master 1ba5b64: Optimise 'while' bodies for effect

[Mattias Engdegård]

branch: master
commit 1ba5b64dd1f0c0b22f3945ddc8b236fd565ebee8
Author: Mattias Engdegård <address@hidden>
Commit: Mattias Engdegård <address@hidden>

    Optimise 'while' bodies for effect
    
    * lisp/emacs-lisp/byte-opt.el (byte-optimize-form-code-walker):
    Treat all expressions in the body of 'while' as for-effect,
    since their values are discarded.  This also finds some errors.
---
 lisp/emacs-lisp/byte-opt.el | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index 22fea1b..07fd548 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -480,6 +480,13 @@
                                                  backwards)))))
             (cons fn (mapcar 'byte-optimize-form (cdr form)))))
 
+         ((eq fn 'while)
+           (unless (consp (cdr form))
+            (byte-compile-warn "too few arguments for `while'"))
+           (cons fn
+                 (cons (byte-optimize-form (cadr form) nil)
+                       (byte-optimize-body (cddr form) t))))
+
          ((eq fn 'interactive)
           (byte-compile-warn "misplaced interactive spec: `%s'"
                              (prin1-to-string form))