From 335716b81d99c7476e68979fe48b20b0f2bfeeee Mon Sep 17 00:00:00 2001
From: dgp <dgp@users.sourceforge.net>
Date: Fri, 28 Oct 2016 14:45:54 +0000
Subject: Add obvious optimizations to [join] implementation.

---
 generic/tclCmdIL.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/generic/tclCmdIL.c b/generic/tclCmdIL.c
index bb3c9b7..7f4ca1d 100644
--- a/generic/tclCmdIL.c
+++ b/generic/tclCmdIL.c
@@ -2173,6 +2173,16 @@ Tcl_JoinObjCmd(
 	return TCL_ERROR;
     }
 
+    if (listLen == 0) {
+	/* No elements to join; default empty result is correct. */
+	return TCL_OK;
+    }
+    if (listLen == 1) {
+	/* One element; return it */
+	Tcl_SetObjResult(interp, elemPtrs[0]);
+	return TCL_OK;
+    }
+
     joinObjPtr = (objc == 2) ? Tcl_NewStringObj(" ", 1) : objv[2];
     Tcl_IncrRefCount(joinObjPtr);
 
-- 
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