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

src/compiler/ia32/instruction-selector-ia32.cc

Index: src/compiler/ia32/instruction-selector-ia32.cc
diff --git a/src/compiler/ia32/instruction-selector-ia32.cc b/src/compiler/ia32/instruction-selector-ia32.cc
index e237ebf693952bee46be9e82011daa129e7d2e50..0c939ec7567e128a65b55ec67663ae49f5c33c5e 100644
--- a/src/compiler/ia32/instruction-selector-ia32.cc
+++ b/src/compiler/ia32/instruction-selector-ia32.cc
@@ -737,8 +737,11 @@ void InstructionSelector::VisitCall(Node* node) {
   for (NodeVectorRIter input = buffer.pushed_nodes.rbegin();
        input != buffer.pushed_nodes.rend(); input++) {
     // TODO(titzer): handle pushing double parameters.
-    Emit(kIA32Push, 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(kIA32Push, NULL, value);
   }
 
   // Select the appropriate opcode based on the call type.