rs6000.c (altivec_expand_vec_perm_const): Reverse meaning of merge-high and merge-low masks for little endian...

gcc:

2013-10-22  Bill Schmidt  <wschmidt@vnet.ibm.com>

	* config/rs6000/rs6000.c (altivec_expand_vec_perm_const): Reverse
	meaning of merge-high and merge-low masks for little endian; avoid
	use of vector-pack masks for little endian for mismatched modes.

gcc/testsuite:

2013-10-22  Bill Schmidt  <wschmidt@vnet.ibm.com>

	* gcc.target/powerpc/altivec-perm-1.c: Move the two vector pack
	tests into...
	* gcc.target/powerpc/altivec-perm-3.c: ...this new test, which is
	restricted to big-endian targets.

From-SVN: r203930