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Extend propagation to a wider set of (non pure) functions

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This commit is contained in:
Andrea Corallo 2020-01-20 21:16:10 +00:00
parent fce1333c22
commit 9e08edf98f
1 changed files with 30 additions and 4 deletions
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34
lisp/emacs-lisp/comp.el
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@ -1529,6 +1529,17 @@ PRE-LAMBDA and POST-LAMBDA are called in pre or post-order if non nil."
;; This is also responsible for removing function calls to pure functions if
;; possible.
(defvar comp-propagate-classes '(byte-optimize-associative-math
byte-optimize-binary-predicate
byte-optimize-concat
byte-optimize-equal
byte-optimize-identity
byte-optimize-member
byte-optimize-memq
byte-optimize-predicate)
"We optimize functions with 'byte-optimizer' property set to
one of these symbols. See byte-opt.el.")
(defsubst comp-strict-type-of (obj)
"Given OBJ return its type understanding fixnums."
;; Should be certainly smarter but now we take advantages just from fixnums.
@ -1572,19 +1583,34 @@ This can run just once."
(comp-mvar-constant lval) (comp-mvar-constant rval)
(comp-mvar-type lval) (comp-mvar-type rval)))
;; Here should fall most of (defun byte-optimize-* equivalents.
(defsubst comp-function-optimizable (f args)
"Given function F called with ARGS return non nil when optimizable."
(when (cl-every #'comp-mvar-const-vld args)
(or (get f 'pure)
(memq (get f 'byte-optimizer) comp-propagate-classes)
(let ((values (mapcar #'comp-mvar-constant args)))
(pcase f
;; Simple integer operation.
;; Note: byte-opt uses `byte-opt--portable-numberp'
;; instead of just`fixnump'.
((or '+ '- '* '1+ '-1) (and (cl-every #'fixnump values)
(fixnump (apply f values))))
('/ (and (cl-every #'fixnump values)
(not (= (car (last values)) 0)))))))))
(defsubst comp-function-call-remove (insn f args)
"Given INSN when F is pure if all ARGS are known remove the function call."
(when (and (get f 'pure) ; Can we just optimize pure here? See byte-opt.el
(cl-every #'comp-mvar-const-vld args))
(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 ((val (apply f (mapcar #'comp-mvar-constant args))))
(let ((values (apply f (mapcar #'comp-mvar-constant args))))
;; See `comp-emit-set-const'.
(setf (car insn) 'setimm
(cddr insn) (list (comp-add-const-to-relocs val) val))))))
(cddr insn) (list (comp-add-const-to-relocs values) values))))))
(defun comp-propagate-insn (insn)
"Propagate within INSN."