From d066056a22bfea38901da258bd039fc4588c8251 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Wed, 25 Oct 2017 23:52:33 -0700
Subject: awk: retrieve range flag vector once per iteration.

This is an improvement in the code generation related
to awk range expressions. Previously, on each iteration,
for each range expression, the awk state structure is
accessed to retrieve the flag vector, which is then kept
in a lexical variable. With this change, the retrieval
is done once for all the range expressions, which share
the same variable to access it.

* share/txr/stdlib/awk.tl (sys:awk-compile-time): New slot,
rng-vec-temp.
(sys:awk-mac-let): Alias the flag variable to a simplified
vecref expression which accesses the vector assumed to
have been retrieved and bound to the variable named by
the rng-vec-temp gensym.
(awk): Add one more variable binding into the scope of
the ranges: the binding of the variable named by the
rng-vec-temp gensym, to an expression which retrieves the
rng-vec from the Awk run-time state structure.
---
 share/txr/stdlib/awk.tl | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/share/txr/stdlib/awk.tl b/share/txr/stdlib/awk.tl
index 57e7c271..88509ccd 100644
--- a/share/txr/stdlib/awk.tl
+++ b/share/txr/stdlib/awk.tl
@@ -61,6 +61,7 @@
   cond-actions
   (nranges 0)
   (rng-rec-temp (gensym))
+  (rng-vec-temp (gensym))
   rng-expr-temps
   rng-exprs
   outer-env)
@@ -334,7 +335,7 @@
                                                (set-diff te-ef te-ff)
                                                'functions)
                       (push rng-temp (qref ,awc rng-expr-temps))
-                      (push ^(placelet ((flag (vecref (qref ,',aws-sym rng-vec) ,ix)))
+                      (push ^(placelet ((flag (vecref ,(qref ,awc rng-vec-temp) ,ix)))
                                (let ((,flag-old flag) ,flag-act ,flag-deact
                                      ,*(if need-mid ^(,flag-mid (,from-expr-val ,from-expr-ex))))
                                  ,*(if need-mid
@@ -474,9 +475,10 @@
                             ^((,awk-fun (lambda (,aws-sym)
                                           ,(if awc.rng-exprs
                                              ^(let* ((,awc.rng-rec-temp rec)
-                                                 ,*(nreverse
-                                                     (zip awc.rng-expr-temps
-                                                          awc.rng-exprs)))
+                                                     (,awc.rng-vec-temp (qref ,aws-sym rng-vec))
+                                                     ,*(nreverse
+                                                         (zip awc.rng-expr-temps
+                                                              awc.rng-exprs)))
                                                 ,p-actions-xform)
                                              p-actions-xform))))))
                    ,*awc.begin-actions
-- 
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