Add function for replacing IR-TERMINATOR in IBLOCK

user-side-compiler/middle/graph-manipulation.lisp

@@ -24,6 +24,17 @@
         (setf (start ib) new)
         (setf (next prev-inst) new))))
 
+(defun replace-terminator (old new)
+  (check-type old ir-terminator)
+  (check-type new ir-terminator)
+  (let ((iblock (iblock old))
+        (before (previous old)))
+    (setf (destinations old) '()
+          (next before) new
+          (end iblock) new
+          (iblock new) iblock
+          (previous new) before)))
+
 (defun yank-instruction (instruction)
   "Removes INSTRUCTIONS without cleaning up, allowing it to be put back in."
   (check-type instruction (and ir-inst (not ir-terminator)))