factor: use ??if instead of ?if-old

[factor.git] / basis / compiler / cfg / rpo / rpo.factor

diff --git a/basis/compiler/cfg/rpo/rpo.factor b/basis/compiler/cfg/rpo/rpo.factor
index 0ecbc510ae5d9732fcb890e09a1dcf949a42dab7..692c01114e7a6ce8429b0c04357700734292f7cf 100644 (file)
--- a/basis/compiler/cfg/rpo/rpo.factor
+++ b/basis/compiler/cfg/rpo/rpo.factor
@@ -17,13 +17,13 @@ IN: compiler.cfg.rpo
     [ >>number drop ] 2each ;
 
 : post-order ( cfg -- blocks )
-    dup post-order>> [ ] [
+    [ post-order>> ] [
         [
             HS{ } clone over entry>>
             post-order-traversal drop
         ] { } make dup number-blocks
         >>post-order post-order>>
-    ] ?if ;
+    ] ?unless ;
 
 : reverse-post-order ( cfg -- blocks )
     post-order <reversed> ; inline