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Generalise a LAP optimisation rule

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* lisp/emacs-lisp/byte-opt.el (byte-optimize-lapcode):
Accept (stack-set 1) as equivalent to (discardN-preserve-tos 1) in a
rule previously overlooked.  This is usually beneficial in code size
and almost always shortens dynamic paths.
This commit is contained in:
Mattias Engdegård 2023-03-25 15:38:00 +01:00
parent db7e95531a
commit 52b67740d1
1 changed files with 3 additions and 1 deletions
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lisp/emacs-lisp/byte-opt.el
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@ -2765,7 +2765,9 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance."
(or (memq (caar tmp) '(byte-discard byte-discardN))
;; Make sure we don't hoist a discardN-preserve-tos
;; that really should be merged or deleted instead.
(and (eq (caar tmp) 'byte-discardN-preserve-tos)
(and (or (eq (caar tmp) 'byte-discardN-preserve-tos)
(and (eq (caar tmp) 'byte-stack-set)
(eql (cdar tmp) 1)))
(let ((next (cadr tmp)))
(not (or (memq (car next)
'(byte-discardN-preserve-tos