[Guile-commits] 02/09: intset-union fast paths

[Andy Wingo]

wingo pushed a commit to branch master
in repository guile.

commit 47a4727b78c146adc24cbfbeeabc3abf022e14f8
Author: Andy Wingo <address@hidden>
Date:   Mon Jul 13 11:02:29 2015 +0200

    intset-union fast paths
    
    * module/language/cps/intset.scm (intset-union): Add fast paths for
      union with empty intset.
---
 module/language/cps/intset.scm |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/module/language/cps/intset.scm b/module/language/cps/intset.scm
index 87956c5..7f8316e 100644
--- a/module/language/cps/intset.scm
+++ b/module/language/cps/intset.scm
@@ -508,6 +508,8 @@
   (match (cons a b)
     ((($ <intset> a-min a-shift a-root) . ($ <intset> b-min b-shift b-root))
      (cond
+      ((not b-root) a)
+      ((not a-root) b)
       ((not (= b-shift a-shift))
        ;; Hoist the set with the lowest shift to meet the one with the
        ;; higher shift.