[vm] Implement gradual refinement of types

runtime/vm/aot_optimizer.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/aot_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/branch_optimizer.h"
 #include "vm/cha.h"
 #include "vm/compiler.h"
@@ skipping 1711 matching lines @@
       CallTargets* targets = CallTargets::Create(Z, unary_checks);
       ASSERT(targets->HasSingleTarget());
       const Function& target = targets->FirstTarget();
       StaticCallInstr* call = StaticCallInstr::FromCall(Z, instr, target);
       instr->ReplaceWith(call, current_iterator());
       return;
     }
   }
   switch (instr->token_kind()) {
     case Token::kEQ:
+    case Token::kNE:
     case Token::kLT:
     case Token::kLTE:
     case Token::kGT:
     case Token::kGTE: {
       if (HasOnlyTwoOf(*instr->ic_data(), kSmiCid) ||
           HasLikelySmiOperand(instr)) {
         ASSERT(receiver_idx == 0);
         Definition* left = instr->ArgumentAt(0);
         Definition* right = instr->ArgumentAt(1);
         CheckedSmiComparisonInstr* smi_op = new (Z)
@@ skipping 356 matching lines @@
                                   FlowGraph::kEffect);
         current_iterator()->RemoveCurrentFromGraph();
       }
     }
   }
 }
 
 #endif  // DART_PRECOMPILER
 
 }  // namespace dart