re PR tree-optimization/57122 (ICE in verify_loop_structure, at cfgloop.c:1647…

re PR tree-optimization/57122 (ICE in verify_loop_structure, at cfgloop.c:1647 (loop n’s latch does not have an edge to its header !))

2013-04-30  Richard Biener  <rguenther@suse.de>

	PR middle-end/57122
	* cfghooks.c (split_edge): Properly check for the loop
	latch edge.

	* gcc.dg/torture/pr57122.c: New testcase.

From-SVN: r198456

gcc/ChangeLog

 2013-04-30  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/57122
+	* cfghooks.c (split_edge): Properly check for the loop
+	latch edge.
+
+2013-04-30  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/57107
 	* tree-eh.c (sink_clobbers): Preserve virtual SSA form.
 

gcc/cfghooks.c

@@ -662,7 +662,9 @@ split_edge (edge e)
       loop = find_common_loop (src->loop_father, dest->loop_father);
       add_bb_to_loop (ret, loop);
 
-      if (loop->latch == src)
+      /* If we split the latch edge of loop adjust the latch block.  */
+      if (loop->latch == src
+	  && loop->header == dest)
 	loop->latch = ret;
     }
 

gcc/testsuite/ChangeLog

 2013-04-30  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/57122
+	* gcc.dg/torture/pr57122.c: New testcase.
+
+2013-04-30  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/57107
 	* g++.dg/torture/pr57107.C: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr57122.c

+/* { dg-do compile } */
+
+unsigned a;
+int b, c;
+
+void f(void)
+{
+  if(a)
+    {
+      for(a = 0; a < 2; a++)
+	a /= 7;
+
+      for(;; a++)
+	{
+	  if(a)
+	    lbl1:
+		b++;
+
+	  if(c)
+	    goto lbl1;
+lbl2:
+	  ;
+	}
+    }
+
+  goto lbl2;
+}