diff --git a/js/src/tests/non262/taint/switch-case.js b/js/src/tests/non262/taint/switch-case.js
new file mode 100644
index 0000000000000..e292d4810a343
--- /dev/null
+++ b/js/src/tests/non262/taint/switch-case.js
@@ -0,0 +1,28 @@
+function taintSwitchCaseTest() {
+
+    let tableSwitchOptimized = 1;
+    let tableSwitchOptimizedTainted = Number.tainted(tableSwitchOptimized);
+
+    switch (tableSwitchOptimizedTainted) {
+        case tableSwitchOptimized:
+            break;
+        default:
+            throw new Error("Taints should not be propagated in optimized switch cases");
+    }
+
+    let tableSwitchUnoptimized = 123456789;
+    let tableSwitchUnoptimizedTainted = Number.tainted(tableSwitchUnoptimized);
+
+    switch (tableSwitchUnoptimizedTainted) {
+        case tableSwitchUnoptimized:
+            break;
+        default:
+            throw new Error("Taints should not be propagated in optimized switch cases");
+    }
+}
+
+runTaintTest(taintSwitchCaseTest);
+
+if (typeof reportCompare === 'function')
+  reportCompare(true, true);
+
diff --git a/js/src/vm/Interpreter.cpp b/js/src/vm/Interpreter.cpp
index a2d58b5590b04..d1bfdf1786dfb 100644
--- a/js/src/vm/Interpreter.cpp
+++ b/js/src/vm/Interpreter.cpp
@@ -3330,6 +3330,9 @@ bool MOZ_NEVER_INLINE JS_HAZ_JSNATIVE_CALLER js::Interpret(JSContext* cx,
       int32_t i;
       if (rref.isInt32()) {
         i = rref.toInt32();
+      }
+      else if (isTaintedNumber(rref)) {
+        i = rref.toObject().as<NumberObject>().unbox();
       } else {
         /* Use mozilla::NumberEqualsInt32 to treat -0 (double) as 0. */
         if (!rref.isDouble() || !NumberEqualsInt32(rref.toDouble(), &i)) {