From 7e2689debbaf40c77ae572849b73e3821efb25da Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 27 Mar 2018 21:38:06 -0700
Subject: compiler: don't wastefully enter into dreg table.

* share/txr/stdlib/compiler.tl (compiler get-dreg): If the
input atom is nil, return the t0 register that always
holds nil.
---
 share/txr/stdlib/compiler.tl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/share/txr/stdlib/compiler.tl b/share/txr/stdlib/compiler.tl
index d77c4cd1..6a778ed7 100644
--- a/share/txr/stdlib/compiler.tl
+++ b/share/txr/stdlib/compiler.tl
@@ -122,6 +122,7 @@
 
 (defmeth compiler get-dreg (me atom)
   (condlet
+    ((((null atom))) '(t 0))
     (((dreg [me.dreg atom])) dreg)
     ((((< me.dreg-cntr 256)))
      (let* ((dreg ^(d ,(pinc me.dreg-cntr))))
-- 
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