Improve range analysis for smi phi

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 1743 matching lines @@
   if (has_int32_value_) {
     Range* result = new(zone) Range(int32_value_, int32_value_);
     result->set_can_be_minus_zero(false);
     return result;
   }
   return HValue::InferRange(zone);
 }
 
 
 Range* HPhi::InferRange(Zone* zone) {
-  if (representation().IsInteger32()) {
+  Representation r = representation();
+  if (r.IsSmiOrInteger32()) {
     if (block()->IsLoopHeader()) {
-      Range* range = new(zone) Range(kMinInt, kMaxInt);
+      Range* range = r.IsSmi()
+          ? new(zone) Range(Smi::kMinValue, Smi::kMaxValue)
+          : new(zone) Range(kMinInt, kMaxInt);
       return range;
     } else {
       Range* range = OperandAt(0)->range()->Copy(zone);
       for (int i = 1; i < OperandCount(); ++i) {
         range->Union(OperandAt(i)->range());
       }
       return range;
     }
   } else {
     return HValue::InferRange(zone);
@@ skipping 2101 matching lines @@
     case kBackingStore:
       if (!name_.is_null()) stream->Add(*String::cast(*name_)->ToCString());
       stream->Add("[backing-store]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal