message: Update datalayout constant copied in XLA to match LLVM r308675
  This may break the CUDA backend until the LLVM revision is updated.
diff: @@ -81,7 +81,7 @@ const char* kTargetTriple = "nvptx64-nvidia-cuda";
  // The data layout of the emitted module. Copied from computeDataLayout in
  // NVPTXTargetMachine.cpp.
  -const char* kDataLayout = "e-i64:64-v16:16-v32:32-n16:32:64";
  +const char* kDataLayout = "e-i64:64-i128:128-v16:16-v32:32-n16:32:64";
  // Any address of a variable residing in global memory or returned by one of the
  // memory allocation routines from the driver or runtime API is always aligned
  