From 73c5c94ba163dd66fd02eb9165d5667d69d53e28 Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Sat, 12 Jan 2019 13:03:05 -0800
Subject: [PATCH] Eliminate unnecessary consing in char-set-empty?.

---
 src/runtime/char-set.scm | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/runtime/char-set.scm b/src/runtime/char-set.scm
index 0f4277c2e..bca760cb0 100644
--- a/src/runtime/char-set.scm
+++ b/src/runtime/char-set.scm
@@ -446,6 +446,10 @@ USA.
 			      (%char-set-high char-set))))
 	 char-sets))
 
+(define (char-set-empty? cs)
+  (and (fix:= 0 (bytevector-length (%char-set-low cs)))
+       (fix:= 0 (bytevector-length (%char-set-high cs)))))
+
 (define (char-set-hash char-set)
   (primitive-object-hash-2 (%char-set-low char-set)
 			   (%char-set-high char-set)))
@@ -458,9 +462,6 @@ USA.
 		    ranges))
 	(reverse! ranges))))
 
-(define (char-set-empty? cs)
-  (char-set=? (char-set) cs))
-
 (define (char-sets-disjoint? char-set . char-sets)
   (every (lambda (char-set*)
 	   (char-set-empty? (char-set-intersection char-set char-set*)))
-- 
2.25.1