[wasm] Add I64Eqz operator.

src/compiler/wasm-compiler.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/compiler/wasm-compiler.h"
 
 #include "src/isolate-inl.h"
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/platform.h"
@@ skipping 847 matching lines @@
     // kExprI64UConvertI32:
     case wasm::kExprI64UConvertI32:
       op = m->ChangeUint32ToUint64();
       break;
     // kExprF64ReinterpretI64:
     // kExprI64ReinterpretF64:
     // kExprI64Clz:
     // kExprI64Ctz:
     // kExprI64Popcnt:
     // kExprF32SConvertI64:
+    case wasm::kExprI64Eqz:
+      op = m->Word64Equal();
+      return graph()->NewNode(op, input, jsgraph()->Int64Constant(0));
     case wasm::kExprF32SConvertI64:
       if (m->Is32()) {
         return BuildF32SConvertI64(input);
       }
       op = m->RoundInt64ToFloat32();
       break;
     // kExprF32UConvertI64:
     case wasm::kExprF32UConvertI64:
       if (m->Is32()) {
         return BuildF32UConvertI64(input);
@@ skipping 1694 matching lines @@
         static_cast<int>(function.code_end_offset - function.code_start_offset),
         decode_ms, static_cast<int>(graph.NodeCount()), compile_ms);
   }
   return code;
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8