re PR c++/28294 (ICE with invalid use of __builtin_offsetof)

	PR c++/28294
	* semantics.c (finish_offsetof): Use TREE_OPERAND for COMPONENT_REFs
	only.

	* g++.dg/ext/offsetof1.C: Add test with function pointer arithmetic.

From-SVN: r115466

gcc/cp/ChangeLog

 2006-07-15  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
+	PR c++/28294
+	* semantics.c (finish_offsetof): Use TREE_OPERAND for COMPONENT_REFs
+	only.
+
 	PR c++/28387
 	* decl2.c (cplus_decl_attributes): Check for invalid decls.
 

gcc/cp/semantics.c

@@ -2905,8 +2905,9 @@ finish_offsetof (tree expr)
       || TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE
       || TREE_CODE (TREE_TYPE (expr)) == UNKNOWN_TYPE)
     {
-      error ("cannot apply %<offsetof%> to member function %qD",
-	     TREE_OPERAND (expr, 1));
+      if (TREE_CODE (expr) == COMPONENT_REF)
+	expr = TREE_OPERAND (expr, 1);
+      error ("cannot apply %<offsetof%> to member function %qD", expr);
       return error_mark_node;
     }
   return fold_offsetof (expr);

gcc/testsuite/ChangeLog

 2006-07-15  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
+	PR c++/28294
+	* g++.dg/ext/offsetof1.C: Add test with function pointer arithmetic.
+
 	PR c++/28387
 	* g++.dg/ext/attrib24.C: New test.
 

gcc/testsuite/g++.dg/ext/offsetof1.C

@@ -9,6 +9,7 @@ struct bar {
 
 int a = __builtin_offsetof(bar, foo);  // { dg-error "static data member" }
 int b = __builtin_offsetof(bar, baz);  // { dg-error "member function" }
+int b0 = __builtin_offsetof(bar, baz[0]);  // { dg-error "function" }
 int c = __builtin_offsetof(bar, ~bar);  // { dg-error "member function" }
 
 typedef int I;