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

src/base/cpu.h

Index: src/base/cpu.h
diff --git a/src/base/cpu.h b/src/base/cpu.h
index 8c41f9d77a776739d5643bf317e6c3c6233a5a0e..6a3afaf842ea954f1bc6d1becff4fdec84d6b6e2 100644
--- a/src/base/cpu.h
+++ b/src/base/cpu.h
@@ -40,6 +40,7 @@ class CPU FINAL {
   int family() const { return family_; }
   int ext_family() const { return ext_family_; }
   int type() const { return type_; }
+  bool is_atom() const { return is_atom_; }
 
   // arm implementer/part information
   int implementer() const { return implementer_; }
@@ -106,6 +107,7 @@ class CPU FINAL {
   bool has_ssse3_;
   bool has_sse41_;
   bool has_sse42_;
+  bool is_atom_;
   bool has_avx_;
   bool has_fma3_;
   bool has_idiva_;