message: Bump LLVM to r317519, which includes fastmath API changes.
diff: @@ -573,11 +573,11 @@ def tf_workspace(path_prefix="", tf_repo_name=""):
  temp_workaround_http_archive(
  name = "llvm",
  urls = [
  - "https://mirror.bazel.build/github.com/llvm-mirror/llvm/archive/bb3c660e87f59abb665570a31b01ab125ec4c10e.tar.gz",
  - "https://github.com/llvm-mirror/llvm/archive/bb3c660e87f59abb665570a31b01ab125ec4c10e.tar.gz",
  + "https://mirror.bazel.build/github.com/llvm-mirror/llvm/archive/618cf290880ae9cd87b4bbf6c9b1759476f422eb.tar.gz",
  + "https://github.com/llvm-mirror/llvm/archive/618cf290880ae9cd87b4bbf6c9b1759476f422eb.tar.gz",
  ],
  - sha256 = "caab6d7978e6771cb4e9b5b89607c5370de8aa642913c6c14e892468194c94e4",
  - strip_prefix = "llvm-bb3c660e87f59abb665570a31b01ab125ec4c10e",
  + sha256 = "ec2e032e58372c614c41b539c0309baa91843c30d7a9c6dee647dcd24be02e3c",
  + strip_prefix = "llvm-618cf290880ae9cd87b4bbf6c9b1759476f422eb",
  build_file = str(Label("//third_party/llvm:llvm.BUILD")),
  repository = tf_repo_name,
  )
  