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Clean up and improve compilation of arithmetic (bug#42597)

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* 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.
This commit is contained in:
Mattias Engdegård 2020-08-03 16:29:06 +02:00
parent 204273c3b9
commit 0facaeec1a
2 changed files with 62 additions and 60 deletions
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29
lisp/emacs-lisp/byte-opt.el
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@ -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)