diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index 9dc239bc65..96b7f0dc8d 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -2029,12 +2029,6 @@ 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));
@@ -2079,7 +2073,7 @@ LInstruction* LChunkBuilder::DoConstant(HConstant* instr) {
     return DefineAsRegister(new(zone()) LConstantI);
   } else if (r.IsDouble()) {
     return DefineAsRegister(new(zone()) LConstantD);
-  } else if (r.IsTagged() || r.IsSmi()) {
+  } else if (r.IsSmiOrTagged()) {
     return DefineAsRegister(new(zone()) LConstantT);
   } else {
     UNREACHABLE();
@@ -2191,7 +2185,7 @@ 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();
   LOperand* key = UseRegisterOrConstantAtStart(instr->key());
   LLoadKeyed* result = NULL;
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 04661d326b..b175c58d07 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -3276,7 +3276,7 @@ void LCodeGen::DoLoadKeyedExternalArray(LLoadKeyed* instr) {
     key = ToRegister(instr->key());
   }
   int element_size_shift = ElementsKindToShiftSize(elements_kind);
-  int shift_size = (instr->hydrogen()->key()->representation().IsTagged())
+  int shift_size = (instr->hydrogen()->key()->representation().IsSmi())
       ? (element_size_shift - kSmiTagSize) : element_size_shift;
   int additional_offset = instr->additional_index() << element_size_shift;
 
@@ -3348,7 +3348,7 @@ void LCodeGen::DoLoadKeyedFixedDoubleArray(LLoadKeyed* instr) {
   Register scratch = scratch0();
 
   int element_size_shift = ElementsKindToShiftSize(FAST_DOUBLE_ELEMENTS);
-  int shift_size = (instr->hydrogen()->key()->representation().IsTagged())
+  int shift_size = (instr->hydrogen()->key()->representation().IsSmi())
       ? (element_size_shift - kSmiTagSize) : element_size_shift;
   int constant_key = 0;
   if (key_is_constant) {
@@ -3393,7 +3393,7 @@ void LCodeGen::DoLoadKeyedFixedArray(LLoadKeyed* instr) {
     // representation for the key to be an integer, the input gets replaced
     // during bound check elimination with the index argument to the bounds
     // check, which can be tagged, so that case must be handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ add(scratch, elements, Operand::PointerOffsetFromSmiKey(key));
     } else {
       __ add(scratch, elements, Operand(key, LSL, kPointerSizeLog2));
@@ -4329,7 +4329,7 @@ void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
   if (instr->index()->IsConstantOperand()) {
     int constant_index =
         ToInteger32(LConstantOperand::cast(instr->index()));
-    if (instr->hydrogen()->length()->representation().IsTagged()) {
+    if (instr->hydrogen()->length()->representation().IsSmi()) {
       __ mov(ip, Operand(Smi::FromInt(constant_index)));
     } else {
       __ mov(ip, Operand(constant_index));
@@ -4357,7 +4357,7 @@ void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
     key = ToRegister(instr->key());
   }
   int element_size_shift = ElementsKindToShiftSize(elements_kind);
-  int shift_size = (instr->hydrogen()->key()->representation().IsTagged())
+  int shift_size = (instr->hydrogen()->key()->representation().IsSmi())
       ? (element_size_shift - kSmiTagSize) : element_size_shift;
   int additional_offset = instr->additional_index() << element_size_shift;
 
@@ -4430,7 +4430,7 @@ void LCodeGen::DoStoreKeyedFixedDoubleArray(LStoreKeyed* instr) {
     key = ToRegister(instr->key());
   }
   int element_size_shift = ElementsKindToShiftSize(FAST_DOUBLE_ELEMENTS);
-  int shift_size = (instr->hydrogen()->key()->representation().IsTagged())
+  int shift_size = (instr->hydrogen()->key()->representation().IsSmi())
       ? (element_size_shift - kSmiTagSize) : element_size_shift;
   Operand operand = key_is_constant
       ? Operand((constant_key << element_size_shift) +
@@ -4476,7 +4476,7 @@ void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
     // representation for the key to be an integer, the input gets replaced
     // during bound check elimination with the index argument to the bounds
     // check, which can be tagged, so that case must be handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ add(scratch, elements, Operand::PointerOffsetFromSmiKey(key));
     } else {
       __ add(scratch, elements, Operand(key, LSL, kPointerSizeLog2));
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 52cbfaea20..d5f32b88a1 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -410,7 +410,7 @@ HValue* CodeStubGraphBuilder<KeyedLoadFastElementStub>::BuildCodeStub() {
   HInstruction* load = BuildUncheckedMonomorphicElementAccess(
       GetParameter(0), GetParameter(1), NULL, NULL,
       casted_stub()->is_js_array(), casted_stub()->elements_kind(),
-      false, NEVER_RETURN_HOLE, STANDARD_STORE, Representation::Tagged());
+      false, NEVER_RETURN_HOLE, STANDARD_STORE, Representation::Smi());
   return load;
 }
 
@@ -456,7 +456,7 @@ HValue* CodeStubGraphBuilder<KeyedStoreFastElementStub>::BuildCodeStub() {
       GetParameter(0), GetParameter(1), GetParameter(2), NULL,
       casted_stub()->is_js_array(), casted_stub()->elements_kind(),
       true, NEVER_RETURN_HOLE, casted_stub()->store_mode(),
-      Representation::Tagged());
+      Representation::Smi());
 
   return GetParameter(2);
 }
@@ -572,11 +572,9 @@ HValue* CodeStubGraphBuilder<ArraySingleArgumentConstructorStub>::
       new(zone()) HConstant(initial_capacity, Representation::Tagged());
   AddInstruction(initial_capacity_node);
 
-  // Since we're forcing Integer32 representation for this HBoundsCheck,
-  // there's no need to Smi-check the index.
   HBoundsCheck* checked_arg = AddBoundsCheck(argument, max_alloc_length,
                                              ALLOW_SMI_KEY,
-                                             Representation::Tagged());
+                                             Representation::Smi());
   IfBuilder if_builder(this);
   if_builder.IfCompare(checked_arg, constant_zero, Token::EQ);
   if_builder.Then();
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 0c03b5908e..fa8ee8646f 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1143,16 +1143,15 @@ void HBoundsCheck::InferRepresentation(HInferRepresentation* h_infer) {
   HValue* actual_length = length()->ActualValue();
   HValue* actual_index = index()->ActualValue();
   if (key_mode_ == DONT_ALLOW_SMI_KEY ||
-      !actual_length->representation().IsTagged()) {
+      !actual_length->representation().IsSmiOrTagged()) {
     r = Representation::Integer32();
-  } else if (actual_index->representation().IsTagged() ||
-      (actual_index->IsConstant() &&
-       HConstant::cast(actual_index)->HasSmiValue())) {
-    // If the index is tagged, or a constant that holds a Smi, allow the length
-    // to be tagged, since it is usually already tagged from loading it out of
-    // the length field of a JSArray. This allows for direct comparison without
-    // untagging.
-    r = Representation::Tagged();
+  } else if (actual_index->representation().IsSmiOrTagged() ||
+             (actual_index->IsConstant() &&
+              HConstant::cast(actual_index)->HasSmiValue())) {
+    // If the index is smi, or a constant that holds a Smi, allow the length to
+    // be smi, since it is usually already smi from loading it out of the length
+    // field of a JSArray. This allows for direct comparison without untagging.
+    r = Representation::Smi();
   } else {
     r = Representation::Integer32();
   }
@@ -2945,15 +2944,6 @@ HType HCheckSmi::CalculateInferredType() {
 }
 
 
-void HCheckSmiOrInt32::InferRepresentation(HInferRepresentation* h_infer) {
-  ASSERT(CheckFlag(kFlexibleRepresentation));
-  ASSERT(UseCount() == 1);
-  HUseIterator use = uses();
-  Representation r = use.value()->RequiredInputRepresentation(use.index());
-  UpdateRepresentation(r, h_infer, "checksmiorint32");
-}
-
-
 HType HPhi::CalculateInferredType() {
   HType result = HType::Uninitialized();
   for (int i = 0; i < OperandCount(); ++i) {
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 775a0e25df..116c4e7aa7 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -93,7 +93,6 @@ class LChunkBuilder;
   V(CheckNonSmi)                               \
   V(CheckPrototypeMaps)                        \
   V(CheckSmi)                                  \
-  V(CheckSmiOrInt32)                           \
   V(ClampToUint8)                              \
   V(ClassOfTestAndBranch)                      \
   V(CompareIDAndBranch)                        \
@@ -1721,7 +1720,7 @@ class HChange: public HUnaryOperation {
     SetFlag(kUseGVN);
     if (deoptimize_on_undefined) SetFlag(kDeoptimizeOnUndefined);
     if (is_truncating) SetFlag(kTruncatingToInt32);
-    if (value->type().IsSmi()) {
+    if (value->representation().IsSmi() || value->type().IsSmi()) {
       set_type(HType::Smi());
     } else {
       set_type(HType::TaggedNumber());
@@ -2952,38 +2951,6 @@ class HCheckSmi: public HUnaryOperation {
 };
 
 
-class HCheckSmiOrInt32: public HUnaryOperation {
- public:
-  explicit HCheckSmiOrInt32(HValue* value) : HUnaryOperation(value) {
-    SetFlag(kFlexibleRepresentation);
-    SetFlag(kUseGVN);
-  }
-
-  virtual int RedefinedOperandIndex() { return 0; }
-  virtual Representation RequiredInputRepresentation(int index) {
-    return representation();
-  }
-  virtual void InferRepresentation(HInferRepresentation* h_infer);
-
-  virtual Representation observed_input_representation(int index) {
-    return Representation::Integer32();
-  }
-
-  virtual HValue* Canonicalize() {
-    if (representation().IsTagged() && !value()->type().IsSmi()) {
-      return this;
-    } else {
-      return value();
-    }
-  }
-
-  DECLARE_CONCRETE_INSTRUCTION(CheckSmiOrInt32)
-
- protected:
-  virtual bool DataEquals(HValue* other) { return true; }
-};
-
-
 class HPhi: public HValue {
  public:
   HPhi(int merged_index, Zone* zone)
@@ -3578,8 +3545,7 @@ class HBoundsCheckBaseIndexInformation;
 class HBoundsCheck: public HTemplateInstruction<2> {
  public:
   // Normally HBoundsCheck should be created using the
-  // HGraphBuilder::AddBoundsCheck() helper, which also guards the index with
-  // a HCheckSmiOrInt32 check.
+  // HGraphBuilder::AddBoundsCheck() helper.
   // However when building stubs, where we know that the arguments are Int32,
   // it makes sense to invoke this constructor directly.
   HBoundsCheck(HValue* index,
@@ -5459,7 +5425,7 @@ class ArrayInstructionInterface {
 
   static Representation KeyedAccessIndexRequirement(Representation r) {
     return r.IsInteger32() ? Representation::Integer32()
-                           : Representation::Tagged();
+                           : Representation::Smi();
   }
 };
 
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 8954e61df0..54ae31f0f2 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -1003,14 +1003,6 @@ HBoundsCheck* HGraphBuilder::AddBoundsCheck(HValue* index,
                                             HValue* length,
                                             BoundsCheckKeyMode key_mode,
                                             Representation r) {
-  if (!index->type().IsSmi()) {
-    index = new(graph()->zone()) HCheckSmiOrInt32(index);
-    AddInstruction(HCheckSmiOrInt32::cast(index));
-  }
-  if (!length->type().IsSmi()) {
-    length = new(graph()->zone()) HCheckSmiOrInt32(length);
-    AddInstruction(HCheckSmiOrInt32::cast(length));
-  }
   HBoundsCheck* result = new(graph()->zone()) HBoundsCheck(
       index, length, key_mode, r);
   AddInstruction(result);
@@ -1333,11 +1325,7 @@ HInstruction* HGraphBuilder::BuildUncheckedMonomorphicElementAccess(
 
     elements = BuildCheckForCapacityGrow(object, elements, elements_kind,
                                          length, key, is_js_array);
-    if (!key->type().IsSmi()) {
-      checked_key = AddInstruction(new(zone) HCheckSmiOrInt32(key));
-    } else {
-      checked_key = key;
-    }
+    checked_key = key;
   } else {
     checked_key = AddBoundsCheck(
         key, length, ALLOW_SMI_KEY, checked_index_representation);
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 26e7103466..3e237638d7 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -3364,7 +3364,7 @@ Operand LCodeGen::BuildFastArrayOperand(
                        + offset);
   } else {
     // Take the tag bit into account while computing the shift size.
-    if (key_representation.IsTagged() && (shift_size >= 1)) {
+    if (key_representation.IsSmi() && (shift_size >= 1)) {
       shift_size -= kSmiTagSize;
     }
     ScaleFactor scale_factor = static_cast<ScaleFactor>(shift_size);
@@ -4359,7 +4359,7 @@ void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
   if (instr->index()->IsConstantOperand()) {
     int constant_index =
         ToInteger32(LConstantOperand::cast(instr->index()));
-    if (instr->hydrogen()->length()->representation().IsTagged()) {
+    if (instr->hydrogen()->length()->representation().IsSmi()) {
       __ cmp(ToOperand(instr->length()),
              Immediate(Smi::FromInt(constant_index)));
     } else {
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 8981c4d328..ffec17b6ee 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -2068,12 +2068,6 @@ LInstruction* LChunkBuilder::DoCheckSmi(HCheckSmi* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoCheckSmiOrInt32(HCheckSmiOrInt32* instr) {
-  LOperand* value = UseAtStart(instr->value());
-  return AssignEnvironment(new(zone()) LCheckSmi(value));
-}
-
-
 LInstruction* LChunkBuilder::DoCheckFunction(HCheckFunction* instr) {
   // If the target is in new space, we'll emit a global cell compare and so
   // want the value in a register.  If the target gets promoted before we
@@ -2144,7 +2138,7 @@ LInstruction* LChunkBuilder::DoConstant(HConstant* instr) {
     } else {
       return DefineX87TOS(new(zone()) LConstantD(NULL));
     }
-  } else if (r.IsTagged()) {
+  } else if (r.IsSmiOrTagged()) {
     return DefineAsRegister(new(zone()) LConstantT);
   } else {
     UNREACHABLE();
@@ -2261,7 +2255,7 @@ 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 = ExternalArrayOpRequiresTemp(
       instr->key()->representation(), elements_kind);
@@ -2330,7 +2324,7 @@ LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
   if (!instr->is_external()) {
     ASSERT(instr->elements()->representation().IsTagged());
     ASSERT(instr->key()->representation().IsInteger32() ||
-           instr->key()->representation().IsTagged());
+           instr->key()->representation().IsSmi());
 
     if (instr->value()->representation().IsDouble()) {
       LOperand* object = UseRegisterAtStart(instr->elements());
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 47d8601cdb..6712e760e5 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -1596,7 +1596,7 @@ inline static bool ExternalArrayOpRequiresTemp(
   // Operations that require the key to be divided by two to be converted into
   // an index cannot fold the scale operation into a load and need an extra
   // temp register to do the work.
-  return key_representation.IsTagged() &&
+  return key_representation.IsSmi() &&
       (elements_kind == EXTERNAL_BYTE_ELEMENTS ||
        elements_kind == EXTERNAL_UNSIGNED_BYTE_ELEMENTS ||
        elements_kind == EXTERNAL_PIXEL_ELEMENTS);
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 109c25ad5e..44d056fe13 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -2922,7 +2922,7 @@ void LCodeGen::DoLoadKeyedExternalArray(LLoadKeyed* instr) {
     // gets replaced during bound check elimination with the index argument
     // to the bounds check, which can be tagged, so that case must be
     // handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else if (instr->hydrogen()->IsDehoisted()) {
       // Sign extend key because it could be a 32 bit negative value
@@ -2995,7 +2995,7 @@ void LCodeGen::DoLoadKeyedFixedDoubleArray(LLoadKeyed* instr) {
     // representation for the key to be an integer, the input gets replaced
     // during bound check elimination with the index argument to the bounds
     // check, which can be tagged, so that case must be handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else if (instr->hydrogen()->IsDehoisted()) {
       // Sign extend key because it could be a 32 bit negative value
@@ -3037,7 +3037,7 @@ void LCodeGen::DoLoadKeyedFixedArray(LLoadKeyed* instr) {
     // gets replaced during bound check elimination with the index
     // argument to the bounds check, which can be tagged, so that
     // case must be handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else if (instr->hydrogen()->IsDehoisted()) {
       // Sign extend key because it could be a 32 bit negative value
@@ -4042,20 +4042,20 @@ void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
 
   if (instr->length()->IsRegister()) {
     Register reg = ToRegister(instr->length());
-    if (!instr->hydrogen()->length()->representation().IsTagged()) {
+    if (!instr->hydrogen()->length()->representation().IsSmi()) {
       __ AssertZeroExtended(reg);
     }
     if (instr->index()->IsConstantOperand()) {
       int constant_index =
           ToInteger32(LConstantOperand::cast(instr->index()));
-      if (instr->hydrogen()->length()->representation().IsTagged()) {
+      if (instr->hydrogen()->length()->representation().IsSmi()) {
         __ Cmp(reg, Smi::FromInt(constant_index));
       } else {
         __ cmpq(reg, Immediate(constant_index));
       }
     } else {
       Register reg2 = ToRegister(instr->index());
-      if (!instr->hydrogen()->index()->representation().IsTagged()) {
+      if (!instr->hydrogen()->index()->representation().IsSmi()) {
         __ AssertZeroExtended(reg2);
       }
       __ cmpq(reg, reg2);
@@ -4065,7 +4065,7 @@ void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
     if (instr->index()->IsConstantOperand()) {
       int constant_index =
           ToInteger32(LConstantOperand::cast(instr->index()));
-      if (instr->hydrogen()->length()->representation().IsTagged()) {
+      if (instr->hydrogen()->length()->representation().IsSmi()) {
         __ Cmp(length, Smi::FromInt(constant_index));
       } else {
         __ cmpq(length, Immediate(constant_index));
@@ -4088,7 +4088,7 @@ void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
     // gets replaced during bound check elimination with the index
     // argument to the bounds check, which can be tagged, so that case
     // must be handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else if (instr->hydrogen()->IsDehoisted()) {
       // Sign extend key because it could be a 32 bit negative value
@@ -4152,7 +4152,7 @@ void LCodeGen::DoStoreKeyedFixedDoubleArray(LStoreKeyed* instr) {
     // input gets replaced during bound check elimination with the index
     // argument to the bounds check, which can be tagged, so that case
     // must be handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else if (instr->hydrogen()->IsDehoisted()) {
       // Sign extend key because it could be a 32 bit negative value
@@ -4195,7 +4195,7 @@ void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
     // input gets replaced during bound check elimination with the index
     // argument to the bounds check, which can be tagged, so that case
     // must be handled here, too.
-    if (instr->hydrogen()->key()->representation().IsTagged()) {
+    if (instr->hydrogen()->key()->representation().IsSmi()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else if (instr->hydrogen()->IsDehoisted()) {
       // Sign extend key because it could be a 32 bit negative value
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index b74b1a8a9a..de21c10946 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1946,12 +1946,6 @@ 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));
@@ -1998,7 +1992,7 @@ 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();
@@ -2113,9 +2107,9 @@ 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());
@@ -2156,7 +2150,7 @@ 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());