Add unboxed Mint for X64

runtime/vm/deopt_instructions.h

 // 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.
 
 #ifndef VM_DEOPT_INSTRUCTIONS_H_
 #define VM_DEOPT_INSTRUCTIONS_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
@@ skipping 199 matching lines @@
 class DeoptInstr : public ZoneAllocated {
  public:
   enum Kind {
     kRetAddress,
     kConstant,
     kWord,
     kDouble,
     kFloat32x4,
     kFloat64x2,
     kInt32x4,
-    // Mints are split into low and high words. Each word can be in a register
-    // or stack slot. Note Mints are only used on 32-bit architectures.
+    // Mints are split into low and high words on 32-bit architectures. Each
+    // word can be in a register or stack slot. Note Mint pairs are only
+    // used on 32-bit architectures.
     kMintPair,
+    // Mints are held in one word on 64-bit architectures.
+    kMint,
     kInt32,
     kUint32,
     kPcMarker,
     kPp,
     kCallerFp,
     kCallerPp,
     kCallerPc,
     kSuffix,
     kMaterializedObjectRef,
     kMaterializeObject
@@ skipping 266 matching lines @@
                        DeoptInfo* info,
                        Smi* reason);
 
  private:
   static const intptr_t kEntrySize = 3;
 };
 
 }  // namespace dart
 
 #endif  // VM_DEOPT_INSTRUCTIONS_H_