re PR tree-optimization/64284 (ICE: Segmentation fault)

2014-12-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/64284
	* tree-ssa-threadupdate.c (duplicate_seme_region): Mark
	the loop for removal if we copied the loop header.

	* gcc.dg/torture/pr64284.c: New testcase.

From-SVN: r218733

gcc/ChangeLog

+2014-12-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/64284
+	* tree-ssa-threadupdate.c (duplicate_seme_region): Mark
+	the loop for removal if we copied the loop header.
+
 2014-12-14  Jan Hubicka  <hubicka@ucw.cz>
 
 	* ipa.c (process_references): Fix conditoinal on flag_optimize

gcc/testsuite/ChangeLog

+2014-12-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/64284
+	* gcc.dg/torture/pr64284.c: New testcase.
+
 2014-12-14  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR ipa/61602

gcc/testsuite/gcc.dg/torture/pr64284.c

+/* { dg-do compile } */
+
+int *a;
+int b;
+int
+fn1() {
+    enum { QSTRING } c = 0;
+    while (1) {
+	switch (*a) {
+	  case '\'':
+	  c = 0;
+	  default:
+	  switch (c)
+	  case 0:
+	    if (b)
+	      return 0;
+	    c = 1;
+	}
+	a++;
+    }
+}

gcc/tree-ssa-threadupdate.c

@@ -2364,7 +2364,7 @@ duplicate_seme_region (edge entry, edge exit,
 		       basic_block *region_copy)
 {
   unsigned i;
-  bool free_region_copy = false, copying_header = false;
+  bool free_region_copy = false;
   struct loop *loop = entry->dest->loop_father;
   edge exit_copy;
   edge redirected;
@@ -2388,10 +2388,7 @@ duplicate_seme_region (edge entry, edge exit,
 
   initialize_original_copy_tables ();
 
-  if (copying_header)
-    set_loop_copy (loop, loop_outer (loop));
-  else
-    set_loop_copy (loop, loop);
+  set_loop_copy (loop, loop);
 
   if (!region_copy)
     {
@@ -2453,6 +2450,8 @@ duplicate_seme_region (edge entry, edge exit,
   }
 
   /* Redirect the entry and add the phi node arguments.  */
+  if (entry->dest == loop->header)
+    mark_loop_for_removal (loop);
   redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
   gcc_assert (redirected != NULL);
   flush_pending_stmts (entry);