diff --git a/js/src/jit-test/tests/parallel/bug975636.js b/js/src/jit-test/tests/parallel/bug975636.js
new file mode 100644
index 000000000000..adccea12d19a
--- /dev/null
+++ b/js/src/jit-test/tests/parallel/bug975636.js
@@ -0,0 +1,7 @@
+load(libdir + "parallelarray-helpers.js");
+if (getBuildConfiguration().parallelJS) {
+  function f(x) { return [] << 0; }
+  var a = Array.buildPar(9, f);
+  var b = Array.build(9, f);
+  assertEqArray(a, b);
+}
diff --git a/js/src/jit/ParallelFunctions.cpp b/js/src/jit/ParallelFunctions.cpp
index abb960615c12..c7f3dae42511 100644
--- a/js/src/jit/ParallelFunctions.cpp
+++ b/js/src/jit/ParallelFunctions.cpp
@@ -497,9 +497,9 @@ jit::BitNotPar(ForkJoinContext *cx, HandleValue in, int32_t *out)
     JS_BEGIN_MACRO                                                      \
     int32_t left, right;                                                \
     if (lhs.isObject() || rhs.isObject())                               \
-        return TP_RETRY_SEQUENTIALLY;                                   \
-    if (!NonObjectToInt32(cx, lhs, &left) ||                         \
-        !NonObjectToInt32(cx, rhs, &right))                          \
+        return false;                                                   \
+    if (!NonObjectToInt32(cx, lhs, &left) ||                            \
+        !NonObjectToInt32(cx, rhs, &right))                             \
     {                                                                   \
         return false;                                                   \
     }                                                                   \
@@ -528,7 +528,7 @@ jit::BitAndPar(ForkJoinContext *cx, HandleValue lhs, HandleValue rhs, int32_t *o
 bool
 jit::BitLshPar(ForkJoinContext *cx, HandleValue lhs, HandleValue rhs, int32_t *out)
 {
-    BIT_OP(left << (right & 31));
+    BIT_OP(uint32_t(left) << (right & 31));
 }
 
 bool