Hello!

This patch just adds missing popcounthi2 insn and splitter to enable
POPCNTW generation from _builtin_popcount builtin with zero-extended
unsigned short argument.

2016-12-19  Uros Bizjak  <ubizjak@gmail.com>

    * config/i386/i386.md (*popcounthi2_1): New insn_and_split pattern.

testsuite/ChangeLog:

2016-12-19  Uros Bizjak  <ubizjak@gmail.com>

    * gcc.target/i386/pr59874-3.c: New test.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Committed to mainline SVN.

Uros.