re PR target/68647 (__builtin_popcountll doesn't generate popcnt instructions when targeting -mpopcnt on x86_32)

	PR target/68647
	* optabs.c (expand_doubleword_popcount, expand_doubleword_parity):
	New functions.
	(expand_unop): Use them.

	* gcc.target/i386/pr68647.c: New test.

From-SVN: r231201