Replace tagged keys for fast access by smi, and use smi in boundscheck.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index d68a52bb97b93709d9163c95d97a046a2ba55975..ece3a5919b4e5babba7d3ff919261f4bf952c106 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1947,12 +1947,6 @@ LInstruction* LChunkBuilder::DoCheckSmi(HCheckSmi* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoCheckSmiOrInt32(HCheckSmiOrInt32* instr) {
-  LOperand* value = UseRegisterAtStart(instr->value());
-  return AssignEnvironment(new(zone()) LCheckSmi(value));
-}
-
-
 LInstruction* LChunkBuilder::DoCheckFunction(HCheckFunction* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
   return AssignEnvironment(new(zone()) LCheckFunction(value));
@@ -1999,7 +1993,7 @@ LInstruction* LChunkBuilder::DoConstant(HConstant* instr) {
   } else if (r.IsDouble()) {
     LOperand* temp = TempRegister();
     return DefineAsRegister(new(zone()) LConstantD(temp));
-  } else if (r.IsTagged()) {
+  } else if (r.IsSmiOrTagged()) {
     return DefineAsRegister(new(zone()) LConstantT);
   } else {
     UNREACHABLE();
@@ -2114,9 +2108,9 @@ LInstruction* LChunkBuilder::DoLoadExternalArrayPointer(
 
 LInstruction* LChunkBuilder::DoLoadKeyed(HLoadKeyed* instr) {
   ASSERT(instr->key()->representation().IsInteger32() ||
-         instr->key()->representation().IsTagged());
+         instr->key()->representation().IsSmi());
   ElementsKind elements_kind = instr->elements_kind();
-  bool clobbers_key = instr->key()->representation().IsTagged();
+  bool clobbers_key = instr->key()->representation().IsSmi();
   LOperand* key = clobbers_key
       ? UseTempRegister(instr->key())
       : UseRegisterOrConstantAtStart(instr->key());
@@ -2157,7 +2151,7 @@ LInstruction* LChunkBuilder::DoLoadKeyedGeneric(HLoadKeyedGeneric* instr) {
 
 LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
   ElementsKind elements_kind = instr->elements_kind();
-  bool clobbers_key = instr->key()->representation().IsTagged();
+  bool clobbers_key = instr->key()->representation().IsSmi();
 
   if (!instr->is_external()) {
     ASSERT(instr->elements()->representation().IsTagged());