diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ec1458c1192..945e9046de8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-04-11  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/52918
+	* except.c (sjlj_emit_dispatch_table): Properly update loop
+	structure.
+
 2012-04-11  Nick Clifton  <nickc@redhat.com>
 
 	* config/rl78/rl78.c (rl78_expand_prologue): Set stack use
diff --git a/gcc/except.c b/gcc/except.c
index e3a9ef07422..e6e7794f246 100644
--- a/gcc/except.c
+++ b/gcc/except.c
@@ -1344,6 +1344,28 @@ sjlj_emit_dispatch_table (rtx dispatch_label, int num_dispatch)
 	e = make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
 	e->count = bb->count;
 	e->probability = REG_BR_PROB_BASE;
+	if (current_loops)
+	  {
+	    struct loop *loop = bb->next_bb->loop_father;
+	    /* If we created a pre-header block, add the new block to the
+	       outer loop, otherwise to the loop itself.  */
+	    if (bb->next_bb == loop->header)
+	      add_bb_to_loop (bb, loop_outer (loop));
+	    else
+	      add_bb_to_loop (bb, loop);
+	    /* ???  For multiple dispatches we will end up with edges
+	       from the loop tree root into this loop, making it a
+	       multiple-entry loop.  Discard all affected loops.  */
+	    if (num_dispatch > 1)
+	      {
+		for (loop = bb->loop_father;
+		     loop_outer (loop); loop = loop_outer (loop))
+		  {
+		    loop->header = NULL;
+		    loop->latch = NULL;
+		  }
+	      }
+	  }
 
 	disp_index++;
       }
@@ -1364,6 +1386,24 @@ sjlj_emit_dispatch_table (rtx dispatch_label, int num_dispatch)
       e = make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
       e->count = bb->count;
       e->probability = REG_BR_PROB_BASE;
+      if (current_loops)
+	{
+	  struct loop *loop = bb->next_bb->loop_father;
+	  /* If we created a pre-header block, add the new block to the
+	     outer loop, otherwise to the loop itself.  */
+	  if (bb->next_bb == loop->header)
+	    add_bb_to_loop (bb, loop_outer (loop));
+	  else
+	    add_bb_to_loop (bb, loop);
+	}
+    }
+  else
+    {
+      /* We are not wiring up edges here, but as the dispatcher call
+         is at function begin simply associate the block with the
+	 outermost (non-)loop.  */
+      if (current_loops)
+	add_bb_to_loop (bb, current_loops->tree_root);
     }
 }
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d657e47ee60..7e2a1c30b8e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2012-04-11  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/52918
+	* g++.dg/torture/pr52918-1.C: New testcase.
+	* g++.dg/torture/pr52918-2.C: Likewise.
+
 2012-04-11  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/52729
diff --git a/gcc/testsuite/g++.dg/torture/pr52918-1.C b/gcc/testsuite/g++.dg/torture/pr52918-1.C
new file mode 100644
index 00000000000..9e7b21ba6a3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr52918-1.C
@@ -0,0 +1,39 @@
+// { dg-do compile }
+
+typedef __SIZE_TYPE__ size_t;
+class bad_alloc   { };
+typedef struct {
+} __gthread_mutex_t;
+int __gthread_mutex_unlock (__gthread_mutex_t *__mutex);
+class __concurrence_unlock_error   {
+};
+inline void   __throw_concurrence_unlock_error()   {
+    throw __concurrence_unlock_error();
+}
+class __mutex   {
+    __gthread_mutex_t _M_mutex;
+public:
+    void unlock()     {
+	if (__gthread_mutex_unlock(&_M_mutex) != 0)
+	  __throw_concurrence_unlock_error();  	   
+    }
+};
+class free_list   {
+    typedef __mutex __mutex_type;
+    __mutex_type&     _M_get_mutex();
+    void _M_get(size_t __sz) throw(bad_alloc);
+};
+void  free_list::_M_get(size_t __sz) throw(bad_alloc)
+{
+  __mutex_type& __bfl_mutex = _M_get_mutex();
+  __bfl_mutex.unlock();
+  int __ctr = 2;
+  while (__ctr)  {
+      size_t* __ret = 0;
+      --__ctr;
+      try {
+	  __ret = (size_t*) (::operator new(__sz + sizeof(size_t)));       
+      }
+      catch(const bad_alloc&) { }
+  }
+}
diff --git a/gcc/testsuite/g++.dg/torture/pr52918-2.C b/gcc/testsuite/g++.dg/torture/pr52918-2.C
new file mode 100644
index 00000000000..ba31295e41e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr52918-2.C
@@ -0,0 +1,40 @@
+// { dg-do compile }
+
+typedef __SIZE_TYPE__ size_t;
+void*   __cxa_allocate_exception(size_t) throw();
+typedef struct { } __gthread_mutex_t;
+extern int __gthr_win32_mutex_unlock (__gthread_mutex_t *);
+int __gthread_mutex_lock (__gthread_mutex_t *__mutex);
+int __gthread_mutex_unlock (__gthread_mutex_t *__mutex);
+void   __throw_concurrence_lock_error();
+void   __throw_concurrence_unlock_error();
+class __mutex   {
+    __gthread_mutex_t _M_mutex;
+public:
+    void lock()     {
+	if (__gthread_mutex_lock(&_M_mutex) != 0)
+	  __throw_concurrence_lock_error();
+    }
+    void unlock()     {
+	if (__gthread_mutex_unlock(&_M_mutex) != 0) 
+	  __throw_concurrence_unlock_error();
+    }
+};
+class __scoped_lock   {
+    typedef __mutex __mutex_type;
+    __mutex_type& _M_device;
+public:
+    explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)     {
+	_M_device.lock();
+    }
+    ~__scoped_lock() throw()    {
+	_M_device.unlock();
+    }
+};
+__mutex emergency_mutex;
+void * __cxa_allocate_exception(size_t thrown_size) throw()
+{
+  void *ret;
+  if (! ret)     
+    __scoped_lock sentry(emergency_mutex);
+}