bug#38708: [PATCH] Deduplicate flonum and bignum constants in bytecode

["Mattias Engdegård" <mattiase@acm.org>]

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Minor improvement to avoid duplication of some numbers in bytecode.

No significant degradation in compilation speed observed. The savings aren't huge either: 1382 bytes in all .elc files, but the in-memory savings are probably higher, since an extra small flonum (1.0, say) only costs 4 bytes in the .elc file, but something like 16-24 bytes in memory (pointer + boxed flonum).


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From 9c2b6e940d9fd6db189c52b92c60ed3a3fb7dfd4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Sun, 22 Dec 2019 12:09:06 +0100
Subject: [PATCH] Deduplicate non-fixnum numeric constants in byte-compilation

* lisp/emacs-lisp/bytecomp.el (byte-compile-get-constant):
Use eql for looking up constants instead of eq, allowing
for bignum and flonum deduplication.
---
 lisp/emacs-lisp/bytecomp.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 118356ec26..60dbae1d4b 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -3462,7 +3462,7 @@ byte-compile-get-constant
 	       (if (equal-including-properties (car elt) ,const)
 		   (setq result elt)))
 	     result)
-	 (assq ,const byte-compile-constants))
+	 (assoc ,const byte-compile-constants #'eql))
        (car (setq byte-compile-constants
 		  (cons (list ,const) byte-compile-constants)))))
 
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