Support unaligned integer loads on ARM and MIPS.

tests/language/vm/unaligned_access_register_index_test.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// VMOptions=--optimization_counter_threshold=10 --no-background_compilation
+
+import 'dart:typed_data';
+import 'package:expect/expect.dart';
+
+unalignedUint16() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 2; i++) {
+    bytes.setUint16(i, 0xABCD);
+    Expect.equals(0xABCD, bytes.getUint16(i));
+  }
+}
+
+unalignedInt16() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 2; i++) {
+    bytes.setInt16(i, -0x1234);
+    Expect.equals(-0x1234, bytes.getInt16(i));
+  }
+}
+
+unalignedUint32() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 4; i++) {
+    bytes.setUint32(i, 0xABCDABCD);
+    Expect.equals(0xABCDABCD, bytes.getUint32(i));
+  }
+}
+
+unalignedInt32() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 4; i++) {
+    bytes.setInt32(i, -0x12341234);
+    Expect.equals(-0x12341234, bytes.getInt32(i));
+  }
+}
+
+unalignedUint64() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 8; i++) {
+    bytes.setUint64(i, 0xABCDABCD);
+    Expect.equals(0xABCDABCD, bytes.getUint64(i));
+  }
+}
+
+unalignedInt64() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 8; i++) {
+    bytes.setInt64(i, -0x12341234);
+    Expect.equals(-0x12341234, bytes.getInt64(i));
+  }
+}
+
+unalignedFloat32() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 4; i++) {
+    bytes.setFloat32(i, 16.25);
+    Expect.equals(16.25, bytes.getFloat32(i));
+  }
+}
+
+unalignedFloat64() {
+  var bytes = new ByteData(64);
+  for (var i = 0; i < 8; i++) {
+    bytes.setFloat64(i, 16.25);
+    Expect.equals(16.25, bytes.getFloat64(i));
+  }
+}
+
+main() {
+  for (var i = 0; i < 20; i++) {
+    unalignedUint16();
+    unalignedInt16();
+    unalignedUint32();
+    unalignedInt32();
+    unalignedUint64();
+    unalignedInt64();
+    unalignedFloat32();
+    unalignedFloat64();
+  }
+}