Re: speed up verifying UTF-8

> Also, if SSE is accepted into the tree, then the C fallback is only important on platforms like PowerPC64 and Arm64, so we can make the tradeoff by testing those more carefully. I'll test on PowerPC soon.

I got around to testing on POWER8 / Linux / gcc 4.8.5 and found a regression in the mixed2 case in v11. v12 improves that at the cost of some improvement in the ascii case (5x vs. 8x).

master:
 chinese | mixed | ascii | mixed2
---------+-------+-------+--------
    2966 |  1525 |   871 |   1474

v11-0001:
 chinese | mixed | ascii | mixed2
---------+-------+-------+--------
    1030 |   644 |   102 |   1760

v12-0001:
 chinese | mixed | ascii | mixed2
---------+-------+-------+--------
     977 |   632 |   168 |   1113

--
John Naylor
EDB: http://www.enterprisedb.com