From: Andrea Corallo <akrl@sdf.org>
Date: Sun, 8 Sep 2019 19:42:51 +0000 (+0200)
Subject: do not override existing basic blocks when branching backwards!
X-Git-Tag: emacs-28.0.90~2727^2~1188
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=c702e25a7a9e1ba2b75942dcc00402947757786d;p=emacs.git

do not override existing basic blocks when branching backwards!
---

diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index 0770d32f7a1..c398810186d 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -500,9 +500,11 @@ If NEGATED non nil negate the tested condition."
       (comp-emit (if negated
 		     (list 'cond-jump a b target bb)
 		   (list 'cond-jump a b bb target)))
-      (puthash target
-	       (make-comp-block :sp (+ target-offset (comp-sp)))
-	       blocks)
+      (unless (gethash target blocks)
+        ;; Create the bb target only if does not exixsts already.
+        (puthash target
+	         (make-comp-block :sp (+ target-offset (comp-sp)))
+	         blocks))
       (comp-mark-block-closed))
     (comp-emit-block bb)))