Fix thinko in early bail out in tree-switch-conversion.

2019-09-02  Martin Liska  <mliska@suse.cz>

	* tree-switch-conversion.c (jump_table_cluster::find_jump_tables):
	Bail out when we'll end up with the same number of clusters as
	at the beginning.
	(bit_test_cluster::find_bit_tests): Likewise for bit tests.
	(jump_table_cluster::can_be_handled): Remove the guard
	as it's already handled in ::is_enabled.  Allocate output
	after early bail out.

From-SVN: r275293

gcc/ChangeLog

 2019-09-02  Martin Liska  <mliska@suse.cz>
 
+	* tree-switch-conversion.c (jump_table_cluster::find_jump_tables):
+	Bail out when we'll end up with the same number of clusters as
+	at the beginning.
+	(bit_test_cluster::find_bit_tests): Likewise for bit tests.
+	(jump_table_cluster::can_be_handled): Remove the guard
+	as it's already handled in ::is_enabled.  Allocate output
+	after early bail out.
+
+2019-09-02  Martin Liska  <mliska@suse.cz>
+
 	PR gcov-profile/91601
 	* gcov.c (path_contains_zero_cycle_arc): Rename to ...
 	(path_contains_zero_or_negative_cycle_arc): ... this and handle

gcc/tree-switch-conversion.c

@@ -1214,14 +1214,14 @@ jump_table_cluster::find_jump_tables (vec<cluster *> &clusters)
     }
 
   /* No result.  */
-  if (min[l].m_count == INT_MAX)
+  if (min[l].m_count == l)
     return clusters.copy ();
 
   vec<cluster *> output;
   output.create (4);
 
   /* Find and build the clusters.  */
-  for (int end = l;;)
+  for (unsigned int end = l;;)
     {
       int start = min[end].m_start;
 
@@ -1258,11 +1258,9 @@ jump_table_cluster::can_be_handled (const vec<cluster *> &clusters,
      make a sequence of conditional branches instead of a dispatch.
 
      The definition of "much bigger" depends on whether we are
-     optimizing for size or for speed.  */
-  if (!flag_jump_tables)
-    return false;
+     optimizing for size or for speed.
 
-  /* For algorithm correctness, jump table for a single case must return
+     For algorithm correctness, jump table for a single case must return
      true.  We bail out in is_beneficial if it's called just for
      a single case.  */
   if (start == end)
@@ -1312,9 +1310,6 @@ jump_table_cluster::is_beneficial (const vec<cluster *> &,
 vec<cluster *>
 bit_test_cluster::find_bit_tests (vec<cluster *> &clusters)
 {
-  vec<cluster *> output;
-  output.create (4);
-
   unsigned l = clusters.length ();
   auto_vec<min_cluster_item> min;
   min.reserve (l + 1);
@@ -1337,9 +1332,12 @@ bit_test_cluster::find_bit_tests (vec<cluster *> &clusters)
     }
 
   /* No result.  */
-  if (min[l].m_count == INT_MAX)
+  if (min[l].m_count == l)
     return clusters.copy ();
 
+  vec<cluster *> output;
+  output.create (4);
+
   /* Find and build the clusters.  */
   for (unsigned end = l;;)
     {