Strenghten assumption about gswitch statements.

2018-08-29  Martin Liska  <mliska@suse.cz>

	* tree-switch-conversion.c (switch_conversion::expand):
	Strenghten assumption about gswitch statements.

From-SVN: r263947

gcc/ChangeLog

+2018-08-29  Martin Liska  <mliska@suse.cz>
+
+	* tree-switch-conversion.c (switch_conversion::expand):
+	Strenghten assumption about gswitch statements.
+
 2018-08-29  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/87117

gcc/tree-switch-conversion.c

@@ -913,14 +913,7 @@ switch_conversion::expand (gswitch *swtch)
   /* Group case labels so that we get the right results from the heuristics
      that decide on the code generation approach for this switch.  */
   m_cfg_altered |= group_case_labels_stmt (swtch);
-
-  /* If this switch is now a degenerate case with only a default label,
-     there is nothing left for us to do.  */
-  if (gimple_switch_num_labels (swtch) < 2)
-    {
-      m_reason = "switch is a degenerate case";
-      return;
-    }
+  gcc_assert (gimple_switch_num_labels (swtch) >= 2);
 
   collect (swtch);