2012-10-29 Richard Guenther <rguenther@suse.de>

	PR middle-end/53695
	* tracer.c (tracer): Fixup loop structure.
	* cfgloopmanip.c (force_single_succ_latches): Add assert.
	(fix_loop_structure): Re-compute loop latches and disambiguate
	loops with multiple latches if required.

	* gcc.dg/torture/pr53695.c: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@192943 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 60 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 280e29a8529..e32ede06b0a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2012-10-29  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/53695
+	* tracer.c (tracer): Fixup loop structure.
+	* cfgloopmanip.c (force_single_succ_latches): Add assert.
+	(fix_loop_structure): Re-compute loop latches and disambiguate
+	loops with multiple latches if required.
+
 2012-10-29  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/i386.c (ix86_decompose_address): Use simplify_gen_subreg
diff --git a/gcc/cfgloopmanip.c b/gcc/cfgloopmanip.c
index eae68ca43c7..b48e85883ce 100644
--- a/gcc/cfgloopmanip.c
+++ b/gcc/cfgloopmanip.c
@@ -1586,6 +1586,7 @@ force_single_succ_latches (void)
 	continue;
 
       e = find_edge (loop->latch, loop->header);
+      gcc_checking_assert (e != NULL);
 
       split_edge (e);
     }
@@ -1848,6 +1849,32 @@ fix_loop_structure (bitmap changed_bbs)
 	}
     }
 
+  /* Then re-compute the single latch if there is one.  */
+  FOR_EACH_LOOP (li, loop, 0)
+    {
+      edge_iterator ei;
+      edge e, latch = NULL;
+      FOR_EACH_EDGE (e, ei, loop->header->preds)
+	if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header))
+	  {
+	    if (!latch)
+	      latch = e;
+	    else
+	      {
+		latch = NULL;
+		break;
+	      }
+	  }
+      if (latch
+	  && latch->src->loop_father == loop)
+	loop->latch = latch->src;
+      else
+	loop->latch = NULL;
+    }
+
+  if (!loops_state_satisfies_p (LOOPS_MAY_HAVE_MULTIPLE_LATCHES))
+    disambiguate_loops_with_multiple_latches ();
+
   if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS))
     create_preheaders (CP_SIMPLE_PREHEADERS);
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0e1f365339b..d07052b6453 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-10-29  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/53695
+	* gcc.dg/torture/pr53695.c: New testcase.
+
 2012-10-28  Jan Hubicka  <jh@suse.cz>
 
 	* gcc.dg/ipa/inlinehint-3.c: New testcase.
diff --git a/gcc/testsuite/gcc.dg/torture/pr53695.c b/gcc/testsuite/gcc.dg/torture/pr53695.c
new file mode 100644
index 00000000000..eba0843c4a2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr53695.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-ftracer" } */
+
+void
+foo (const void **p)
+{
+  void *labs[] = { &&l1, &&l2, &&l3 };
+l1:
+  goto *p++;
+l2:
+  goto *p;
+l3:
+  ;
+}
diff --git a/gcc/tracer.c b/gcc/tracer.c
index 9b1d724085c..7264ad2589b 100644
--- a/gcc/tracer.c
+++ b/gcc/tracer.c
@@ -379,7 +379,12 @@ tracer (void)
   /* Trace formation is done on the fly inside tail_duplicate */
   changed = tail_duplicate ();
   if (changed)
-    free_dominance_info (CDI_DOMINATORS);
+    {
+      free_dominance_info (CDI_DOMINATORS);
+      calculate_dominance_info (CDI_DOMINATORS);
+      if (current_loops)
+	fix_loop_structure (NULL);
+    }
 
   if (dump_file)
     brief_dump_cfg (dump_file, dump_flags);