[wasm] I added I64Eq to the Int64Lowering.

src/compiler/int64-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/compiler/int64-lowering.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-properties.h"
@@ skipping 275 matching lines @@
           graph()->NewNode(machine()->Word32Xor(), GetReplacementHigh(left),
                            GetReplacementHigh(right));
       ReplaceNode(node, low_node, high_node);
       break;
     }
 
     // kExprI64Shl:
     // kExprI64ShrU:
     // kExprI64ShrS:
     // kExprI64Eq:
+    case IrOpcode::kWord64Equal: {
+      DCHECK(node->InputCount() == 2);
+      Node* left = node->InputAt(0);
+      Node* right = node->InputAt(1);
+
+      Node* replacement = graph()->NewNode(

[titzer, 2016/02/23 15:49:30]

Can you add a 

TODO(wasm): Use explicit comparisons and && here?

Since we might want to explore that as a better codegen option. The TODO(wasm)
indicates that it's a performance enhancement and not a functionality problem.

+          machine()->Word32Equal(),
+          graph()->NewNode(
+              machine()->Word32Or(),
+              graph()->NewNode(machine()->Word32Xor(), GetReplacementLow(left),
+                               GetReplacementLow(right)),
+              graph()->NewNode(machine()->Word32Xor(), GetReplacementHigh(left),
+                               GetReplacementHigh(right))),
+          graph()->NewNode(common()->Int32Constant(0)));
+
+      ReplaceNode(node, replacement, nullptr);
+      break;
+    }
     // kExprI64Ne:
     // kExprI64LtS:
     // kExprI64LeS:
     // kExprI64LtU:
     // kExprI64LeU:
     // kExprI64GtS:
     // kExprI64GeS:
     // kExprI64GtU:
     // kExprI64GeU:
 
@@ skipping 57 matching lines @@
 }
 
 Node* Int64Lowering::GetReplacementHigh(Node* node) {
   Node* result = replacements_[node->id()].high;
   DCHECK(result);
   return result;
 }
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8