Fixed handling of polymorphic array accesses with constant index

src/hydrogen-instructions.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1414 matching lines @@
   }
   return this;
 }
 
 
 void HTypeof::PrintDataTo(StringStream* stream) {
   value()->PrintNameTo(stream);
 }
 
 
+static bool CanRepresentationContainDouble(Representation rep, double value) {

[Jakob Kummerow, 2014/03/12 09:16:24]

nit: How about moving this to Representation::CanRepresent(double value) {...} ?

+  if (rep.IsDouble() || rep.is_more_general_than(Representation::Double())) {
+    return true;
+  }
+  if (IsInt32Double(value)) {
+    if (rep.IsInteger32()) return true;
+    if (rep.IsSmi()) return Smi::IsValid(static_cast<int32_t>(value));
+  }
+  return false;
+}
+
+
 HInstruction* HForceRepresentation::New(Zone* zone, HValue* context,
-       HValue* value, Representation required_representation) {
+       HValue* value, Representation representation) {
   if (FLAG_fold_constants && value->IsConstant()) {
     HConstant* c = HConstant::cast(value);
     if (c->HasNumberValue()) {
       double double_res = c->DoubleValue();
-      if (IsInt32Double(double_res)) {
+      if (CanRepresentationContainDouble(representation, double_res)) {
         return HConstant::New(zone, context,
                               static_cast<int32_t>(double_res),
-                              required_representation);
+                              representation);
       }
     }
   }
-  return new(zone) HForceRepresentation(value, required_representation);
+  return new(zone) HForceRepresentation(value, representation);
 }
 
 
 void HForceRepresentation::PrintDataTo(StringStream* stream) {
   stream->Add("%s ", representation().Mnemonic());
   value()->PrintNameTo(stream);
 }
 
 
 void HChange::PrintDataTo(StringStream* stream) {
@@ skipping 3094 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal