Fix PR55833.

From-SVN: r195280

gcc/ChangeLog

@@ -1,3 +1,15 @@
+2013-01-17  Richard Biener  <rguenther@suse.de>
+	    Marek Polacek  <polacek@redhat.com>
+
+	PR rtl-optimization/55833
+	* loop-unswitch.c (unswitch_loops): Move loop verification...
+	(unswitch_single_loop): ...here.  Call mark_irreducible_loops.
+	* cfgloopmanip.c (fix_loop_placement): Add IRRED_INVALIDATED parameter.
+	Set it to true when we're removing a loop from hierarchy tree in
+	an irreducible region.
+	(fix_bb_placements): Adjust caller.
+	(fix_loop_placements): Likewise.
+
 2013-01-17  Georg-Johann Lay  <avr@gjlay.de>
 
 	* config/avr/builtins.def (DEF_BUILTIN): Factor out

gcc/cfgloopmanip.c

@@ -111,10 +111,13 @@ fix_bb_placement (basic_block bb)
 /* Fix placement of LOOP inside loop tree, i.e. find the innermost superloop
    of LOOP to that leads at least one exit edge of LOOP, and set it
    as the immediate superloop of LOOP.  Return true if the immediate superloop
-   of LOOP changed.  */
+   of LOOP changed.
+
+   IRRED_INVALIDATED is set to true if a change in the loop structures might
+   invalidate the information about irreducible regions.  */
 
 static bool
-fix_loop_placement (struct loop *loop)
+fix_loop_placement (struct loop *loop, bool *irred_invalidated)
 {
   unsigned i;
   edge e;
@@ -139,7 +142,12 @@ fix_loop_placement (struct loop *loop)
       /* The exit edges of LOOP no longer exits its original immediate
 	 superloops; remove them from the appropriate exit lists.  */
       FOR_EACH_VEC_ELT (exits, i, e)
-	rescan_loop_exit (e, false, false);
+	{
+	  /* We may need to recompute irreducible loops.  */
+	  if (e->flags & EDGE_IRREDUCIBLE_LOOP)
+	    *irred_invalidated = true;
+	  rescan_loop_exit (e, false, false);
+	}
 
       ret = true;
     }
@@ -212,7 +220,7 @@ fix_bb_placements (basic_block from,
       if (from->loop_father->header == from)
 	{
 	  /* Subloop header, maybe move the loop upward.  */
-	  if (!fix_loop_placement (from->loop_father))
+	  if (!fix_loop_placement (from->loop_father, irred_invalidated))
 	    continue;
 	  target_loop = loop_outer (from->loop_father);
 	}
@@ -965,7 +973,7 @@ fix_loop_placements (struct loop *loop, bool *irred_invalidated)
   while (loop_outer (loop))
     {
       outer = loop_outer (loop);
-      if (!fix_loop_placement (loop))
+      if (!fix_loop_placement (loop, irred_invalidated))
 	break;
 
       /* Changing the placement of a loop in the loop tree may alter the

gcc/loop-unswitch.c

@@ -144,12 +144,7 @@ unswitch_loops (void)
   /* Go through inner loops (only original ones).  */
 
   FOR_EACH_LOOP (li, loop, LI_ONLY_INNERMOST)
-    {
-      unswitch_single_loop (loop, NULL_RTX, 0);
-#ifdef ENABLE_CHECKING
-      verify_loop_structure ();
-#endif
-    }
+    unswitch_single_loop (loop, NULL_RTX, 0);
 
   iv_analysis_done ();
 }
@@ -369,6 +364,10 @@ unswitch_single_loop (struct loop *loop, rtx cond_checked, int num)
   nloop = unswitch_loop (loop, bbs[i], copy_rtx_if_shared (cond), cinsn);
   gcc_assert (nloop);
 
+#ifdef ENABLE_CHECKING
+  verify_loop_structure ();
+#endif
+
   /* Invoke itself on modified loops.  */
   unswitch_single_loop (nloop, rconds, num + 1);
   unswitch_single_loop (loop, conds, num + 1);

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2013-01-17  Marek Polacek  <polacek@redhat.com>
+
+	PR rtl-optimization/55833
+	* gcc.dg/pr55833.c: New test.
+
 2013-01-17  Jan Hubicka  <jh@suse.cz>
 
 	PR tree-optimization/55273

gcc/testsuite/gcc.dg/pr55833.c

@@ -0,0 +1,28 @@
+/* PR rtl-optimization/55833 */
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+int a, b, c;
+
+void foo()
+{
+    unsigned d, l, *p, k = 1;
+
+    if(bar())
+    {
+label:
+      	if((a = a <= 0))
+        {
+            if(c)
+                d = b;
+
+            if (b || d ? l : k ? : 0)
+                a = d = 0;
+
+            goto label;
+       	}
+    }
+
+    while(*p++)
+        goto label;
+}