[x86] Avoid memory form of PUSH/CALL for ATOM.

src/compiler/x64/instruction-selector-x64.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/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 923 matching lines @@
 
   CallBuffer buffer(zone(), descriptor, frame_state_descriptor);
 
   // Compute InstructionOperands for inputs and outputs.
   InitializeCallBuffer(node, &buffer, true, true);
 
   // Push any stack arguments.
   for (NodeVectorRIter input = buffer.pushed_nodes.rbegin();
        input != buffer.pushed_nodes.rend(); input++) {
     // TODO(titzer): handle pushing double parameters.
-    Emit(kX64Push, NULL,
-         g.CanBeImmediate(*input) ? g.UseImmediate(*input) : g.Use(*input));
+    InstructionOperand* value =
+        g.CanBeImmediate(*input)
+            ? g.UseImmediate(*input)
+            : FLAG_intel_atom ? g.UseRegister(*input) : g.Use(*input);
+    Emit(kX64Push, NULL, value);
   }
 
   // Select the appropriate opcode based on the call type.
   InstructionCode opcode;
   switch (descriptor->kind()) {
     case CallDescriptor::kCallCodeObject: {
       opcode = kArchCallCodeObject;
       break;
     }
     case CallDescriptor::kCallJSFunction:
@@ skipping 355 matching lines @@
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kWord32ShiftIsSafe;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8