Hi all, I had a look at #1620 and as far as I can tell there's no reason why an aliased variable cannot be marked as replaceable when either the alias or the variable it aliases are captured.
Captured simply means that it needs to be wrapped up in the closure, AFAIK. But if it's replaced, then the original variable will need to end up in the closure. The only case where you can't replace is if either variable is assigned to, because then they don't point to the same thing anymore. I've tested several eggs with this and it seems to work fine. The test case in #1620 is now compiled similar to the version with manually inserted eq? calls. I checked the benchmarks. It doesn't have much of an effect on most benchmarks, but gold and gold2 are consistently about 15% faster with the new version; I did a quick check and it seems there are indeed several places which look like let calls which get replaced properly. Cheers, Peter
From 3f6a497a6227b139bea6f2f5ca5fc192161b6ae6 Mon Sep 17 00:00:00 2001 From: Peter Bex <pe...@more-magic.net> Date: Sun, 30 Jun 2019 15:42:19 +0200 Subject: [PATCH] Mark aliased variable as replacable even if either variable is captured The only thing that really matters is whether it is global or assigned to, the capture state is irrelevant as far as I can tell. Fixes #1620 --- core.scm | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) diff --git a/core.scm b/core.scm index c659691d..dcfec05c 100644 --- a/core.scm +++ b/core.scm @@ -2317,11 +2317,9 @@ (quick-put! plist 'inlinable #t) (quick-put! plist 'local-value n)))))))) - ;; Make 'collapsable, if it has a known constant value which is either collapsable or is only - ;; referenced once and if no assignments are made: - (when (and value - ;; (not (assq 'assigned plist)) - If it has a known value, it's assigned just once! - (eq? 'quote (node-class value)) ) + ;; Make 'collapsable, if it has a known constant value which + ;; is either collapsable or is only referenced once: + (when (and value (eq? 'quote (node-class value)) ) (let ((val (first (node-parameters value)))) (when (or (collapsable-literal? val) (= 1 nreferences) ) @@ -2372,23 +2370,19 @@ (quick-put! plist 'removable #t) ) ;; Make 'replacable, if it has a variable as known value and if either that variable has - ;; a known value itself, or if it is not captured and referenced only once, the target and - ;; the source are never assigned and the source is non-global or we are in block-mode: + ;; a known value itself, or the target and the source are never assigned and the source + ;; is non-global or we are in block-mode: ;; - The target-variable is not allowed to be global. ;; - The variable that can be substituted for the current one is marked as 'replacing. ;; This is done to prohibit beta-contraction of the replacing variable (It wouldn't be there, if ;; it was contracted). (when (and value (not global)) (when (eq? '##core#variable (node-class value)) - (let* ((name (first (node-parameters value))) - (nrefs (db-get db name 'references)) ) + (let ((name (first (node-parameters value))) ) (when (and (not captured) (or (and (not (db-get db name 'unknown)) (db-get db name 'value)) - (and (not (db-get db name 'captured)) - nrefs - (= 1 (length nrefs)) - (not assigned) + (and (not assigned) (not (db-get db name 'assigned)) (or (not (variable-visible? name block-compilation)) -- 2.11.0
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