[turbofan] Add and use bytecode loop assigment analysis

src/interpreter/bytecode-array-accessor.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/bytecode-array-accessor.h"
 
 #include "src/interpreter/bytecode-decoder.h"
 #include "src/interpreter/interpreter-intrinsics.h"
 #include "src/objects-inl.h"
 
@@ skipping 171 matching lines @@
     return current_offset() + relative_offset + current_prefix_offset();
   } else if (interpreter::Bytecodes::IsJumpConstant(bytecode)) {
     Smi* smi = Smi::cast(*GetConstantForIndexOperand(0));
     return current_offset() + smi->value() + current_prefix_offset();
   } else {
     UNREACHABLE();
     return kMinInt;
   }
 }
 
+bool BytecodeArrayAccessor::OffsetWithinBytecode(int offset) const {
+  return current_offset() <= offset &&
+         offset < current_offset() + current_bytecode_size();
+}
+
 std::ostream& BytecodeArrayAccessor::PrintTo(std::ostream& os) const {
   return BytecodeDecoder::Decode(
       os, bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_,
       bytecode_array()->parameter_count());
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8