c-common.h (STATEMENT_LIST_HAS_LABEL): New.

        * c-common.h (STATEMENT_LIST_HAS_LABEL): New.
        * c-semantics.c (add_stmt): Set it.
        * c-decl.c (finish_decl): Use it to create a new BIND_EXPR
        before instantiating a variable sized type.

From-SVN: r85849

gcc/ChangeLog

 2004-08-12  Richard Henderson  <rth@redhat.com>
 
+	* c-common.h (STATEMENT_LIST_HAS_LABEL): New.
+	* c-semantics.c (add_stmt): Set it.
+	* c-decl.c (finish_decl): Use it to create a new BIND_EXPR
+	before instantiating a variable sized type.
+
+2004-08-12  Richard Henderson  <rth@redhat.com>
+
 	* stor-layout.c (round_up, round_down): Move ...
 	* fold-const.c (round_up, round_down): ... here.  Use 
 	multiple_of_p to avoid any arithmetic at all.

gcc/c-common.h

@@ -35,7 +35,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
       STMT_IS_FULL_EXPR_P (in _STMT)
       STATEMENT_LIST_STMT_EXPR (in STATEMENT_LIST)
    2: unused
-   3: unused
+   3: STATEMENT_LIST_HAS_LABEL (in STATEMENT_LIST)
    4: unused
 */
 
@@ -708,6 +708,10 @@ extern void finish_file	(void);
 #define STATEMENT_LIST_STMT_EXPR(NODE) \
   TREE_LANG_FLAG_1 (STATEMENT_LIST_CHECK (NODE))
 
+/* Nonzero if a label has been added to the statement list.  */
+#define STATEMENT_LIST_HAS_LABEL(NODE) \
+  TREE_LANG_FLAG_3 (STATEMENT_LIST_CHECK (NODE))
+
 /* WHILE_STMT accessors. These give access to the condition of the
    while statement and the body of the while statement, respectively.  */
 #define WHILE_COND(NODE)        TREE_OPERAND (WHILE_STMT_CHECK (NODE), 0)

gcc/c-decl.c

@@ -3061,7 +3061,24 @@ finish_decl (tree decl, tree init, tree asmspec_tree)
 	    }
 
 	  if (TREE_CODE (decl) != FUNCTION_DECL)
-	    add_stmt (build_stmt (DECL_EXPR, decl));
+	    {
+	      /* If we're building a variable sized type, and we might be
+		 reachable other than via the top of the current binding
+		 level, then create a new BIND_EXPR so that we deallocate
+		 the object at the right time.  */
+	      /* Note that DECL_SIZE can be null due to errors.  */
+	      if (DECL_SIZE (decl)
+		  && !TREE_CONSTANT (DECL_SIZE (decl))
+		  && STATEMENT_LIST_HAS_LABEL (cur_stmt_list))
+		{
+		  tree bind;
+		  bind = build (BIND_EXPR, void_type_node, NULL, NULL, NULL);
+		  TREE_SIDE_EFFECTS (bind) = 1;
+		  add_stmt (bind);
+		  BIND_EXPR_BODY (bind) = push_stmt_list ();
+		}
+	      add_stmt (build_stmt (DECL_EXPR, decl));
+	    }
 	}
   
 

gcc/c-semantics.c

@@ -140,6 +140,9 @@ add_stmt (tree t)
       STMT_IS_FULL_EXPR_P (t) = stmts_are_full_exprs_p ();
     }
 
+  if (code == LABEL_EXPR || code == CASE_LABEL_EXPR)
+    STATEMENT_LIST_HAS_LABEL (cur_stmt_list) = 1;
+
   /* Add T to the statement-tree.  Non-side-effect statements need to be
      recorded during statement expressions.  */
   append_to_statement_list_force (t, &cur_stmt_list);

gcc/testsuite/gcc.c-torture/execute/20040811-1.c

+/* Ensure that we deallocate X when branching back before its
+   declaration.  */
+
+void *volatile p;
+                                                                                
+int
+main (void)
+{
+  int n = 0;
+ lab:;
+  int x[n % 1000 + 1];
+  x[0] = 1;
+  x[n % 1000] = 2;
+  p = x;
+  n++;
+  if (n < 1000000)
+    goto lab;
+  return 0;
+}