From 0facaeec1a37481536b6cef13c88d9728c2ec29b Mon Sep 17 00:00:00 2001 From: Mattias Engdegård Date: Mon, 3 Aug 2020 16:29:06 +0200 Subject: Clean up and improve compilation of arithmetic (bug#42597) * lisp/emacs-lisp/byte-opt.el (byte-optimize-associative-math) (byte-optimize-min-max): Transform 3-arg min/max call into two 2-arg calls, which is faster. * lisp/emacs-lisp/bytecomp.el (byte-compile-associative): Rename to... (byte-compile-variadic-numeric): ...this function and simplify, fixing incorrect comments. The 3-arg strength reduction is now always done in the optimisers and is no longer needed here. (byte-compile-min-max): New function. (byte-compile-minus): Simplify, remove incorrect comment, and use byte-compile-variadic-numeric. (byte-compile-quo): Simplify and fix comment. --- lisp/emacs-lisp/byte-opt.el | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) (limited to 'lisp/emacs-lisp/byte-opt.el') diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el index 0d9c449b3b4..4987596bf95 100644 --- a/lisp/emacs-lisp/byte-opt.el +++ b/lisp/emacs-lisp/byte-opt.el @@ -648,14 +648,23 @@ (setq args (cons (car rest) args))) (setq rest (cdr rest))) (if (cdr constants) - (if args - (list (car form) - (apply (car form) constants) - (if (cdr args) - (cons (car form) (nreverse args)) - (car args))) - (apply (car form) constants)) - form))) + (let ((const (apply (car form) (nreverse constants)))) + (if args + (append (list (car form) const) + (nreverse args)) + const)) + form))) + +(defun byte-optimize-min-max (form) + "Optimize `min' and `max'." + (let ((opt (byte-optimize-associative-math form))) + (if (and (consp opt) (memq (car opt) '(min max)) + (= (length opt) 4)) + ;; (OP x y z) -> (OP (OP x y) z), in order to use binary byte ops. + (list (car opt) + (list (car opt) (nth 1 opt) (nth 2 opt)) + (nth 3 opt)) + opt))) ;; Use OP to reduce any leading prefix of constant numbers in the list ;; (cons ACCUM ARGS) down to a single number, and return the @@ -878,8 +887,8 @@ (put '* 'byte-optimizer #'byte-optimize-multiply) (put '- 'byte-optimizer #'byte-optimize-minus) (put '/ 'byte-optimizer #'byte-optimize-divide) -(put 'max 'byte-optimizer #'byte-optimize-associative-math) -(put 'min 'byte-optimizer #'byte-optimize-associative-math) +(put 'max 'byte-optimizer #'byte-optimize-min-max) +(put 'min 'byte-optimizer #'byte-optimize-min-max) (put '= 'byte-optimizer #'byte-optimize-binary-predicate) (put 'eq 'byte-optimizer #'byte-optimize-binary-predicate) -- cgit v1.2.3