Implement code to keep the stack pointer aligned to an 8 byte boundary.
This improves the performance of the power benchmark by a few percent.
This will be neccesary for SSE code, which requires 16 byte alignment of
the stack.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5320 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index ee8318f..8351f09 100644
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -386,7 +386,7 @@
   // [ESP + 8] -- second argument, if first argument is four bytes in size
   //    ... 
   //
-  unsigned ArgOffset = 4;
+  unsigned ArgOffset = 0;   // Frame mechanisms handle retaddr slot
   MachineFrameInfo *MFI = F->getFrameInfo();
 
   for (Function::aiterator I = Fn.abegin(), E = Fn.aend(); I != E; ++I) {