diff --git a/src/sf/subst.scm b/src/sf/subst.scm
index 6fa6ac5..dcea1ed 100644
--- a/src/sf/subst.scm
+++ b/src/sf/subst.scm
@@ -453,15 +453,23 @@ you ask for.
 	 (combination/optimizing-make
 	  expression
 	  block
-	  (if (procedure? operator)
-	      (integrate/procedure-operator operations environment
-					    block operator operands)
-	      (let ((operator
-		     (integrate/expression operations environment operator)))
-		(if (procedure? operator)
+	  (let* ((integrate-procedure
+		  (lambda (operator)
 		    (integrate/procedure-operator operations environment
-						  block operator operands)
-		    operator)))
+						  block operator operands)))
+		 (operator
+		  (if (procedure? operator)
+		      (integrate-procedure operator)
+		      (let ((operator
+			     (integrate/expression operations
+						   environment
+						   operator)))
+			(if (procedure? operator)
+			    (integrate-procedure operator)
+			    operator)))))
+	    (cond ((integrate/compound-operator operator)
+		   => integrate-procedure)
+		  (else operator)))
 	  operands))))
 
 (define (integrate/procedure-operator operations environment
@@ -490,6 +498,88 @@ you ask for.
 	  (else (error "Unknown operation" operation))))
       integration-failure)))
 
+;;; ((begin (frob)
+;;;         (let ((a (foo)) (b (bar)))
+;;;           (declare (zork a))
+;;;           (lambda (zot)
+;;;             ...body...)))
+;;;  (mumble frotz))
+;;; =>
+;;; (let ((zot (mumble frotz)))
+;;;   (frob)
+;;;   (let ((a (foo)) (b (bar)))
+;;;     (declare (zork a))
+;;;     ...body...))
+;;;
+;;; This improves the code generated by CALL-WITH-VALUES and VALUES,
+;;; for which ZOT is RECEIVER and (MUMBLE FROTZ) is the continuation.
+;;; It has the consequence of committing to a particular order of
+;;; evaluation, though, when the operands of the outermost combination
+;;; have side effects.
+
+(define (integrate/compound-operator operator)
+  (define (scan-body body encloser)
+    (if (procedure? body)
+	(procedure-with-body body (encloser (procedure/body body)))
+	(scan-operator body encloser)))
+  (define (scan-operator operator encloser)
+    (cond ((sequence? operator)
+	   (let ((reversed-actions (reverse (sequence/actions operator))))
+	     (scan-body (car reversed-actions)
+			(let ((commands (cdr reversed-actions)))
+			  (lambda (expression)
+			    (encloser
+			     (sequence-with-actions
+			      operator
+			      (reverse (cons expression commands)))))))))
+	  ((combination? operator)
+	   (let ((descend
+		  (lambda (operator*)
+		    (scan-body (procedure/body operator*)
+			       (lambda (body*)
+				 (encloser
+				  (combination-with-operator
+				   operator
+				   (procedure-with-body operator* body*)))))))
+		 (operator* (combination/operator operator)))
+	     (cond ((procedure? operator*) (descend operator*))
+		   ((integrate/compound-operator operator*) => descend)
+		   (else #f))))
+	  ((declaration? operator)
+	   (scan-body (declaration/expression operator)
+		      (lambda (expression)
+			(encloser
+			 (declaration-with-expression operator expression)))))
+	  (else #f)))
+  (scan-operator operator (lambda (body) body)))
+
+(define (combination-with-operator combination operator)
+  (combination/make (combination/scode combination)
+		    (combination/block combination)
+		    operator
+		    (combination/operands combination)))
+
+(define (procedure-with-body procedure body)
+  (procedure/make (procedure/scode procedure)
+		  (procedure/block procedure)
+		  (procedure/name procedure)
+		  (procedure/required procedure)
+		  (procedure/optional procedure)
+		  (procedure/rest procedure)
+		  body))
+
+(define (sequence-with-actions sequence actions)
+  (sequence/make (sequence/scode sequence) actions))
+
+(define (declaration-with-expression declaration expression)
+  (declaration/make (declaration/scode declaration)
+		    (declaration/declarations declaration)
+		    expression))
+
+(define (non-side-effecting? expression)
+  (or (reference? expression)
+      (non-side-effecting-in-sequence? expression)))
+
 (define-method/integrate 'DECLARATION
   (lambda (operations environment declaration)
     (let ((declarations (declaration/declarations declaration))
diff --git a/src/sf/usiexp.scm b/src/sf/usiexp.scm
index 5d50463..d596073 100644
--- a/src/sf/usiexp.scm
+++ b/src/sf/usiexp.scm
@@ -351,7 +351,7 @@ USA.
       (make-combination expr block (ucode-primitive cons)
 			(list (car rest)
 			      (list-expansion-loop #f block (cdr rest))))))
-
+
 (define (values-expansion expr operands if-expanded if-not-expanded block)
   if-not-expanded
   (if-expanded
@@ -373,12 +373,18 @@ USA.
 	   (let ((variable (variable/make&bind! block 'RECEIVER)))
 	     (procedure/make
 	      #f block lambda-tag:unnamed (list variable) '() #f
-	      (combination/make #f
-				block
-				(reference/make #f block variable)
-				(map (lambda (variable)
-				       (reference/make #f block variable))
-				     variables))))))
+	      (declaration/make
+	       #f
+	       ;; The receiver is used only once, and all its operand
+	       ;; expressions are effect-free, so integrating here is
+	       ;; safe.
+	       (declarations/parse block '((INTEGRATE-OPERATOR RECEIVER)))
+	       (combination/make #f
+				 block
+				 (reference/make #f block variable)
+				 (map (lambda (variable)
+					(reference/make #f block variable))
+				      variables)))))))
 	operands)))))
 
 (define (call-with-values-expansion expr operands