set the ppc64 stack pointer right, dynamic alloca now works for ppc64


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31028 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 09569a8..4285b68 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -261,7 +261,11 @@
   setSetCCResultType(MVT::i32);
   setShiftAmountType(MVT::i32);
   setSetCCResultContents(ZeroOrOneSetCCResult);
-  setStackPointerRegisterToSaveRestore(PPC::R1);
+  
+  if (TM.getSubtarget<PPCSubtarget>().isPPC64())
+    setStackPointerRegisterToSaveRestore(PPC::X1);
+  else 
+    setStackPointerRegisterToSaveRestore(PPC::R1);
   
   // We have target-specific dag combine patterns for the following nodes:
   setTargetDAGCombine(ISD::SINT_TO_FP);