Fix hole handling, and ensure smi representation is handled properly

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 db98f238912ebf072790556b80b02f84334fc9ac..cd567fbdf14d87ec3196c86a5c04e148b184bdc4 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -718,9 +718,9 @@ LInstruction* LChunkBuilder::DoDeoptimize(HDeoptimize* instr) {
 
 LInstruction* LChunkBuilder::DoShift(Token::Value op,
                                      HBitwiseBinaryOperation* instr) {
-  if (instr->representation().IsTagged()) {
-    ASSERT(instr->left()->representation().IsTagged());
-    ASSERT(instr->right()->representation().IsTagged());
+  if (instr->representation().IsSmiOrTagged()) {
+    ASSERT(instr->left()->representation().IsSmiOrTagged());
+    ASSERT(instr->right()->representation().IsSmiOrTagged());
 
     LOperand* left = UseFixed(instr->left(), rdx);
     LOperand* right = UseFixed(instr->right(), rax);
@@ -788,8 +788,8 @@ LInstruction* LChunkBuilder::DoArithmeticT(Token::Value op,
          op == Token::SUB);
   HValue* left = instr->left();
   HValue* right = instr->right();
-  ASSERT(left->representation().IsTagged());
-  ASSERT(right->representation().IsTagged());
+  ASSERT(left->representation().IsSmiOrTagged());
+  ASSERT(right->representation().IsSmiOrTagged());
   LOperand* left_operand = UseFixed(left, rdx);
   LOperand* right_operand = UseFixed(right, rax);
   LArithmeticT* result =
@@ -1308,9 +1308,9 @@ LInstruction* LChunkBuilder::DoBitwise(HBitwise* instr) {
     LOperand* right = UseOrConstantAtStart(instr->BetterRightOperand());
     return DefineSameAsFirst(new(zone()) LBitI(left, right));
   } else {
-    ASSERT(instr->representation().IsTagged());
-    ASSERT(instr->left()->representation().IsTagged());
-    ASSERT(instr->right()->representation().IsTagged());
+    ASSERT(instr->representation().IsSmiOrTagged());
+    ASSERT(instr->left()->representation().IsSmiOrTagged());
+    ASSERT(instr->right()->representation().IsSmiOrTagged());
 
     LOperand* left = UseFixed(instr->left(), rdx);
     LOperand* right = UseFixed(instr->right(), rax);
@@ -1349,7 +1349,7 @@ LInstruction* LChunkBuilder::DoDiv(HDiv* instr) {
     LDivI* result = new(zone()) LDivI(dividend, divisor, temp);
     return AssignEnvironment(DefineFixed(result, rax));
   } else {
-    ASSERT(instr->representation().IsTagged());
+    ASSERT(instr->representation().IsSmiOrTagged());
     return DoArithmeticT(Token::DIV, instr);
   }
 }
@@ -1450,7 +1450,7 @@ LInstruction* LChunkBuilder::DoMod(HMod* instr) {
             instr->CheckFlag(HValue::kCanOverflow))
         ? AssignEnvironment(result)
         : result;
-  } else if (instr->representation().IsTagged()) {
+  } else if (instr->representation().IsSmiOrTagged()) {
     return DoArithmeticT(Token::MOD, instr);
   } else {
     ASSERT(instr->representation().IsDouble());
@@ -1480,7 +1480,7 @@ LInstruction* LChunkBuilder::DoMul(HMul* instr) {
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::MUL, instr);
   } else {
-    ASSERT(instr->representation().IsTagged());
+    ASSERT(instr->representation().IsSmiOrTagged());
     return DoArithmeticT(Token::MUL, instr);
   }
 }
@@ -1501,7 +1501,7 @@ LInstruction* LChunkBuilder::DoSub(HSub* instr) {
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::SUB, instr);
   } else {
-    ASSERT(instr->representation().IsTagged());
+    ASSERT(instr->representation().IsSmiOrTagged());
     return DoArithmeticT(Token::SUB, instr);
   }
 }
@@ -1533,7 +1533,7 @@ LInstruction* LChunkBuilder::DoAdd(HAdd* instr) {
   } else if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::ADD, instr);
   } else {
-    ASSERT(instr->representation().IsTagged());
+    ASSERT(instr->representation().IsSmiOrTagged());
     return DoArithmeticT(Token::ADD, instr);
   }
   return NULL;
@@ -1814,12 +1814,6 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
   if (from.IsSmi()) {
     if (to.IsTagged()) {
       LOperand* value = UseRegister(instr->value());
-      // For now, always deopt on hole.
-      if (instr->value()->IsLoadKeyed() &&
-          HLoadKeyed::cast(instr->value())->UsesMustHandleHole()) {
-        return AssignEnvironment(
-            DefineSameAsFirst(new(zone()) LCheckSmiAndReturn(value)));
-      }
       return DefineSameAsFirst(new(zone()) LDummyUse(value));
     }
     from = Representation::Tagged();
@@ -1845,16 +1839,7 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
       ASSERT(to.IsInteger32());
       LOperand* value = UseRegister(instr->value());
       if (instr->value()->type().IsSmi()) {
-        LInstruction* result =
-            DefineSameAsFirst(new(zone()) LSmiUntag(value, false));
-        if (instr->value()->IsLoadKeyed()) {
-          HLoadKeyed* load_keyed = HLoadKeyed::cast(instr->value());
-          if (load_keyed->UsesMustHandleHole() &&
-              load_keyed->hole_mode() == NEVER_RETURN_HOLE) {
-            return AssignEnvironment(result);
-          }
-        }
-        return result;
+        return DefineSameAsFirst(new(zone()) LSmiUntag(value, false));
       } else {
         bool truncating = instr->CanTruncateToInt32();
         LOperand* xmm_temp = truncating ? NULL : FixedTemp(xmm1);
@@ -1971,7 +1956,7 @@ LInstruction* LChunkBuilder::DoClampToUint8(HClampToUint8* instr) {
   } else if (input_rep.IsInteger32()) {
     return DefineSameAsFirst(new(zone()) LClampIToUint8(reg));
   } else {
-    ASSERT(input_rep.IsTagged());
+    ASSERT(input_rep.IsSmiOrTagged());
     // Register allocator doesn't (yet) support allocation of double
     // temps. Reserve xmm1 explicitly.
     LClampTToUint8* result = new(zone()) LClampTToUint8(reg,