From 4acc34540584a4f72ed54661ad866ce3f25360c5 Mon Sep 17 00:00:00 2001
From: Yihe Dong <yihedong@gmail.com>
Date: Wed, 7 Mar 2018 12:12:06 -0600
Subject: [PATCH] =?UTF-8?q?use=20empirically=20found=20threshold=20to=20sp?=
 =?UTF-8?q?eed=20up=20issubset=20by=20creating=20Set=20=E2=80=A6=20(#26198?=
 =?UTF-8?q?)?=
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---
 base/abstractset.jl | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/base/abstractset.jl b/base/abstractset.jl
index 8291adf517922..2e81f258cb737 100644
--- a/base/abstractset.jl
+++ b/base/abstractset.jl
@@ -215,6 +215,16 @@ false
 ```
 """
 function issubset(l, r)
+
+    rlen = length(r)
+    #This threshold was empirically determined by repeatedly
+    #sampling using these two methods.
+    lenthresh = 70
+
+    if rlen > lenthresh && !isa(r, AbstractSet)
+       return issubset(l, Set(r))
+    end
+
     for elt in l
         if !in(elt, r)
             return false