Inline String.fromCharCode in hydrogen.

test/mjsunit/string-fromcharcode.js

Index: test/mjsunit/string-fromcharcode.js
diff --git a/test/mjsunit/string-fromcharcode.js b/test/mjsunit/string-fromcharcode.js
index 1986dda0fb8e3539759564dedb892018bb4a611f..c23bd8ceb1c1edd6064f2eeb990d6b93782799b0 100644
--- a/test/mjsunit/string-fromcharcode.js
+++ b/test/mjsunit/string-fromcharcode.js
@@ -25,8 +25,28 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+// Flags: --allow-natives-syntax
+
 // Test String.fromCharCode.
 
+// Test char codes larger than 0xffff.
+var expected = "";
+for (var i = 100; i < 500; i++) {
+  expected += String.fromCharCode(i);
+}
+
+function testCharCodeTruncation() {
+  var result = "";
+  for (var i = 0x100000 + 100; i < 0x100000 + 500; i++) {
+    result += String.fromCharCode(i);
+  }
+  return result;
+}
+
+assertEquals(expected, testCharCodeTruncation());
+assertEquals(expected, testCharCodeTruncation());
+%OptimizeFunctionOnNextCall(testCharCodeTruncation);
+assertEquals(expected, testCharCodeTruncation());
 
 // Test various receivers and arguments passed to String.fromCharCode.