Track representations of fields

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 bb2545048338e7b41ef717d9901bf0ab7db64221..2095a5db43b56600cbbc4e917306fcf775957de7 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -2031,9 +2031,10 @@ LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
 
 
 LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
-  ASSERT(instr->representation().IsTagged());
   LOperand* obj = UseRegisterAtStart(instr->object());
-  return DefineAsRegister(new(zone()) LLoadNamedField(obj));
+  LOperand* temp = instr->representation().IsDouble() ? TempRegister() : NULL;
+  ASSERT(temp == NULL || FLAG_track_double_fields);
+  return DefineAsRegister(new(zone()) LLoadNamedField(obj, temp));
 }
 
 
@@ -2270,8 +2271,12 @@ LInstruction* LChunkBuilder::DoStoreNamedField(HStoreNamedField* instr) {
   LOperand* val;
   if (needs_write_barrier) {
     val = UseTempRegister(instr->value());
-  } else if (StoreConstantValueAllowed(instr->value())) {
+  } else if (StoreConstantValueAllowed(instr->value()) &&
+             !(FLAG_track_double_fields &&
+               instr->field_representation().IsDouble())) {
     val = UseRegisterOrConstant(instr->value());
+  } else if (FLAG_track_fields && instr->field_representation().IsSmi()) {
+    val = UseTempRegister(instr->value());
   } else {
     val = UseRegister(instr->value());
   }
@@ -2281,7 +2286,12 @@ LInstruction* LChunkBuilder::DoStoreNamedField(HStoreNamedField* instr) {
   LOperand* temp = (!instr->is_in_object() || needs_write_barrier ||
       needs_write_barrier_for_map) ? TempRegister() : NULL;
 
-  return new(zone()) LStoreNamedField(obj, val, temp);
+  LStoreNamedField* result = new(zone()) LStoreNamedField(obj, val, temp);
+  if ((FLAG_track_fields && instr->field_representation().IsSmi()) ||
+      (FLAG_track_double_fields && instr->field_representation().IsDouble())) {
+    return AssignEnvironment(result);
+  }
+  return result;
 }