Index: ext/bigdecimal/bigdecimal.c
===================================================================
--- ext/bigdecimal/bigdecimal.c	(revision 34755)
+++ ext/bigdecimal/bigdecimal.c	(working copy)
@@ -971,6 +971,8 @@ BigDecimalCmp(VALUE self, VALUE r,char o
     }
 
     rb_bug("Undefined operation in BigDecimalCmp()");
+
+    return Qnil; /* not reached */
 }
 
 /* Returns True if the value is zero. */