From: Guillermo J. Rozas <edu/mit/csail/zurich/gjr>
Date: Sun, 6 Nov 1988 13:55:39 +0000 (+0000)
Subject: An lvalue whose only backward link is itself may be known.
X-Git-Tag: 20090517-FFI~12431
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=75902f99fbe3998096784e869357c6f3215914de;p=mit-scheme.git

An lvalue whose only backward link is itself may be known.
This is a patch. General loops should work as well.
---

diff --git a/v7/src/compiler/fgopt/folcon.scm b/v7/src/compiler/fgopt/folcon.scm
index 813c924b7..e86bb5487 100644
--- a/v7/src/compiler/fgopt/folcon.scm
+++ b/v7/src/compiler/fgopt/folcon.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/fgopt/folcon.scm,v 4.2 1987/12/30 06:44:31 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/fgopt/folcon.scm,v 4.3 1988/11/06 13:55:39 jinx Exp $
 
 Copyright (c) 1987 Massachusetts Institute of Technology
 
@@ -75,7 +75,11 @@ MIT in each case. |#
 
 (define (delete-if-known! lvalue)
   (if (and (not (lvalue-known-value lvalue))
-	   (for-all? (lvalue-backward-links lvalue) lvalue-known-value))
+	   (for-all? (lvalue-backward-links lvalue)
+	     (lambda (lvalue*)
+	       (if (eq? lvalue lvalue*)
+		   true
+		   (lvalue-known-value lvalue*)))))
       (let ((value (car (lvalue-values lvalue))))
 	(for-each (lambda (lvalue*)
 		    (if (lvalue-mark-set? lvalue* 'KNOWABLE)