Attempts at speeding up StringTableBuilder

[Rafael Espíndola via llvm-commits]

On 17 October 2016 at 17:30, Rui Ueyama <ruiu at google.com> wrote:
> Is there any way to speed up using multiple threads? It seems doable to
> split a set of strings into multiple shards, do string merging for each
> shard, and then just concatenate the results.

Maybe, but it is not entirely clear that would be faster since it
would imply more string comparisons.

Cheers,
Rafael