When I apply this to head master:

diff --git a/module/language/cps/simplify.scm b/module/language/cps/simpl
ify.scm
index 311566043..b6fcffcd1 100644
--- a/module/language/cps/simplify.scm
+++ b/module/language/cps/simplify.scm
@@ -149,6 +149,9 @@
              (($ $kargs names syms ($ $branch kf kt src op param args))
               ($kargs names syms
                 ($branch (subst kf) (subst kt) src op param args)))
+              (($ $kargs names syms ($ $prompt k kh src escape? tag))
+               ($kargs names syms
+                 ($prompt (subst k) (subst kh) src escape? tag)))
              (($ $kargs names syms ($ $continue k src ($ $const val)))
               ,(match (intmap-ref conts k)
                  (($ $kargs (_)

Things compiles just fine

Regards
Stefan