--- a/mercurial/cmdutil.py	Wed Sep 09 12:40:57 2015 -0700
+++ b/mercurial/cmdutil.py	Wed Sep 09 09:07:27 2015 -0700
@@ -2208,7 +2208,12 @@
     if abort or warn:
         cca = scmutil.casecollisionauditor(ui, abort, repo.dirstate)
 
-    for f in wctx.walk(matchmod.badmatch(match, badfn)):
+    badmatch = matchmod.badmatch(match, badfn)
+    dirstate = repo.dirstate
+    # We don't want to just call wctx.walk here, since it would return a lot of
+    # clean files, which we aren't interested in and takes time.
+    for f in sorted(dirstate.walk(badmatch, sorted(wctx.substate),
+                                  True, False, full=False)):
         exact = match.exact(f)
         if exact or not explicitonly and f not in wctx and repo.wvfs.lexists(f):
             if cca: