cp0: don't drop 'ignored if with multiple values

Closes racket/racket#3092

original commit: 9e928cf79caf536744491e6889e5c71bcd14c264

mats/cp0.ms

@@ -369,6 +369,14 @@
             (y))))
   (error? (apply zero? 0))
   (error? (if (apply eof-object 1 2) 3 4))
+
+  (equivalent-expansion?
+   (expand/optimize '(lambda (t) (#3%$value (if t 1 (values 3 3 3))) #t))
+   (if (eqv? (optimize-level) 3)
+       '(lambda (x) #t)
+       '(lambda (x)
+          (#3%$value (if x 1 (#2%values 3 3 3)))
+          #t)))
 )
 
 (cp0-mat cp0-mrvs

s/cp0.ss

@@ -662,7 +662,7 @@
                     (let ((opnd (car unused)))
                       (let ((e (operand-value opnd)))
                         (if e
-                            (if (simple? e)
+                            (if (simple1? e)
                                 (if (operand-singly-referenced-score opnd)
                                     ; singly-referenced integration attempt in copy2 succeeded
                                     (f (cdr unused) (fx+ (operand-singly-referenced-score opnd) n) todo)
@@ -2007,8 +2007,12 @@
     (define record-equal?
       ; not very ambitious
       (lambda (e1 e2 ctxt)
-        (if (unused-value-context? ctxt)
-            (and (simple? e1) (simple? e2))
+        (cond
+          [(eq? ctxt 'effect)
+           (and (simple? e1) (simple? e2))]
+          [(eq? ctxt 'ignored)
+           (and (simple1? e1) (simple1? e2))]
+          [else
            (nanopass-case (Lsrc Expr) e1
              [(ref ,maybe-src1 ,x1)
               (nanopass-case (Lsrc Expr) e2
@@ -2021,7 +2025,7 @@
                      (if d1 d2 (not d2))
                      (eq? d1 d2))]
                 [else #f])]
-              [else #f]))))
+             [else #f])])))
 
     (module ()
       (define-syntax define-inline