Trivial change to set UseLeaForSP flag in addition to toggling
the FeatureLeaForSP feature bit when llvm auto detects Intel Atom.

Patch by Andy Zhang

llvm-svn: 155655
diff --git a/llvm/lib/Target/X86/X86Subtarget.cpp b/llvm/lib/Target/X86/X86Subtarget.cpp
index fbc5b8c..b924dc4 100644
--- a/llvm/lib/Target/X86/X86Subtarget.cpp
+++ b/llvm/lib/Target/X86/X86Subtarget.cpp
@@ -255,6 +255,8 @@
     // Set processor type. Currently only Atom is detected.
     if (Family == 6 && Model == 28) {
       X86ProcFamily = IntelAtom;
+
+      UseLeaForSP = true;
       ToggleFeature(X86::FeatureLeaForSP);
     }