Subject: bug#35770: [PATCH] Broken duplicate case elimination in switch byte-compilation

From: Mattias Engdegård <[email-masked]>
Date: Sun, 26 May 2019 19:05:55 +0200

22 maj 2019 kl. 16.19 skrev Stefan Monnier <[email-masked]>:
> 
> turning off byte-compile-cond-use-jump-table by default is the safer way
> to do that, I think.

Is the consensus then that the patch is fine for master, and that the switch op generation should be disabled by default in emacs-26? Maybe with an explanation in the doc string:

-(defcustom byte-compile-cond-use-jump-table t
-  "Compile `cond' clauses to a jump table implementation (using a hash-table)."
+(defcustom byte-compile-cond-use-jump-table nil
+  "Compile `cond' clauses to a jump table implementation (using a hash-table).
+
+In Emacs 26, this feature is disabled by default because of a bug
+in the code generation of `cond' forms with duplicated test clauses."
   :version "26.1"
   :group 'bytecomp
   :type 'boolean)

If so, I'll push. No NEWS change needed in either branch, right?