Preserve Smi representation of non-escaping fields.

src/hydrogen-escape-analysis.cc

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@@ skipping 178 matching lines @@
         case HValue::kAllocate: {
           if (instr != allocate) continue;
           state = NewStateForAllocation(allocate);
           break;
         }
         case HValue::kLoadNamedField: {
           HLoadNamedField* load = HLoadNamedField::cast(instr);
           int index = load->access().offset() / kPointerSize;
           if (load->object() != allocate) continue;
           ASSERT(load->access().IsInobject());
-          HValue* replacement = state->OperandAt(index);
+          HValue* load_value = state->OperandAt(index);
+          HValue* replacement = load_value;
+          Representation representation = load->representation();
+          if (representation.IsSmi()) {

[Michael Starzinger, 2014/04/25 08:35:10]

Can we factor this out into a NewLoadReplacement helper (similar to the
NewMapCheckAndInsert) to preserve readability of the giant AnalyzeDataFlow
method?

[Jarin, 2014/04/25 11:05:07]

Done.

+            Zone* zone = graph()->zone();
+            HInstruction* new_instr =
+                new(zone) HForceRepresentation(load_value, representation);
+            new_instr->InsertAfter(load);
+            replacement = new_instr;
+          }
           load->DeleteAndReplaceWith(replacement);
           if (FLAG_trace_escape_analysis) {
             PrintF("Replacing load #%d with #%d (%s)\n", instr->id(),
-                   replacement->id(), replacement->Mnemonic());
+                   load_value->id(), load_value->Mnemonic());

[Michael Starzinger, 2014/04/25 08:35:10]

nit: The logging should print the actual replacement IMHO.

[Jarin, 2014/04/25 11:05:07]

Done.

           }
           break;
         }
         case HValue::kStoreNamedField: {
           HStoreNamedField* store = HStoreNamedField::cast(instr);
           int index = store->access().offset() / kPointerSize;
           if (store->object() != allocate) continue;
           ASSERT(store->access().IsInobject());
           state = NewStateCopy(store->previous(), state);
           state->SetOperandAt(index, store->value());
@@ skipping 110 matching lines @@
   for (int i = 0; i < max_fixpoint_iteration_count; i++) {
     CollectCapturedValues();
     if (captured_.is_empty()) break;
     PerformScalarReplacement();
     captured_.Clear();
   }
 }
 
 
 } }  // namespace v8::internal