match.pd (A + (B vcmp C ? 1 : 0) -> A - (B vcmp C)): Apply for boolean vector with vector mode only.

gcc/

	* match.pd (A + (B vcmp C ? 1 : 0) -> A - (B vcmp C)): Apply
	for boolean vector with vector mode only.
	(A - (B vcmp C ? 1 : 0) -> A + (B vcmp C)): Likewise.

gcc/testsuite/

	* gcc.target/i386/pr70251.c: New test.

From-SVN: r234283