diff --git a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-docs.factor b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-docs.factor
index 0715fa9271..01da78a297 100644
--- a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-docs.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-docs.factor
@@ -32,8 +32,8 @@ HELP: split-for-spill
 { $values
   { "live-interval" live-interval-state }
   { "n" integer }
-  { "before" live-interval-state }
-  { "after" live-interval-state }
+  { "before/f" $maybe live-interval-state }
+  { "after/f" $maybe live-interval-state }
 } { $description "During register allocation an interval needs to be split so that the 'after' part of it can be placed in a spill slot." } ;
 
 HELP: spill-intersecting
diff --git a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-tests.factor b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-tests.factor
index 62e429d60b..23195d76be 100644
--- a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-tests.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling-tests.factor
@@ -36,6 +36,11 @@ IN: compiler.cfg.linear-scan.allocation.spilling.tests
     test-live-interval last-use-rep
 ] unit-test
 
+! spill-before
+{ f } [
+    30 <live-interval> spill-before
+] unit-test
+
 ! trim-after-ranges
 {
     T{ live-interval-state
diff --git a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
index d1901a3509..cb7893a340 100644
--- a/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
+++ b/basis/compiler/cfg/linear-scan/allocation/spilling/spilling.factor
@@ -61,7 +61,7 @@ ERROR: bad-live-ranges interval ;
         } cleave
     ] if ;
 
-: split-for-spill ( live-interval n -- before after )
+: split-for-spill ( live-interval n -- before/f after/f )
     split-interval [ spill-before ] [ spill-after ] bi* ;
 
 : find-next-use ( live-interval new -- n )
@@ -96,8 +96,7 @@ ERROR: bad-live-ranges interval ;
 
 : spill ( live-interval n -- )
     split-for-spill
-    [ [ add-handled ] when* ]
-    [ [ add-unhandled ] when* ] bi* ;
+    [ [ add-handled ] when* ] [ [ add-unhandled ] when* ] bi* ;
 
 :: spill-intersecting-active ( new reg -- )
     new active-intervals-for [ [ reg>> reg = ] find swap dup ] keep