Optimize one byte string comparisons.

runtime/vm/il_printer.cc

Index: runtime/vm/il_printer.cc
===================================================================
--- runtime/vm/il_printer.cc	(revision 31282)
+++ runtime/vm/il_printer.cc	(working copy)
@@ -977,6 +977,28 @@
 }
 
 
+void StringCharCodeInstr::PrintTo(BufferFormatter* f) const {
+  PrintUse(f, *this);
+  if (is_used()) {
+    if (HasSSATemp() || (temp_index() != -1)) f->Print(" <- ");
+  }
+  f->Print("%s:%" Pd "(",
+      (kind() == kToCharCode) ? "StringToCharCode" : "StringFromCharCode",
+      GetDeoptId());
+  PrintOperandsTo(f);
+  f->Print(")");
+  if (range_ != NULL) {
+    f->Print(" ");
+    range_->PrintTo(f);
+  }
+
+  if (type_ != NULL) {
+    f->Print(" ");
+    type_->PrintTo(f);
+  }
+}
+
+
 void Environment::PrintTo(BufferFormatter* f) const {
   f->Print(" env={ ");
   int arg_count = 0;