Revert of [crankshaft] Re-add fast-case for string add left/right.

src/hydrogen-instructions.cc

 // Copyright 2012 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/hydrogen-instructions.h"
 
 #include "src/base/bits.h"
 #include "src/double.h"
 #include "src/elements.h"
 #include "src/factory.h"
@@ skipping 3979 matching lines @@
 
 
 DEFINE_NEW_H_SIMPLE_ARITHMETIC_INSTR(HAdd, +)
 DEFINE_NEW_H_SIMPLE_ARITHMETIC_INSTR(HMul, *)
 DEFINE_NEW_H_SIMPLE_ARITHMETIC_INSTR(HSub, -)
 
 #undef DEFINE_NEW_H_SIMPLE_ARITHMETIC_INSTR
 
 
 HInstruction* HStringAdd::New(Isolate* isolate, Zone* zone, HValue* context,
-                              HValue* left, HValue* right,
+                              HValue* left, HValue* right, Strength strength,
                               PretenureFlag pretenure_flag,
                               StringAddFlags flags,
                               Handle<AllocationSite> allocation_site) {
   if (FLAG_fold_constants && left->IsConstant() && right->IsConstant()) {
     HConstant* c_right = HConstant::cast(right);
     HConstant* c_left = HConstant::cast(left);
     if (c_left->HasStringValue() && c_right->HasStringValue()) {
       Handle<String> left_string = c_left->StringValue();
       Handle<String> right_string = c_right->StringValue();
       // Prevent possible exception by invalid string length.
       if (left_string->length() + right_string->length() < String::kMaxLength) {
         MaybeHandle<String> concat = isolate->factory()->NewConsString(
             c_left->StringValue(), c_right->StringValue());
         return HConstant::New(isolate, zone, context, concat.ToHandleChecked());
       }
     }
   }
-  return new (zone)
-      HStringAdd(context, left, right, pretenure_flag, flags, allocation_site);
+  return new (zone) HStringAdd(context, left, right, strength, pretenure_flag,
+                               flags, allocation_site);
 }
 
 
 std::ostream& HStringAdd::PrintDataTo(std::ostream& os) const {  // NOLINT
   if ((flags() & STRING_ADD_CHECK_BOTH) == STRING_ADD_CHECK_BOTH) {
     os << "_CheckBoth";
   } else if ((flags() & STRING_ADD_CHECK_BOTH) == STRING_ADD_CHECK_LEFT) {
     os << "_CheckLeft";
   } else if ((flags() & STRING_ADD_CHECK_BOTH) == STRING_ADD_CHECK_RIGHT) {
     os << "_CheckRight";
@@ skipping 677 matching lines @@
     case HObjectAccess::kExternalMemory:
       os << "[external-memory]";
       break;
   }
 
   return os << "@" << access.offset();
 }
 
 }  // namespace internal
 }  // namespace v8