diff --git a/collects/tests/typed-racket/succeed/pr13339.rkt b/collects/tests/typed-racket/succeed/pr13339.rkt
new file mode 100644
index 00000000..28da2e3a
--- /dev/null
+++ b/collects/tests/typed-racket/succeed/pr13339.rkt
@@ -0,0 +1,28 @@
+#lang typed/racket
+
+(require racket/flonum
+         typed/rackunit)
+
+(: neg (Real -> Real))
+(define (neg x) (- x))
+
+(: flneg (Flonum -> Flonum))
+(define (flneg x) (fl* -1.0 x))
+
+(check-eqv? (neg +inf.0) -inf.0)
+(check-eqv? (neg -inf.0) +inf.0)
+(check-eqv? (neg +nan.0) +nan.0)
+(check-eqv? (neg -0.0) +0.0)
+(check-eqv? (neg +0.0) -0.0)
+
+(check-eqv? (flneg +inf.0) (neg +inf.0))
+(check-eqv? (flneg -inf.0) (neg -inf.0))
+(check-eqv? (flneg +nan.0) (neg +nan.0))
+(check-eqv? (flneg -0.0)   (neg -0.0))
+(check-eqv? (flneg +0.0)   (neg +0.0))
+
+(check-eqv? (- +inf.0) (neg +inf.0))
+(check-eqv? (- -inf.0) (neg -inf.0))
+(check-eqv? (- +nan.0) (neg +nan.0))
+(check-eqv? (- -0.0)   (neg -0.0))
+(check-eqv? (- +0.0)   (neg +0.0))
diff --git a/collects/typed-racket/optimizer/float.rkt b/collects/typed-racket/optimizer/float.rkt
index 78efa0b2..4db200ee 100644
--- a/collects/typed-racket/optimizer/float.rkt
+++ b/collects/typed-racket/optimizer/float.rkt
@@ -180,7 +180,7 @@
            #:with opt
            (begin (log-optimization "unary float" float-opt-msg this-syntax)
                   (add-disappeared-use #'op)
-                  #'(unsafe-fl- 0.0 f.opt)))
+                  #'(unsafe-fl* -1.0 f.opt)))
   (pattern (#%plain-app (~and op (~literal /)) f:float-expr)
            #:with opt
            (begin (log-optimization "unary float" float-opt-msg this-syntax)