Track representations of fields

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index b240de7f11dc8d88bf09467090e2cf8a95130056..d2fed7dc265b16ec76c3ed2de8bf63cf09f6f658 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -2114,8 +2114,10 @@ LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
 
 
 LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
-  return DefineAsRegister(
-      new(zone()) LLoadNamedField(UseRegisterAtStart(instr->object())));
+  LOperand* obj = UseRegisterAtStart(instr->object());
+  LOperand* temp = instr->representation().IsDouble() ? TempRegister() : NULL;
+  ASSERT(temp == NULL || FLAG_track_double_fields);
+  return DefineAsRegister(new(zone()) LLoadNamedField(obj, temp));
 }
 
 
@@ -2319,14 +2321,20 @@ LInstruction* LChunkBuilder::DoStoreNamedField(HStoreNamedField* instr) {
         : UseRegisterAtStart(instr->object());
   }
 
-  LOperand* val = needs_write_barrier
-      ? UseTempRegister(instr->value())
-      : UseRegister(instr->value());
+  LOperand* val =
+      needs_write_barrier ||
+      (FLAG_track_fields && instr->field_representation().IsSmi())
+          ? UseTempRegister(instr->value()) : UseRegister(instr->value());
 
   // We need a temporary register for write barrier of the map field.
   LOperand* temp = 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;
 }