tweak tail merging logic

[sbcl.git] / src / compiler / ir1util.lisp

diff --git a/src/compiler/ir1util.lisp b/src/compiler/ir1util.lisp
index e3ef6cf..4f433b1 100644 (file)
--- a/src/compiler/ir1util.lisp
+++ b/src/compiler/ir1util.lisp
@@ -149,6 +149,16 @@
            (t (eq (block-start (first (block-succ (node-block node))))
                   (node-prev dest))))))
 
+;;; Returns the defined (usually untrusted) type of the combination,
+;;; or NIL if we couldn't figure it out.
+(defun combination-defined-type (combination)
+  (let ((use (principal-lvar-use (basic-combination-fun combination))))
+    (or (when (ref-p use)
+          (let ((type (leaf-defined-type (ref-leaf use))))
+            (when (fun-type-p type)
+              (fun-type-returns type))))
+        *wild-type*)))
+
 ;;; Return true if LVAR destination is executed after node with only
 ;;; uninteresting nodes intervening.
 ;;;