0.6.11.6:

[sbcl.git] / src / compiler / byte-comp.lisp

diff --git a/src/compiler/byte-comp.lisp b/src/compiler/byte-comp.lisp
index fa70dfd..f8eb793 100644 (file)
--- a/src/compiler/byte-comp.lisp
+++ b/src/compiler/byte-comp.lisp
@@ -1229,8 +1229,8 @@
                      (output-push-constant segment (leaf-name leaf))
                      (output-do-inline-function segment 'symbol-value))))
            (clambda
-            (let* ((refered-env (lambda-environment leaf))
-                   (closure (environment-closure refered-env)))
+            (let* ((referred-env (lambda-environment leaf))
+                   (closure (environment-closure referred-env)))
               (if (null closure)
                   (output-push-load-time-constant segment :entry leaf)
                   (let ((my-env (node-environment ref)))
@@ -1275,18 +1275,20 @@
         ((:special :global)
          (output-push-constant segment (global-var-name leaf))
          (output-do-inline-function segment 'setf-symbol-value))))
-      ;;; MNA: cmucl-commit: Tue, 26 Sep 2000 09:41:00 -0700 (PDT)
-      ;;; Within generate-byte-code-for-set, avoid trying to set a lexical
-      ;;; variable with no refs since the compiler deletes such variables.
       (lambda-var
+       ;; Note: It's important to test for whether there are any
+       ;; references to the variable before we actually try to set it.
+       ;; (Setting a lexical variable with no refs caused bugs ca. CMU
+       ;; CL 18c, because the compiler deletes such variables.)
         (cond ((leaf-refs leaf)
-             (unless (eql values 0)
-               ;; Someone wants the value, so copy it.
-               (output-do-xop segment 'dup))
-             (output-set-lambda-var segment leaf (node-environment set)))
-            ;; If no-one wants the value then pop it else leave it for them.
-            ((eql values 0)
-             (output-byte-with-operand segment byte-pop-n 1)))))
+              (unless (eql values 0)
+                ;; Someone wants the value, so copy it.
+                (output-do-xop segment 'dup))
+              (output-set-lambda-var segment leaf (node-environment set)))
+             ;; If no one wants the value, then pop it, else leave it
+             ;; for them.
+             ((eql values 0)
+              (output-byte-with-operand segment byte-pop-n 1)))))
     (unless (eql values 0)
       (checked-canonicalize-values segment cont 1)))
   (values))