From: Mattias Engdegård <mattiase@acm.org>
Date: Tue, 2 Nov 2021 13:48:55 +0000 (+0100)
Subject: Optimise (cond) => nil at source level
X-Git-Tag: emacs-29.0.90~3671^2~280
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=493fde95bed6c65e049b8e664837397546847b37;p=emacs.git

Optimise (cond) => nil at source level

* lisp/emacs-lisp/byte-opt.el (byte-optimize-cond):
Optimise clause-free `cond`, which can arise from earlier
transformations.  This enables further optimisations.
* test/lisp/emacs-lisp/bytecomp-tests.el (bytecomp-tests--test-cases):
Add test cases.
---

diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index 9b3b2e5ce14..9c64083b64b 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -1327,7 +1327,7 @@ See Info node `(elisp) Integer Basics'."
 	    (list 'or (car (car clauses))
 		  (byte-optimize-cond
 		   (cons (car form) (cdr (cdr form)))))
-	  form))
+	  (and clauses form)))
     form))
 
 (defun byte-optimize-if (form)
diff --git a/test/lisp/emacs-lisp/bytecomp-tests.el b/test/lisp/emacs-lisp/bytecomp-tests.el
index a6e224b3d2c..41edc1f8289 100644
--- a/test/lisp/emacs-lisp/bytecomp-tests.el
+++ b/test/lisp/emacs-lisp/bytecomp-tests.el
@@ -640,6 +640,9 @@ inner loops respectively."
            (f (list (lambda (x) (setq a x)))))
       (funcall (car f) 3)
       (list a b))
+
+    (cond)
+    (mapcar (lambda (x) (cond ((= x 0)))) '(0 1))
     )
   "List of expressions for cross-testing interpreted and compiled code.")