X87: [Atomics] Remove Atomics code stubs; use TF ops.

src/compiler/x87/instruction-selector-x87.cc

Index: src/compiler/x87/instruction-selector-x87.cc
diff --git a/src/compiler/x87/instruction-selector-x87.cc b/src/compiler/x87/instruction-selector-x87.cc
index a1537ebdd82556d3a810f531f53e8d21f2634092..ae1019f4e6c0c7b143758622835c35896e76b42d 100644
--- a/src/compiler/x87/instruction-selector-x87.cc
+++ b/src/compiler/x87/instruction-selector-x87.cc
@@ -1590,6 +1590,14 @@ void InstructionSelector::VisitFloat64InsertHighWord32(Node* node) {
        g.UseRegister(left), g.UseRegister(right));
 }
 
+void InstructionSelector::VisitAtomicLoad(Node* node) {
+  LoadRepresentation load_rep = LoadRepresentationOf(node->op());
+  DCHECK(load_rep.representation() == MachineRepresentation::kWord8 ||
+         load_rep.representation() == MachineRepresentation::kWord16 ||
+         load_rep.representation() == MachineRepresentation::kWord32);
+  USE(load_rep);
+  VisitLoad(node);
+}
 
 // static
 MachineOperatorBuilder::Flags