Revert "Option to truncate integers to 64 bits, part 2"

runtime/vm/regexp_assembler_ir.cc

 // Copyright (c) 2014, 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/regexp_assembler_ir.h"
 
 #include "vm/bit_vector.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 342 matching lines @@
 
   return local;
 }
 
 ConstantInstr* IRRegExpMacroAssembler::Int64Constant(int64_t value) const {
   return new (Z)
       ConstantInstr(Integer::ZoneHandle(Z, Integer::New(value, Heap::kOld)));
 }
 
 ConstantInstr* IRRegExpMacroAssembler::Uint64Constant(uint64_t value) const {
-  ASSERT(value < static_cast<uint64_t>(kMaxInt64));
-  return Int64Constant(static_cast<int64_t>(value));
+  return new (Z) ConstantInstr(
+      Integer::ZoneHandle(Z, Integer::NewFromUint64(value, Heap::kOld)));
 }
 
 ConstantInstr* IRRegExpMacroAssembler::BoolConstant(bool value) const {
   return new (Z) ConstantInstr(value ? Bool::True() : Bool::False());
 }
 
 ConstantInstr* IRRegExpMacroAssembler::StringConstant(const char* value) const {
   return new (Z)
       ConstantInstr(String::ZoneHandle(Z, String::New(value, Heap::kOld)));
 }
@@ skipping 1350 matching lines @@
   Value* index_val = BindLoadLocal(*index);
 
   return Bind(new (Z) LoadCodeUnitsInstr(pattern_val, index_val, characters,
                                          specialization_cid_,
                                          TokenPosition::kNoSource));
 }
 
 #undef __
 
 }  // namespace dart