Prevent unused warning in non-assert builds (introduced in r310014).
Prevent unused warning in non-assert builds (introduced in r310014).

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@310022 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 2801a44d3fc617cd794c0ac1dbf1934620b27480)

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm