+	  size = copy_to_mode_reg (TYPE_MODE (sizetype), size);
+#else
+	  size = convert_to_mode (TYPE_MODE (integer_type_node), size,
+				  TREE_UNSIGNED (integer_type_node));
+	  size = copy_to_reg (size);
+#endif
 
-      /* We need to make an argument list for the function call. 
 
-	 memset has three arguments, the first is a void * addresses, the
-	 second a integer with the initialization value, the last is a size_t
-	 byte count for the copy.  */
-      arg_list
-	= build_tree_list (NULL_TREE,
-			    make_tree (build_pointer_type (void_type_node),
-				       XEXP (object, 0)));
-      TREE_CHAIN (arg_list)
-	= build_tree_list (NULL_TREE,
-			   make_tree (integer_type_node, const0_rtx));
-      TREE_CHAIN (TREE_CHAIN (arg_list))
-	 = build_tree_list (NULL_TREE, make_tree (sizetype, size));
-      TREE_CHAIN (TREE_CHAIN (TREE_CHAIN (arg_list))) = NULL_TREE;
+#ifdef TARGET_MEM_FUNCTIONS
+	  /* It is incorrect to use the libcall calling conventions to call
+	     memset in this context.
 
-      /* Now we have to build up the CALL_EXPR itself.  */
-      call_expr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (fn)), fn);
-      call_expr = build (CALL_EXPR, TREE_TYPE (TREE_TYPE (fn)),
-			 call_expr, arg_list, NULL_TREE);
-      TREE_SIDE_EFFECTS (call_expr) = 1;
+	     This could be a user call to memset and the user may wish to
+	     examine the return value from memset.
 
-      retval = expand_expr (call_expr, NULL_RTX, VOIDmode, 0);
+	     For targets where libcalls and normal calls have different
+	     conventions for returning pointers, we could end up generating
+	      incorrect code. 
+
+	     So instead of using a libcall sequence we build up a suitable
+	     CALL_EXPR and expand the call in the normal fashion.  */
+	  if (fn == NULL_TREE)
+	    {
+	      tree fntype;
+
+	      /* This was copied from except.c, I don't know if all this is
+		 necessary in this context or not.  */
+	      fn = get_identifier ("memset");
+	      push_obstacks_nochange ();
+	      end_temporary_allocation ();
+	      fntype = build_pointer_type (void_type_node);
+	      fntype = build_function_type (fntype, NULL_TREE);
+	      fn = build_decl (FUNCTION_DECL, fn, fntype);
+	      DECL_EXTERNAL (fn) = 1;
+	      TREE_PUBLIC (fn) = 1;
+	      DECL_ARTIFICIAL (fn) = 1;
+	      make_decl_rtl (fn, NULL_PTR, 1);
+	      assemble_external (fn);
+	      pop_obstacks ();
+	    }
+
+	  /* We need to make an argument list for the function call. 
+
+	     memset has three arguments, the first is a void * addresses, the
+	     second a integer with the initialization value, the last is a
+	     size_t byte count for the copy.  */
+	  arg_list
+	    = build_tree_list (NULL_TREE,
+			       make_tree (build_pointer_type (void_type_node),
+					  object));
+	  TREE_CHAIN (arg_list)
+	    = build_tree_list (NULL_TREE,
+			        make_tree (integer_type_node, const0_rtx));
+	  TREE_CHAIN (TREE_CHAIN (arg_list))
+	    = build_tree_list (NULL_TREE, make_tree (sizetype, size));
+	  TREE_CHAIN (TREE_CHAIN (TREE_CHAIN (arg_list))) = NULL_TREE;
+
+	  /* Now we have to build up the CALL_EXPR itself.  */
+	  call_expr = build1 (ADDR_EXPR,
+			      build_pointer_type (TREE_TYPE (fn)), fn);
+	  call_expr = build (CALL_EXPR, TREE_TYPE (TREE_TYPE (fn)),
+			     call_expr, arg_list, NULL_TREE);
+	  TREE_SIDE_EFFECTS (call_expr) = 1;
+
+	  retval = expand_expr (call_expr, NULL_RTX, VOIDmode, 0);
 #else
 	  emit_library_call (bzero_libfunc, 0,
-			     VOIDmode, 2,
-			     XEXP (object, 0), Pmode,	
-			     convert_to_mode
-			     (TYPE_MODE (integer_type_node), size,
-			      TREE_UNSIGNED (integer_type_node)),
+			     VOIDmode, 2, object, Pmode, size
 			     TYPE_MODE (integer_type_node));
 #endif
 	}