re PR c++/38880 (g++.dg/init/const7.C XFAILed)

        PR c++/38880
        * varasm.c (initializer_constant_valid_p) [PLUS_EXPR]: Check
        narrowing_initializer_constant_valid_p.
        (narrowing_initializer_constant_valid_p): Don't return
        null_pointer_node for adding a pointer to itself.

From-SVN: r144395

gcc/ChangeLog

+2009-02-23  Jason Merrill  <jason@redhat.com>
+
+	PR c++/38880
+	* varasm.c (initializer_constant_valid_p) [PLUS_EXPR]: Check
+	narrowing_initializer_constant_valid_p.
+	(narrowing_initializer_constant_valid_p): Don't return 
+	null_pointer_node for adding a pointer to itself.
+
 2009-02-23  Jan Hubicka  <jh@suse.cz>
 
 	PR c/12245

gcc/testsuite/ChangeLog

 2009-02-23  Jason Merrill  <jason@redhat.com>
 
+	PR c++/38880
+	* g++.dg/init/const7.C: Remove XFAIL.
+	* g++.dg/init/static-init1.C: New test.
+
 	* g++.dg/cpp0x/initlist14.C: New test.
 
 2008-02-21  Thomas Koenig  <tkoenig@gcc.gnu.org>

gcc/testsuite/g++.dg/init/const7.C

@@ -9,5 +9,5 @@ short offsets[1] = {
 // This ensures that we get a dump whether or not the bug is present.
 void fn() { }
 
-// { dg-final { scan-tree-dump-not "initialization"  "gimple" { xfail *-*-* } } }
+// { dg-final { scan-tree-dump-not "initialization"  "gimple" } }
 // { dg-final { cleanup-tree-dump "gimple" } }

gcc/testsuite/g++.dg/init/static-init1.C

+// Related to the patch for 38880.
+// Make sure we don't think we can initialize a at compile time.
+
+char c;
+short a[] = { (short)((int)&c + (int)&c) };

gcc/varasm.c

@@ -4070,8 +4070,8 @@ constructor_static_from_elts_p (const_tree ctor)
 	  && !VEC_empty (constructor_elt, CONSTRUCTOR_ELTS (ctor)));
 }
 
-/* A subroutine of initializer_constant_valid_p.  VALUE is either a
-   MINUS_EXPR or a POINTER_PLUS_EXPR.  This looks for cases of VALUE
+/* A subroutine of initializer_constant_valid_p.  VALUE is a MINUS_EXPR,
+   PLUS_EXPR or POINTER_PLUS_EXPR.  This looks for cases of VALUE
    which are valid when ENDTYPE is an integer of any size; in
    particular, this does not accept a pointer minus a constant.  This
    returns null_pointer_node if the VALUE is an absolute constant
@@ -4124,7 +4124,9 @@ narrowing_initializer_constant_valid_p (tree value, tree endtype)
   /* Both initializers must be known.  */
   if (op0 && op1)
     {
-      if (op0 == op1)
+      if (op0 == op1
+	  && (op0 == null_pointer_node
+	      || TREE_CODE (value) == MINUS_EXPR))
 	return null_pointer_node;
 
       /* Support differences between labels.  */
@@ -4315,12 +4317,10 @@ initializer_constant_valid_p (tree value, tree endtype)
 	}
 
       /* Support narrowing pointer differences.  */
-      if (TREE_CODE (value) == POINTER_PLUS_EXPR)
-	{
-	  ret = narrowing_initializer_constant_valid_p (value, endtype);
-	  if (ret != NULL_TREE)
-	    return ret;
-	}
+      ret = narrowing_initializer_constant_valid_p (value, endtype);
+      if (ret != NULL_TREE)
+	return ret;
+
       break;
 
     case MINUS_EXPR: