Expand PPC64 atomic load and store

Use of store or load with the atomic specifier on 64-bit types would
cause instruction-selection failures. As with the 32-bit case, these
can use the default expansion in terms of cmp-and-swap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171072 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 9cc4e96..b14c181 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -443,6 +443,8 @@
 
   setOperationAction(ISD::ATOMIC_LOAD,  MVT::i32, Expand);
   setOperationAction(ISD::ATOMIC_STORE, MVT::i32, Expand);
+  setOperationAction(ISD::ATOMIC_LOAD,  MVT::i64, Expand);
+  setOperationAction(ISD::ATOMIC_STORE, MVT::i64, Expand);
 
   setBooleanContents(ZeroOrOneBooleanContent);
   setBooleanVectorContents(ZeroOrOneBooleanContent); // FIXME: Is this correct?