[DebugInfo] Avoid name conflict of generated VLA expression variable.

Summary:
This patch also adds the 'DW_AT_artificial' flag to the generated variable.

Addresses the issues mentioned in http://llvm.org/PR30553.

Reviewers: CarlosAlbertoEnciso, probinson, aprantl

Reviewed By: aprantl

Subscribers: JDevlieghere, cfe-commits

Differential Revision: https://reviews.llvm.org/D43189

llvm-svn: 324988
diff --git a/clang/test/OpenMP/target_parallel_codegen.cpp b/clang/test/OpenMP/target_parallel_codegen.cpp
index 7270bf7..0cead45 100644
--- a/clang/test/OpenMP/target_parallel_codegen.cpp
+++ b/clang/test/OpenMP/target_parallel_codegen.cpp
@@ -528,7 +528,7 @@
 // CHECK-64:       store i32 %{{.+}}, i32* [[B_ADDR]],
 // CHECK-64:       [[B_CVAL:%.+]] = load i[[SZ]], i[[SZ]]* [[B_CADDR]],
 
-// CHECK-32:       store i32 %{{.+}}, i32* %vla_expr
+// CHECK-32:       store i32 %{{.+}}, i32* %__vla_expr
 // CHECK-32:       store i32 %{{.+}}, i32* [[B_ADDR:%.+]],
 // CHECK-32:       [[B_CVAL:%.+]] = load i[[SZ]], i[[SZ]]* [[B_ADDR]],