diff --git a/mercurial/context.py b/mercurial/context.py
--- a/mercurial/context.py
+++ b/mercurial/context.py
@@ -2386,6 +2386,30 @@
 
         return scmutil.status(modified, added, removed, [], [], [], [])
 
+    @propertycache
+    def _copies(self):
+        p1copies = {}
+        p2copies = {}
+        p1 = self.p1()
+        p2 = self.p2()
+        narrowmatch = self._repo.narrowmatch()
+        for dst in self.files():
+            if not narrowmatch(dst) or dst not in self:
+                continue
+            copied = self[dst].renamed()
+            if not copied:
+                continue
+            src, srcnode = copied
+            if src in p1 and p1[src].filenode() == srcnode:
+                p1copies[dst] = src
+            elif src in p2 and p2[src].filenode() == srcnode:
+                p2copies[dst] = src
+        return p1copies, p2copies
+    def p1copies(self):
+        return self._copies[0]
+    def p2copies(self):
+        return self._copies[1]
+
 class memfilectx(committablefilectx):
     """memfilectx represents an in-memory file to commit.