From 24641e414030efb2eabff80ab15dbd1e1fae929a Mon Sep 17 00:00:00 2001
From: Stas Boukarev <stassats@gmail.com>
Date: Mon, 15 Jan 2018 21:03:46 +0300
Subject: [PATCH] Protect unconvert-tail-calls against deleted blocks.

Fixes lp#1742190.
---
 src/compiler/locall.lisp   | 1 +
 tests/compiler-2.pure.lisp | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/src/compiler/locall.lisp b/src/compiler/locall.lisp
index 46bc995b8..41985f203 100644
--- a/src/compiler/locall.lisp
+++ b/src/compiler/locall.lisp
@@ -1039,6 +1039,7 @@
         (let ((this-call (node-dest ref)))
           (when (and this-call
                      (node-tail-p this-call)
+                     (not (node-to-be-deleted-p this-call))
                      (eq (node-home-lambda this-call) fun))
             (setf (node-tail-p this-call) nil)
             (ecase (functional-kind called)
diff --git a/tests/compiler-2.pure.lisp b/tests/compiler-2.pure.lisp
index fa8fecf29..27a1d74f6 100644
--- a/tests/compiler-2.pure.lisp
+++ b/tests/compiler-2.pure.lisp
@@ -1030,3 +1030,12 @@
                       `(lambda ()
                          (handler-case (declare)))
                       :allow-failure t))))
+
+(with-test (:name (:unconvert-tail-calls :deleted-call))
+  (assert (nth-value 1
+                     (checked-compile
+                      '(lambda ()
+                        (labels ((%f (&optional (x (* 2 nil (%f)))) x))
+                          (%f)
+                          (%f 1)))
+                      :allow-warnings t))))
-- 
2.11.4.GIT