[compiler] [wasm] Introduce Word32/64ReverseBytes as TF Optional Opcode

src/compiler/int64-lowering.cc

Index: src/compiler/int64-lowering.cc
diff --git a/src/compiler/int64-lowering.cc b/src/compiler/int64-lowering.cc
index 320d481c5dde36188fc72685e64450756a8db3ba..f89c56d544b32292e196a188bfc4d19fdf0850e4 100644
--- a/src/compiler/int64-lowering.cc
+++ b/src/compiler/int64-lowering.cc
@@ -778,6 +778,15 @@ void Int64Lowering::LowerNode(Node* node) {
       }
       break;
     }
+    case IrOpcode::kWord64ReverseBytes: {
+      DCHECK(machine()->Word32ReverseBytes().IsSupported());

[titzer, 2016/07/29 18:21:53]

Can you remove this DCHECK? E.g. the optional operator's .op() method will fail
if it is not supported below.

+      Node* input = node->InputAt(0);
+      ReplaceNode(node, graph()->NewNode(machine()->Word32ReverseBytes().op(),
+                                         GetReplacementHigh(input)),
+                  graph()->NewNode(machine()->Word32ReverseBytes().op(),
+                                   GetReplacementLow(input)));
+      break;
+    }
 
     default: { DefaultLowering(node); }
   }