Avoid using a register for constant external array indices.

src/lithium.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 148 matching lines @@
 void LPointerMap::PrintTo(StringStream* stream) {
   stream->Add("{");
   for (int i = 0; i < pointer_operands_.length(); ++i) {
     if (i != 0) stream->Add(";");
     pointer_operands_[i]->PrintTo(stream);
   }
   stream->Add("} @%d", position());
 }
 
 
+int ExternalArrayTypeToShiftSize(ExternalArrayType type) {
+  switch (type) {
+    case kExternalByteArray:
+    case kExternalUnsignedByteArray:
+    case kExternalPixelArray:
+      return 0;
+    case kExternalShortArray:
+    case kExternalUnsignedShortArray:
+      return 1;
+    case kExternalIntArray:
+    case kExternalUnsignedIntArray:
+    case kExternalFloatArray:
+      return 2;
+    case kExternalDoubleArray:
+      return 3;
+  }
+  UNREACHABLE();
+  return 0;
+}
+
+
 } }  // namespace v8::internal