re PR rtl-optimization/85455 (ICE in verify_loop_structure, at cfgloop.c:1708…

re PR rtl-optimization/85455 (ICE in verify_loop_structure, at cfgloop.c:1708 (error: basic block 3 should be marked irreducible))

2018-04-19  Richard Biener  <rguenther@suse.de>

	PR middle-end/85455
	* cfg.c (clear_bb_flags): When loop state says we have
	marked irreducible regions also preserve BB_IRREDUCIBLE_LOOP.

	* gcc.dg/pr85455.c: New testcase.

From-SVN: r259494

gcc/ChangeLog

 2018-04-19  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/85455
+	* cfg.c (clear_bb_flags): When loop state says we have
+	marked irreducible regions also preserve BB_IRREDUCIBLE_LOOP.
+
+2018-04-19  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/84737
 	* tree-vect-data-refs.c (vect_copy_ref_info): New function
 	copying restrict info.

gcc/cfg.c

@@ -386,9 +386,13 @@ void
 clear_bb_flags (void)
 {
   basic_block bb;
+  int flags_to_preserve = BB_FLAGS_TO_PRESERVE;
+  if (current_loops
+      && loops_state_satisfies_p (cfun, LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
+    flags_to_preserve |= BB_IRREDUCIBLE_LOOP;
 
   FOR_ALL_BB_FN (bb, cfun)
-    bb->flags &= BB_FLAGS_TO_PRESERVE;
+    bb->flags &= flags_to_preserve;
 }
 
 /* Check the consistency of profile information.  We can't do that

gcc/testsuite/ChangeLog

+2018-04-19  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/85455
+	* gcc.dg/pr85455.c: New testcase.
+
 2018-04-19  Christophe Lyon  <christophe.lyon@linaro.org>
 
 	* g++.dg/lto/pr85405_0.C: Require shared and fpic effective

gcc/testsuite/gcc.dg/pr85455.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -fthread-jumps -fno-tree-dominator-opts -fno-tree-reassoc -fno-tree-sink -fno-tree-slsr" } */
+
+void
+ty (void);
+
+void
+um (void);
+
+void
+au (int qj)
+{
+  if (qj < 1)
+    {
+vq:
+      ty ();
+    }
+
+  um ();
+
+  goto vq;
+}