[Guile-commits] 01/02: Eval speedup for lexical-ref

[Andy Wingo]

wingo pushed a commit to branch master
in repository guile.

commit 25738ec35d28437f5703147bc43cf0d45afff964
Author: Andy Wingo <address@hidden>
Date:   Wed Nov 11 14:51:19 2015 +0100

    Eval speedup for lexical-ref
    
    * module/ice-9/eval.scm (primitive-eval): Specialize lexical-ref for
      depths 0, 1, and 2.  Speeds up this test by around 13%:
    
        (primitive-eval '(let lp ((n 0)) (when (< n #e1e7) (lp (1+ n)))))
---
 module/ice-9/eval.scm |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/module/ice-9/eval.scm b/module/ice-9/eval.scm
index 3b68f07..a2bab20 100644
--- a/module/ice-9/eval.scm
+++ b/module/ice-9/eval.scm
@@ -119,8 +119,11 @@
         (proc arg ...))))
 
   (define (compile-lexical-ref depth width)
-    (lambda (env)
-      (env-ref env depth width)))
+    (case depth
+      ((0) (lambda (env) (env-ref env 0 width)))
+      ((1) (lambda (env) (env-ref env 1 width)))
+      ((2) (lambda (env) (env-ref env 2 width)))
+      (else (lambda (env) (env-ref env depth width)))))
 
   (define (primitive=? name loc module var)
     "Return true if VAR is the same as the primitive bound to NAME."