Fix valgrind warning for gcc builds.

Sorry, I don't understand why the warning is generated (a gcc
bug?). Anyhow, the change should improve readablity. No functionality
change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199214 91177308-0d34-0410-b5e6-96231b3b80d8