match.pd ((x | y) & ~x -> y & ~x, (x & y) | ~x -> y | ~x): New simplifications.

2015-05-22  Marc Glisse  <marc.glisse@inria.fr>

gcc/
	* match.pd ((x | y) & ~x -> y & ~x, (x & y) | ~x -> y | ~x): New
	simplifications.
gcc/testsuite/
	* gcc.dg/nand.c: New testcase.

From-SVN: r223587