Fix unsound fxquotient optimization.

Closes PR13827.
(cherry picked from commit 5e30416)

collects/tests/typed-racket/optimizer/tests/fixnum-bounded-expr.rkt

@@ -25,7 +25,7 @@ TR opt: fixnum-bounded-expr.rkt 99:5 (+ 300 301) -- fixnum bounded expr
 TR opt: fixnum-bounded-expr.rkt 99:17 (+ 301 302) -- fixnum bounded expr
 TR opt: fixnum-bounded-expr.rkt 99:0 (fx- (+ 300 301) (+ 301 302)) -- fixnum fx-
 TR opt: fixnum-bounded-expr.rkt 102:0 (fx* 4 5) -- fixnum fx*
-TR opt: fixnum-bounded-expr.rkt 105:0 (fxquotient (ann 34 Nonnegative-Fixnum) (ann -4 Fixnum)) -- fixnum fxquotient
+TR opt: fixnum-bounded-expr.rkt 105:0 (fxquotient (ann 34 Nonnegative-Fixnum) (ann -4 Negative-Fixnum)) -- fixnum fxquotient
 TR opt: fixnum-bounded-expr.rkt 108:0 (fxabs (ann 64235 Nonnegative-Fixnum)) -- fixnum fxabs
 28
 89525
@@ -102,7 +102,7 @@ TR opt: fixnum-bounded-expr.rkt 108:0 (fxabs (ann 64235 Nonnegative-Fixnum)) --
 (fx* 4 5) ; ok, (* Byte Byte)
 (fx* 300 300) ; not ok
 
-(fxquotient (ann 34 Nonnegative-Fixnum) (ann -4 Fixnum))
+(fxquotient (ann 34 Nonnegative-Fixnum) (ann -4 Negative-Fixnum))
 (fxquotient -4 -5) ; not ok
 
 (fxabs (ann 64235 Nonnegative-Fixnum)) ; ok

collects/tests/typed-racket/optimizer/tests/invalid-fxquotient.rkt

@@ -1,11 +1,14 @@
 #;
 (
-TR missed opt: invalid-fxquotient.rkt 10:21 (quotient fixnum-min -1) -- out of fixnum range
+TR missed opt: invalid-fxquotient.rkt 12:21 (quotient fixnum-min -1) -- out of fixnum range
 #t
 )
 
 #lang typed/racket/base
 
+(require racket/fixnum)
+
 (define: fixnum-min : Nonpositive-Fixnum (assert (- (expt 2 30)) fixnum?))
 (define: q : Natural (quotient fixnum-min -1)) ; this can't be optimized safely
 (= 1073741824 q)
+(define (bad) (fxquotient 3 0)) ; can't be optimized

collects/typed-racket/optimizer/fixnum.rkt

@@ -194,9 +194,8 @@
            (begin (log-optimization "fixnum fx*" fixnum-opt-msg this-syntax)
                   (add-disappeared-use #'op)
                   #'(unsafe-fx* n1.opt n2.opt)))
-  (pattern (#%plain-app (~and op (~literal fxquotient)) n1:fixnum-expr n2:fixnum-expr)
-           #:when (and (subtypeof? #'n1 -NonNegFixnum)
-                       (subtypeof? #'n2 -Fixnum))
+  (pattern (#%plain-app (~and op (~literal fxquotient)) n1:fixnum-expr n2:nonzero-fixnum-expr)
+           #:when (subtypeof? #'n1 -NonNegFixnum)
            #:with opt
            (begin (log-optimization "fixnum fxquotient" fixnum-opt-msg this-syntax)
                   (add-disappeared-use #'op)