From a90803a4d1bc47fcfc3b9a3af519cd8441bd92de Mon Sep 17 00:00:00 2001
From: Andrea Corallo <akrl@sdf.org>
Date: Sun, 13 Oct 2019 20:22:14 +0200
Subject: [PATCH] add stack sanity check

---
 lisp/emacs-lisp/comp.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index b2eee68b3ff..adda0537a6e 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -745,7 +745,8 @@ the annotation emission."
                (cdr insn))))
     (comp-op-case
       (TAG
-       (comp-lap-to-limple-bb arg))
+       ;; Paranoically sanity check stack depth.
+       (cl-assert (= (cddr insn) (comp-limplify-sp comp-pass))))
       (byte-stack-ref
        (comp-copy-slot (- (comp-sp) arg 1)))
       (byte-varref
-- 
2.39.5