Fix host_arch detection for AIX and one new warning as error

src/hydrogen-bce.cc

 // Copyright 2013 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-bce.h"
 
 namespace v8 {
 namespace internal {
 
 
@@ skipping 362 matching lines @@
 
 BoundsCheckBbData* HBoundsCheckEliminationPhase::PreProcessBlock(
     HBasicBlock* bb) {
   BoundsCheckBbData* bb_data_list = NULL;
 
   for (HInstructionIterator it(bb); !it.Done(); it.Advance()) {
     HInstruction* i = it.Current();
     if (!i->IsBoundsCheck()) continue;
 
     HBoundsCheck* check = HBoundsCheck::cast(i);
-    int32_t offset;
+    int32_t offset = 0;
     BoundsCheckKey* key =
         BoundsCheckKey::Create(zone(), check, &offset);
     if (key == NULL) continue;
     BoundsCheckBbData** data_p = table_.LookupOrInsert(key, zone());
     BoundsCheckBbData* data = *data_p;
     if (data == NULL) {
       bb_data_list = new(zone()) BoundsCheckBbData(key,
                                                    offset,
                                                    offset,
                                                    bb,
@@ skipping 63 matching lines @@
     if (data->FatherInDominatorTree()) {
       table_.Insert(data->Key(), data->FatherInDominatorTree(), zone());
     } else {
       table_.Delete(data->Key());
     }
     data = data->NextInBasicBlock();
   }
 }
 
 } }  // namespace v8::internal