[Atomics] Make Atomics.exchange a builtin using TF

src/compiler/machine-graph-verifier.cc

Index: src/compiler/machine-graph-verifier.cc
diff --git a/src/compiler/machine-graph-verifier.cc b/src/compiler/machine-graph-verifier.cc
index ecabbe057530b6eaec020dbe1ff4dd479ee9fcf1..bc20537136a9cfaf9e5eeac61ec4014c00abae6d 100644
--- a/src/compiler/machine-graph-verifier.cc
+++ b/src/compiler/machine-graph-verifier.cc
@@ -148,6 +148,10 @@ class MachineRepresentationInferrer {
             representation_vector_[node->id()] =
                 PromoteRepresentation(AtomicStoreRepresentationOf(node->op()));
             break;
+          case IrOpcode::kAtomicExchange:
+            representation_vector_[node->id()] = PromoteRepresentation(
+                AtomicExchangeRepresentationOf(node->op()).representation());
+            break;
           case IrOpcode::kStore:
           case IrOpcode::kProtectedStore:
             representation_vector_[node->id()] = PromoteRepresentation(
@@ -449,6 +453,7 @@ class MachineRepresentationChecker {
             }
             break;
           case IrOpcode::kAtomicStore:
+          case IrOpcode::kAtomicExchange:

[binji, 2017/01/13 00:08:50]

Looks like kStore above is identical, can it be rolled in also?

[aseemgarg, 2017/01/14 01:48:19]

Done.

             CheckValueInputIsTaggedOrPointer(node, 0);
             CheckValueInputRepresentationIs(
                 node, 1, MachineType::PointerRepresentation());