diff --git a/clang/test/Driver/gcc-toolchain.cpp b/clang/test/Driver/gcc-toolchain.cpp
index 8bb391f19eac5b..4bd658315a447f 100644
--- a/clang/test/Driver/gcc-toolchain.cpp
+++ b/clang/test/Driver/gcc-toolchain.cpp
@@ -1,12 +1,14 @@
 // Test that gcc-toolchain option is working correctly
 //
+/// Without --rtlib=libgcc the driver may pick clang_rt.crtbegin.o if
+/// -DCLANG_DEFAULT_RTLIB=compiler-rt.
 // RUN: %clangxx -no-canonical-prefixes %s -### -o %t --target=x86_64-linux-gnu \
-// RUN:   --gcc-toolchain=%S/Inputs/ubuntu_14.04_multiarch_tree/usr -stdlib=libstdc++ 2>&1 | \
+// RUN:   --gcc-toolchain=%S/Inputs/ubuntu_14.04_multiarch_tree/usr -stdlib=libstdc++ --rtlib=libgcc 2>&1 | \
 // RUN:   FileCheck %s
 //
 // Additionally check that the legacy spelling of the flag works.
 // RUN: %clangxx -no-canonical-prefixes %s -### -o %t --target=x86_64-linux-gnu \
-// RUN:   --gcc-toolchain=%S/Inputs/ubuntu_14.04_multiarch_tree/usr -stdlib=libstdc++ 2>&1 | \
+// RUN:   -gcc-toolchain %S/Inputs/ubuntu_14.04_multiarch_tree/usr -stdlib=libstdc++ --rtlib=libgcc 2>&1 | \
 // RUN:   FileCheck %s
 //
 // Test for header search toolchain detection.