1 files changed, 30 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/cacheir/map-has-value.js b/js/src/jit-test/tests/cacheir/map-has-value.js
new file mode 100644
index 0000000000..fddb1e8b5d
--- /dev/null
+++ b/js/src/jit-test/tests/cacheir/map-has-value.js
@@ -0,0 +1,30 @@
+// Return a new map, possibly filling some dummy entries to enforce creating
+// multiple hash buckets.
+function createMap(values, n) {
+  var xs = [...values];
+  for (var i = 0; i < n; ++i) {
+    xs.push({});
+  }
+  return new Map(xs.map((x, i) => [x, i]));
+}
+
+function runTest(fn) {
+  fn(0);
+  fn(100);
+}
+
+function testPolymorphic(n) {
+  var xs = [10, 10.5, "test", Symbol("?"), 123n, -123n, {}, []];
+  var ys = [-0, NaN, "bad", Symbol("!"), 42n, -99n, {}, []];
+  var zs = [...xs, ...ys];
+  var map = createMap(xs, n);
+
+  var N = 128;
+  var c = 0;
+  for (var i = 0; i < N; ++i) {
+    var z = zs[i & 15];
+    if (map.has(z)) c++;
+  }
+  assertEq(c, N / 2);
+}
+runTest(testPolymorphic);