diff --git a/src/compiler/alpha/cell.lisp b/src/compiler/alpha/cell.lisp
index 46af433363..b199563b2b 100644
--- a/src/compiler/alpha/cell.lisp
+++ b/src/compiler/alpha/cell.lisp
@@ -36,7 +36,9 @@
     #!-gengc
     (storew value object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 ;;;; symbol hacking VOPs
 
diff --git a/src/compiler/arm/cell.lisp b/src/compiler/arm/cell.lisp
index cbde25c471..f22aa9a48a 100644
--- a/src/compiler/arm/cell.lisp
+++ b/src/compiler/arm/cell.lisp
@@ -31,7 +31,9 @@
   (:generator 1
     (storew value object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 ;;;; Symbol hacking VOPs:
 
diff --git a/src/compiler/arm64/cell.lisp b/src/compiler/arm64/cell.lisp
index 8b811f13dd..ac939d5c4e 100644
--- a/src/compiler/arm64/cell.lisp
+++ b/src/compiler/arm64/cell.lisp
@@ -31,7 +31,9 @@
   (:generator 1
     (storew value object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 (define-vop (compare-and-swap-slot)
   (:args (object :scs (descriptor-reg))
diff --git a/src/compiler/generic/vm-ir2tran.lisp b/src/compiler/generic/vm-ir2tran.lisp
index 6a1b7c1e5e..311d31ed8d 100644
--- a/src/compiler/generic/vm-ir2tran.lisp
+++ b/src/compiler/generic/vm-ir2tran.lisp
@@ -99,7 +99,7 @@
                          `(ecase raw-type
                             ((t)
                              (vop init-slot node block object arg-tn
-                                  name (+ sb!vm:instance-slots-offset slot) lowtag))
+                                  name dx-p (+ sb!vm:instance-slots-offset slot) lowtag))
                             ,@(map 'list
                                (lambda (rsd)
                                  `(,(sb!kernel::raw-slot-data-raw-type rsd)
@@ -111,7 +111,7 @@
            (:dd
             (vop init-slot node block object
                  (emit-constant (sb!kernel::dd-layout-or-lose slot))
-                 name
+                 name dx-p
                  ;; Layout has no index if compact headers.
                  (or #!+compact-instance-header :layout sb!vm:instance-slots-offset)
                  lowtag))
@@ -148,7 +148,7 @@
                                              (sc-number-or-lose 'sb!vm::any-reg))))
                                     (vop make-funcallable-instance-tramp node block tn)
                                     tn)))))
-                     name slot lowtag))))))))
+                     name dx-p slot lowtag))))))))
   (unless (null args)
     (bug "Leftover args: ~S" args)))
 
diff --git a/src/compiler/hppa/cell.lisp b/src/compiler/hppa/cell.lisp
index 747cf18c7e..1c2f377d6b 100644
--- a/src/compiler/hppa/cell.lisp
+++ b/src/compiler/hppa/cell.lisp
@@ -31,7 +31,9 @@
   (:generator 1
     (storew value object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 ;;;; Symbol hacking VOPs:
 
diff --git a/src/compiler/mips/cell.lisp b/src/compiler/mips/cell.lisp
index a91790810f..02ad1a845b 100644
--- a/src/compiler/mips/cell.lisp
+++ b/src/compiler/mips/cell.lisp
@@ -31,7 +31,9 @@
   (:generator 1
     (storew value object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 ;;;; Symbol hacking VOPs:
 
diff --git a/src/compiler/ppc/cell.lisp b/src/compiler/ppc/cell.lisp
index 1146ad3bac..971ed48a08 100644
--- a/src/compiler/ppc/cell.lisp
+++ b/src/compiler/ppc/cell.lisp
@@ -31,7 +31,9 @@
   (:generator 1
     (storew value object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 #!+compare-and-swap-vops
 (define-vop (compare-and-swap-slot)
diff --git a/src/compiler/sparc/cell.lisp b/src/compiler/sparc/cell.lisp
index 98dc820078..0d9b1f1157 100644
--- a/src/compiler/sparc/cell.lisp
+++ b/src/compiler/sparc/cell.lisp
@@ -30,7 +30,9 @@
   (:generator 1
     (storew value object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 ;;;; Symbol hacking VOPs:
 
diff --git a/src/compiler/x86-64/cell.lisp b/src/compiler/x86-64/cell.lisp
index 3961dc264c..439d8e0d19 100644
--- a/src/compiler/x86-64/cell.lisp
+++ b/src/compiler/x86-64/cell.lisp
@@ -45,8 +45,9 @@
 
 ;; INIT-SLOT has to know about the :COMPACT-INSTANCE-HEADER feature.
 (define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
   (:generator 1
-    (progn name)
+    (progn name dx-p)
     (if (or #!+compact-instance-header
             (and (eq name '%make-structure-instance) (eql offset :layout)))
         ;; The layout is in the upper half of the header word.
diff --git a/src/compiler/x86/cell.lisp b/src/compiler/x86/cell.lisp
index 14dc4a5380..66b2be70a3 100644
--- a/src/compiler/x86/cell.lisp
+++ b/src/compiler/x86/cell.lisp
@@ -30,7 +30,9 @@
   (:generator 1
      (storew (encode-value-if-immediate value) object offset lowtag)))
 
-(define-vop (init-slot set-slot))
+(define-vop (init-slot set-slot)
+  (:info name dx-p offset lowtag)
+  (:ignore name dx-p))
 
 (define-vop (compare-and-swap-slot)
   (:args (object :scs (descriptor-reg) :to :eval)