Fix PR55833.

From-SVN: r195280

5 files changed, 63 insertions, 11 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d781684..773f4d7 100644
--- a/gcc/ChangeLog
+++ b/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
diff --git a/gcc/cfgloopmanip.c b/gcc/cfgloopmanip.c
index 4875607..8c6c39d 100644
--- a/gcc/cfgloopmanip.c
+++ b/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
diff --git a/gcc/loop-unswitch.c b/gcc/loop-unswitch.c
index 25cbf18..ded0aed 100644
--- a/gcc/loop-unswitch.c
+++ b/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);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bfdb73a..1bd5ca3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/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
diff --git a/gcc/testsuite/gcc.dg/pr55833.c b/gcc/testsuite/gcc.dg/pr55833.c
new file mode 100644
index 0000000..7a5c549
--- /dev/null
+++ b/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;
+}