Adding Smi support to Add, Sub, Mul, and Bitwise

src/hydrogen-representation-changes.cc

Index: src/hydrogen-representation-changes.cc
diff --git a/src/hydrogen-representation-changes.cc b/src/hydrogen-representation-changes.cc
index 45d35b2006b9956d7a953d840649f8070e98651b..63b7b4d6ec8e326a2900e1be3c8b4557fabe70f5 100644
--- a/src/hydrogen-representation-changes.cc
+++ b/src/hydrogen-representation-changes.cc
@@ -45,13 +45,14 @@ void HRepresentationChangesPhase::InsertRepresentationChangeForUse(
   // information we treat constants like normal instructions and insert the
   // change instructions for them.
   HInstruction* new_value = NULL;
-  bool is_truncating = use_value->CheckFlag(HValue::kTruncatingToInt32);
+  bool is_truncating_to_smi = use_value->CheckFlag(HValue::kTruncatingToSmi);
+  bool is_truncating_to_int = use_value->CheckFlag(HValue::kTruncatingToInt32);
   bool allow_undefined_as_nan =
       use_value->CheckFlag(HValue::kAllowUndefinedAsNaN);
   if (value->IsConstant()) {
     HConstant* constant = HConstant::cast(value);
     // Try to create a new copy of the constant with the new representation.
-    if (is_truncating && to.IsInteger32()) {
+    if (is_truncating_to_int && to.IsInteger32()) {
       Maybe<HConstant*> res = constant->CopyToTruncatedInt32(graph()->zone());
       if (res.has_value) new_value = res.value;
     } else {
@@ -61,7 +62,8 @@ void HRepresentationChangesPhase::InsertRepresentationChangeForUse(
 
   if (new_value == NULL) {
     new_value = new(graph()->zone()) HChange(value, to,
-                                             is_truncating,
+                                             is_truncating_to_smi,
+                                             is_truncating_to_int,
                                              allow_undefined_as_nan);
   }
 
@@ -108,6 +110,8 @@ void HRepresentationChangesPhase::Run() {
     HPhi* phi = phi_list->at(i);
     if (phi->representation().IsInteger32()) {
       phi->SetFlag(HValue::kTruncatingToInt32);
+    } else if (phi->representation().IsSmi()) {
+      phi->SetFlag(HValue::kTruncatingToSmi);
     }
   }
 
@@ -119,13 +123,18 @@ void HRepresentationChangesPhase::Run() {
       HValue* use = it.value();
       Representation input_representation =
           use->RequiredInputRepresentation(it.index());
-      if (!input_representation.IsInteger32() ||
-          !use->CheckFlag(HValue::kTruncatingToInt32)) {
+      if ((phi->representation().IsInteger32() &&
+           !(input_representation.IsInteger32() &&
+             use->CheckFlag(HValue::kTruncatingToInt32))) ||
+          (phi->representation().IsSmi() &&
+           !(input_representation.IsSmi() ||
+             use->CheckFlag(HValue::kTruncatingToSmi)))) {
         if (FLAG_trace_representation) {
           PrintF("#%d Phi is not truncating because of #%d %s\n",
                  phi->id(), it.value()->id(), it.value()->Mnemonic());
         }
         phi->ClearFlag(HValue::kTruncatingToInt32);
+        phi->ClearFlag(HValue::kTruncatingToSmi);
         worklist.Add(phi, zone());
         break;
       }
@@ -137,13 +146,16 @@ void HRepresentationChangesPhase::Run() {
     for (int i = 0; i < current->OperandCount(); ++i) {
       HValue* input = current->OperandAt(i);
       if (input->IsPhi() &&
-          input->representation().IsInteger32() &&
-          input->CheckFlag(HValue::kTruncatingToInt32)) {
+          ((input->representation().IsInteger32() &&
+            input->CheckFlag(HValue::kTruncatingToInt32)) ||
+           (input->representation().IsSmi() &&
+            input->CheckFlag(HValue::kTruncatingToSmi)))) {
         if (FLAG_trace_representation) {
           PrintF("#%d Phi is not truncating because of #%d %s\n",
                  input->id(), current->id(), current->Mnemonic());
         }
         input->ClearFlag(HValue::kTruncatingToInt32);
+        input->ClearFlag(HValue::kTruncatingToSmi);
         worklist.Add(HPhi::cast(input), zone());
       }
     }