Allow uint32 value on optimized frames if they are consumed by safe operations.

src/hydrogen-instructions.h

 // 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 544 matching lines @@
     // sets this flag, it must implement SetSideEffectDominator() and should
     // indicate which side effects to track by setting GVN flags.
     kTrackSideEffectDominators,
     kCanOverflow,
     kBailoutOnMinusZero,
     kCanBeDivByZero,
     kDeoptimizeOnUndefined,
     kIsArguments,
     kTruncatingToInt32,
     kIsDead,
-    kLastFlag = kIsDead
+    // Instructions that are allowed to produce full range unsigned integer
+    // values are marked with kUint32 flag. If arithmetic shift or a load from
+    // EXTERNAL_UNSIGNED_INT_ELEMENTS array is not marked with this flag
+    // it will deoptimize if result does not fit into signed integer range.
+    // HGraph::ComputeSafeUint32Operations is responsible for setting this
+    // flag.
+    kUint32,
+    kLastFlag = kUint32
   };
 
   STATIC_ASSERT(kLastFlag < kBitsPerInt);
 
   static const int kChangesToDependsFlagsLeftShift = 1;
 
   static GVNFlag ChangesFlagFromInt(int x) {
     return static_cast<GVNFlag>(x * 2);
   }
   static GVNFlag DependsOnFlagFromInt(int x) {
@@ skipping 1973 matching lines @@
   int32_t NumberValueAsInteger32() const {
     ASSERT(HasNumberValue());
     // Irrespective of whether a numeric HConstant can be safely
     // represented as an int32, we store the (in some cases lossy)
     // representation of the number in int32_value_.
     return int32_value_;
   }
 
   bool ToBoolean();
 
+  bool IsUint32() {
+    return HasInteger32Value() && (Integer32Value() >= 0);
+  }
+
   virtual intptr_t Hashcode() {
     ASSERT_ALLOCATION_DISABLED;
     intptr_t hash;
 
     if (has_int32_value_) {
       hash = static_cast<intptr_t>(int32_value_);
     } else if (has_double_value_) {
       hash = static_cast<intptr_t>(BitCast<int64_t>(double_value_));
     } else {
       ASSERT(!handle_.is_null());
@@ skipping 2679 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(LoadFieldByIndex);
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_