diff --git a/compiler/alloc.lisp b/compiler/alloc.lisp
index 09e77fbce7507a0f739ab3278007ca6a41ed10eb..913556b701305a28feb6bef82dcbf564ff55dae1 100644
--- a/compiler/alloc.lisp
+++ b/compiler/alloc.lisp
@@ -139,7 +139,8 @@
     (setf (block-in structure) nil)
     (setf (block-out structure) nil)
     (setf (block-flag structure) nil)
-    (setf (block-info structure) nil))
+    (setf (block-info structure) nil)
+    (setf (block-test-constraint structure) nil))
    ((setf (block-lambda structure) *current-lambda*)
     (setf (block-start-cleanup structure) *current-cleanup*)
     (setf (block-end-cleanup structure) *current-cleanup*)