Disable lowering to StringAdd due to various issues.

test/cctest/compiler/test-js-typed-lowering.cc

 // Copyright 2014 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/v8.h"
 #include "test/cctest/cctest.h"
 
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/node-properties-inl.h"
@@ skipping 168 matching lines @@
 static Type* I32Type(bool is_signed) {
   return is_signed ? Type::Signed32() : Type::Unsigned32();
 }
 
 
 static IrOpcode::Value NumberToI32(bool is_signed) {
   return is_signed ? IrOpcode::kNumberToInt32 : IrOpcode::kNumberToUint32;
 }
 
 
+// TODO(turbofan): Lowering of StringAdd is disabled for now.
+#if 0
 TEST(StringBinops) {
   JSTypedLoweringTester R;
 
   for (size_t i = 0; i < arraysize(kStringTypes); ++i) {
     Node* p0 = R.Parameter(kStringTypes[i], 0);
 
     for (size_t j = 0; j < arraysize(kStringTypes); ++j) {
       Node* p1 = R.Parameter(kStringTypes[j], 1);
 
       Node* add = R.Binop(R.javascript.Add(), p0, p1);
       Node* r = R.reduce(add);
 
       R.CheckPureBinop(IrOpcode::kStringAdd, r);
       CHECK_EQ(p0, r->InputAt(0));
       CHECK_EQ(p1, r->InputAt(1));
     }
   }
 }
+#endif
 
 
 TEST(AddNumber1) {
   JSTypedLoweringTester R;
   for (size_t i = 0; i < arraysize(kNumberTypes); ++i) {
     Node* p0 = R.Parameter(kNumberTypes[i], 0);
     Node* p1 = R.Parameter(kNumberTypes[i], 1);
     Node* add = R.Binop(R.javascript.Add(), p0, p1);
     Node* r = R.reduce(add);
 
@@ skipping 1147 matching lines @@
           CHECK_EQ(p1, r->InputAt(0));
           CHECK_EQ(p0, r->InputAt(1));
         } else {
           CHECK_EQ(p0, r->InputAt(0));
           CHECK_EQ(p1, r->InputAt(1));
         }
       }
     }
   }
 }