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* Optimize optimizable variables

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* lisp/emacs-lisp/comp.el (comp-symbol-values-optimizable): New
	defconst.
	(comp-function-call-maybe-remove): New logic to to remove
	unnecessary `symbol-value' calls.
This commit is contained in:
Andrea Corallo 2020-06-07 00:34:21 +02:00
parent 489a79de96
commit a58fef9f63
1 changed files with 26 additions and 11 deletions
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37
lisp/emacs-lisp/comp.el
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@ -184,6 +184,10 @@ Can be one of: 'd-default', 'd-impure' or 'd-ephemeral'. See `comp-ctxt'.")
(comp-hint-cons . cons))
"Alist used for type propagation.")
(defconst comp-symbol-values-optimizable '(most-positive-fixnum
most-negative-fixnum)
"Symbol values we can resolve in the compile-time.")
(defconst comp-type-hints '(comp-hint-fixnum
comp-hint-cons)
"List of fake functions used to give compiler hints.")
@ -1883,17 +1887,28 @@ Here goes everything that can be done not iteratively (read once).
(defsubst comp-function-call-maybe-remove (insn f args)
"Given INSN when F is pure if all ARGS are known remove the function call."
(when (comp-function-optimizable f args)
(ignore-errors
;; No point to complain here because we should do basic block
;; pruning in order to be sure that this is not dead-code. This
;; is now left to gcc, to be implemented only if we want a
;; reliable diagnostic here.
(let ((value (apply f (mapcar #'comp-mvar-constant args))))
;; See `comp-emit-setimm'.
(comp-add-const-to-relocs value)
(setf (car insn) 'setimm
(cddr insn) `(,value))))))
(cl-flet ((rewrite-insn-as-setimm (insn value)
;; See `comp-emit-setimm'.
(comp-add-const-to-relocs value)
(setf (car insn) 'setimm
(cddr insn) `(,value))))
(cond
((eq f 'symbol-value)
(when-let* ((arg0 (car args))
(const (comp-mvar-const-vld arg0))
(ok-to-optim (member (comp-mvar-constant arg0)
comp-symbol-values-optimizable)))
(rewrite-insn-as-setimm insn (symbol-value (comp-mvar-constant
(car args))))))
((comp-function-optimizable f args)
(ignore-errors
;; No point to complain here because we should do basic block
;; pruning in order to be sure that this is not dead-code. This
;; is now left to gcc, to be implemented only if we want a
;; reliable diagnostic here.
(rewrite-insn-as-setimm insn
(apply f
(mapcar #'comp-mvar-constant args))))))))
(defun comp-propagate-insn (insn)
"Propagate within INSN."