--- a/mercurial/pure/bdiff.py	Tue May 02 21:04:40 2017 +0900
+++ b/mercurial/pure/bdiff.py	Tue May 02 21:08:38 2017 +0900
@@ -96,7 +96,7 @@
 
 if modulepolicy not in policynocffi:
     try:
-        from _bdiff_cffi import ffi, lib
+        from ..cffi._bdiff import ffi, lib
     except ImportError:
         if modulepolicy == 'cffi': # strict cffi import
             raise