diff --git a/basis/compiler/tests/codegen.factor b/basis/compiler/tests/codegen.factor
index 288940e660..2edb016734 100644
--- a/basis/compiler/tests/codegen.factor
+++ b/basis/compiler/tests/codegen.factor
@@ -462,3 +462,13 @@ TUPLE: myseq { underlying1 byte-array read-only } { underlying2 byte-array read-
     1 1
     [ [ HEX: f bitand ] bi@ [ shift ] [ drop -3 shift ] 2bi ] compile-call
 ] unit-test
+
+! GC root offsets were computed wrong on x86
+: gc-root-messup ( a -- b )
+    dup [
+        1024 (byte-array) 2array
+        10 void* "libc" "malloc" { ulong } alien-invoke
+        void "libc" "free" { void* } alien-invoke
+    ] when ;
+
+[ ] [ 2000 [ "hello" clone dup gc-root-messup first eq? t assert= ] times ] unit-test
diff --git a/basis/cpu/x86/x86.factor b/basis/cpu/x86/x86.factor
index 6019a5af8b..d4a3be49b6 100644
--- a/basis/cpu/x86/x86.factor
+++ b/basis/cpu/x86/x86.factor
@@ -45,7 +45,7 @@ HOOK: extra-stack-space cpu ( stack-frame -- n )
 : param@ ( n -- op ) reserved-stack-space + stack@ ;
 
 : gc-root-offsets ( seq -- seq' )
-    [ n>> special-offset ] map f like ;
+    [ n>> spill-offset special-offset ] map f like ;
 
 : decr-stack-reg ( n -- )
     dup 0 = [ drop ] [ stack-reg swap SUB ] if ;