diff --git a/basis/compiler/cfg/builder/builder-tests.factor b/basis/compiler/cfg/builder/builder-tests.factor
index 9677dc30ca..73d1204c37 100644
--- a/basis/compiler/cfg/builder/builder-tests.factor
+++ b/basis/compiler/cfg/builder/builder-tests.factor
@@ -224,3 +224,9 @@ IN: compiler.cfg.builder.tests
 
 ! Regression. Make sure branch splitting works.
 [ 2 ] [ [ 1 2 ? ] [ ##return? ] count-insns ] unit-test
+
+! Make sure fast union predicates don't have conditionals.
+[ f ] [
+    [ tag 1 swap fixnum-shift-fast ]
+    [ ##compare-integer-imm-branch? ] contains-insn?
+] unit-test