[AArch64 ACLE] Allow to define poly64_t as 'unsigned long long' on LLP64 system.

This fixes PR23414 as well.

llvm-svn: 237348
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 48c276e..a64932b 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -623,7 +623,10 @@
   case NeonTypeFlags::Poly16:
     return IsPolyUnsigned ? Context.UnsignedShortTy : Context.ShortTy;
   case NeonTypeFlags::Poly64:
-    return Context.UnsignedLongTy;
+    if (IsInt64Long)
+      return Context.UnsignedLongTy;
+    else
+      return Context.UnsignedLongLongTy;
   case NeonTypeFlags::Poly128:
     break;
   case NeonTypeFlags::Float16: