Box values of LoadCodeUnits that fall outside of smi range on 32bit platforms.

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
diff --git a/runtime/vm/intermediate_language_mips.cc b/runtime/vm/intermediate_language_mips.cc
index 3f40519d64c623413627c839d0532c30838ede3a..1257aed0d757a0f6f3f6ee2cbe1edabf10ec3c26 100644
--- a/runtime/vm/intermediate_language_mips.cc
+++ b/runtime/vm/intermediate_language_mips.cc
@@ -1241,18 +1241,6 @@ void LoadIndexedInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 }
 
 
-Representation LoadCodeUnitsInstr::representation() const {
-  switch (class_id()) {
-    case kOneByteStringCid:
-    case kTwoByteStringCid:
-      return kTagged;
-    default:
-      UNIMPLEMENTED();
-      return kTagged;
-  }
-}
-
-
 LocationSummary* LoadCodeUnitsInstr::MakeLocationSummary(Isolate* isolate,
                                                          bool opt) const {
   const intptr_t kNumInputs = 2;