Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/CodeGen/MachineMemOperand.h b/linux-x64/clang/include/llvm/CodeGen/MachineMemOperand.h
index dea0d80..078ef7c 100644
--- a/linux-x64/clang/include/llvm/CodeGen/MachineMemOperand.h
+++ b/linux-x64/clang/include/llvm/CodeGen/MachineMemOperand.h
@@ -184,7 +184,7 @@
   /// atomic operations the atomic ordering requirements when store does not
   /// occur must also be specified.
   MachineMemOperand(MachinePointerInfo PtrInfo, Flags flags, uint64_t s,
-                    unsigned base_alignment,
+                    uint64_t a,
                     const AAMDNodes &AAInfo = AAMDNodes(),
                     const MDNode *Ranges = nullptr,
                     SyncScope::ID SSID = SyncScope::System,