diff --git a/js/src/jit/BaselineIC.cpp b/js/src/jit/BaselineIC.cpp
index d5326b848dd3..3ea1541556a2 100644
--- a/js/src/jit/BaselineIC.cpp
+++ b/js/src/jit/BaselineIC.cpp
@@ -4765,6 +4765,10 @@ CanOptimizeDenseOrUnboxedArraySetElem(JSObject* obj, uint32_t index,
     if (initLength < oldInitLength || capacity < oldCapacity)
         return false;
 
+    // Unboxed arrays need to be able to emit floating point code.
+    if (obj->is<UnboxedArrayObject>() && !obj->runtimeFromMainThread()->jitSupportsFloatingPoint)
+        return false;
+
     Shape* shape = obj->maybeShape();
 
     // Cannot optimize if the shape changed.