[turbofan] support for Int64 in CheckedLoad/CheckedStore on 64-bit platforms.

src/compiler/mips/code-generator-mips.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/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
 #include "src/mips/macro-assembler-mips.h"
@@ skipping 840 matching lines @@
       break;
     case kCheckedStoreWord32:
       ASSEMBLE_CHECKED_STORE_INTEGER(sw);
       break;
     case kCheckedStoreFloat32:
       ASSEMBLE_CHECKED_STORE_FLOAT(Single, swc1);
       break;
     case kCheckedStoreFloat64:
       ASSEMBLE_CHECKED_STORE_FLOAT(Double, sdc1);
       break;
+    case kCheckedLoadWord64:
+    case kCheckedStoreWord64:
+      UNREACHABLE();  // currently unsupported checked int64 load/store.
+      break;
   }
 }
 
 
 #define UNSUPPORTED_COND(opcode, condition)                                  \
   OFStream out(stdout);                                                      \
   out << "Unsupported " << #opcode << " condition: \"" << condition << "\""; \
   UNIMPLEMENTED();
 
 static bool convertCondition(FlagsCondition condition, Condition& cc) {
@@ skipping 509 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8