Solved by tom in post #4 
              
              
                Remind me what 
@torch.jit.script
def round_away_from_0(x):
    return torch.trunc(x + 0.5 * torch.sign(x))

does not do for you? 
Then you could use torch._C._jit_override_can_fuse_on_cpu(True) to get fusion on CPU (but you need LLVM for this to be built-in).