c-typeck.c (build_c_cast): Check type punning on COMPONENT_REF too.

/:
	* c-typeck.c (build_c_cast): Check type punning on COMPONENT_REF
	too.
testsuite:
	* gcc.dg/alias-8.c: New.

From-SVN: r100799

gcc/ChangeLog

+2005-06-09  Nathan Sidwell  <nathan@codesourcery.com>
+
+	* c-typeck.c (build_c_cast): Check type punning on COMPONENT_REF
+	too.
+
 2005-06-09  Bernd Schmidt  <bernd.schmidt@analog.com>
 
 	* config/bfin/bfin.c (enum bfin_builtins): Moved here from...

gcc/c-typeck.c

@@ -3304,14 +3304,15 @@ build_c_cast (tree type, tree expr)
 	  && !TREE_CONSTANT (value))
 	warning (0, "cast to pointer from integer of different size");
 
-      if (TREE_CODE (type) == POINTER_TYPE
+      if (flag_strict_aliasing && warn_strict_aliasing
+	  && TREE_CODE (type) == POINTER_TYPE
 	  && TREE_CODE (otype) == POINTER_TYPE
 	  && TREE_CODE (expr) == ADDR_EXPR
-	  && DECL_P (TREE_OPERAND (expr, 0))
-	  && flag_strict_aliasing && warn_strict_aliasing
+	  && (DECL_P (TREE_OPERAND (expr, 0))
+	      || TREE_CODE (TREE_OPERAND (expr, 0)) == COMPONENT_REF)
 	  && !VOID_TYPE_P (TREE_TYPE (type)))
 	{
-	  /* Casting the address of a decl to non void pointer. Warn
+	  /* Casting the address of an object to non void pointer. Warn
 	     if the cast breaks type based aliasing.  */
 	  if (!COMPLETE_TYPE_P (TREE_TYPE (type)))
 	    warning (0, "type-punning to incomplete type might break strict-aliasing rules");

gcc/testsuite/ChangeLog

+2005-06-09  Nathan Sidwell  <nathan@codesourcery.com>
+
+	* gcc.dg/alias-8.c: New.
+
 2005-06-08  Joseph S. Myers  <joseph@codesourcery.com>
 
 	* gcc.dg/format/cmn_err-1.c: Update.

gcc/testsuite/gcc.dg/alias-8.c

+// { dg-do compile }
+// { dg-options "-Wstrict-aliasing=2 -fstrict-aliasing" }
+
+struct s {
+  char    *p;
+};
+
+void
+func(struct s *ptr)
+{
+  *(void **)&ptr->p = 0; /* { dg-warning "type-punned pointer" } */
+}