master: Don't dx the list in (dx-let ((a (list a b))) (reverse a))

The branch "master" has been updated in SBCL:
       via  d1b2b076bc95d36d046bd8cadcecc7506e4204bc (commit)
      from  913710ac98e1e1ad738d1dabd02015296a629c7d (commit)

- Log -----------------------------------------------------------------
commit d1b2b076bc95d36d046bd8cadcecc7506e4204bc
Author: Stas Boukarev <[email protected]>
Date:   Sun Aug 30 01:58:54 2026 +0300

    Don't dx the list in (dx-let ((a (list a b))) (reverse a))
---
 src/compiler/ir1util.lisp      | 14 ++++++++++----
 src/compiler/seqtran.lisp      |  4 ++++
 tests/dynamic-extent.pure.lisp |  9 +++++++++
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/compiler/ir1util.lisp b/src/compiler/ir1util.lisp
index f9e2b381c..33649646f 100644
--- a/src/compiler/ir1util.lisp
+++ b/src/compiler/ir1util.lisp
@@ -1060,12 +1060,18 @@
 
   (values))
 
+(defun remove-lvar-dx (lvar)
+  (when lvar
+    (let ((dynamic-extent (lvar-dynamic-extent lvar)))
+      (when dynamic-extent
+        (setf (lvar-dynamic-extent lvar) nil)
+        (setf (dynamic-extent-values dynamic-extent)
+              (delq1 lvar (dynamic-extent-values dynamic-extent)))
+        dynamic-extent))))
+
 (defun propagate-lvar-dx (new old)
-  (let ((dynamic-extent (lvar-dynamic-extent old)))
+  (let ((dynamic-extent (remove-lvar-dx old)))
     (when dynamic-extent
-      (setf (lvar-dynamic-extent old) nil)
-      (setf (dynamic-extent-values dynamic-extent)
-            (delq1 old (dynamic-extent-values dynamic-extent)))
       (unless (lvar-dynamic-extent new)
         (setf (lvar-dynamic-extent new) dynamic-extent)
         (push new (dynamic-extent-values dynamic-extent))))))
diff --git a/src/compiler/seqtran.lisp b/src/compiler/seqtran.lisp
index 4643dd2d7..77de1550e 100644
--- a/src/compiler/seqtran.lisp
+++ b/src/compiler/seqtran.lisp
@@ -4209,15 +4209,18 @@
   (or (combination-case sequence
         (list *
          (setf (combination-args combination) (reverse args))
+         (remove-lvar-dx sequence)
          'sequence)
         (list* *
          (let ((last (last args)))
            (cond ((lvar-subtypep (car last) null)
                   (setf (combination-args combination)
                         (append (cdr (reverse args)) last))
+                  (remove-lvar-dx sequence)
                   'sequence)
                  (t
                   (splice-fun-args sequence 'list* nil)
+                  (remove-lvar-dx sequence)
                   (let ((vars (make-gensym-list (length args))))
                     `(lambda ,vars
                        (,(case (combination-name node)
@@ -4227,6 +4230,7 @@
                         (list ,@(reverse (butlast vars))))))))))
         (initialize-vector *
          (setf (combination-args combination) (reverse args))
+         (remove-lvar-dx sequence)
          'sequence))
       (give-up-ir1-transform)))
 
diff --git a/tests/dynamic-extent.pure.lisp b/tests/dynamic-extent.pure.lisp
index e1178fb98..a0e07d389 100644
--- a/tests/dynamic-extent.pure.lisp
+++ b/tests/dynamic-extent.pure.lisp
@@ -2636,3 +2636,12 @@
                                          (declare (notinline f))
                                          (f (lambda () x)))))
                    1)))
+
+(with-test (:name :reverse-remove-dx)
+  (declare (optimize (debug 1)))
+  (checked-compile-and-assert
+   ()
+   `(lambda (a b)
+      (sb-int:dx-let ((a (list a b)))
+        (stack-allocated-p (reverse a))))
+   ((1 2) nil)))

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