1 files changed, 44 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/cacheir/string-loadchar.js b/js/src/jit-test/tests/cacheir/string-loadchar.js
new file mode 100644
index 0000000000..f89c1d8b33
--- /dev/null
+++ b/js/src/jit-test/tests/cacheir/string-loadchar.js
@@ -0,0 +1,44 @@
+// Load Latin-1 and Two-Byte strings.
+function latin1AndTwoByte() {
+  for (var i = 0; i <= 0x03FF; ++i) {
+    var s = String.fromCodePoint(i);
+    assertEq(s[0], s);
+    assertEq(s.charAt(0), s);
+  }
+}
+
+for (var i = 0; i < 2; ++i) {
+  latin1AndTwoByte();
+}
+
+// Test bi-morphic loads.
+function stringAndArray() {
+  var xs = [["\u0100"], "\u0100"];
+  for (var i = 0; i < 200; ++i) {
+    var x = xs[i & 1];
+    var s = x[0];
+    assertEq(s.length, 1);
+    assertEq(s, "\u0100");
+  }
+}
+
+for (var i = 0; i < 2; ++i) {
+  stringAndArray();
+}
+
+function outOfBoundsFailureThenException() {
+  var name = "Object";
+
+  var j = 0;
+  while (true) {
+    // Access out-of-bounds character and then trigger an exception,
+    // when accessing a property on the undefined value.
+    name[j++].does_not_exist;
+  }
+}
+
+for (var i = 0; i < 2; ++i) {
+  try {
+    outOfBoundsFailureThenException();
+  } catch {}
+}