diff -r 577f65cf1a57 -r 59cc09240afb mercurial/localrepo.py
--- a/mercurial/localrepo.py	Tue Mar 17 14:29:56 2015 -0700
+++ b/mercurial/localrepo.py	Tue Feb 10 19:53:48 2015 -0800
@@ -279,6 +279,7 @@
 
 
         self._branchcaches = {}
+        self._revbranchcache = None
         self.filterpats = {}
         self._datafilters = {}
         self._transref = self._lockref = self._wlockref = None
@@ -726,6 +727,12 @@
         branchmap.updatecache(self)
         return self._branchcaches[self.filtername]
 
+    @unfilteredmethod
+    def revbranchcache(self):
+        if not self._revbranchcache:
+            self._revbranchcache = branchmap.revbranchcache(self.unfiltered())
+        return self._revbranchcache
+
     def branchtip(self, branch, ignoremissing=False):
         '''return the tip node for a given branch