re PR c++/63203 (Self-initialization of reference not diagnosed if it occurs within a loop)

/cp
2014-11-24  Jonathan Wakely  <jwakely@redhat.com>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/63203
	* decl.c (initialize_local_var): Add -Winit-self warning for
	references initialized with themselves.

/testsuite
2014-11-24  Jonathan Wakely  <jwakely@redhat.com>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/63203
	* g++.dg/warn/Winit-self-2.C: New.

Co-Authored-By: Paolo Carlini <paolo.carlini@oracle.com>

From-SVN: r218017

gcc/cp/ChangeLog

+2014-11-24  Jonathan Wakely  <jwakely@redhat.com>
+	    Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/63203
+	* decl.c (initialize_local_var): Add -Winit-self warning for
+	references initialized with themselves.
+
 2014-11-24  Jason Merrill  <jason@redhat.com>
 
 	PR c++/63942

gcc/cp/decl.c

@@ -6132,13 +6132,23 @@ initialize_local_var (tree decl, tree init)
   /* Perform the initialization.  */
   if (init)
     {
-      if (TREE_CODE (init) == INIT_EXPR
-	  && !TREE_SIDE_EFFECTS (TREE_OPERAND (init, 1)))
+      tree rinit = (TREE_CODE (init) == INIT_EXPR
+		    ? TREE_OPERAND (init, 1) : NULL_TREE);
+      if (rinit && !TREE_SIDE_EFFECTS (rinit))
 	{
 	  /* Stick simple initializers in DECL_INITIAL so that
 	     -Wno-init-self works (c++/34772).  */
 	  gcc_assert (TREE_OPERAND (init, 0) == decl);
-	  DECL_INITIAL (decl) = TREE_OPERAND (init, 1);
+	  DECL_INITIAL (decl) = rinit;
+
+	  if (warn_init_self && TREE_CODE (type) == REFERENCE_TYPE)
+	    {
+	      STRIP_NOPS (rinit);
+	      if (rinit == decl)
+		warning_at (DECL_SOURCE_LOCATION (decl),
+			    OPT_Winit_self,
+			    "reference %qD is initialized with itself", decl);
+	    }
 	}
       else
 	{

gcc/testsuite/ChangeLog

+2014-11-24  Jonathan Wakely  <jwakely@redhat.com>
+	    Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/63203
+	* g++.dg/warn/Winit-self-2.C: New.
+
 2014-11-24  Petr Murzin  <petr.murzin@intel.com>
 
 	* gcc.target/i386/extract-insert-combining.c: New test.

gcc/testsuite/g++.dg/warn/Winit-self-2.C

+// PR c++/63203
+// { dg-options "-Winit-self" }
+
+struct string { };
+
+int main()
+{
+  for (int ii = 0; ii < 1; ++ii)
+  {
+    const string& str = str;  // { dg-warning "is initialized with itself" }
+  }
+}