This patch makes TARGET_VECTORIZE_VEC_PERM_CONST_OK take the permute
vector in the form of a vec_perm_indices instead of an unsigned char *.
It follows on from the recent patch that did the same in target-independent
code.

It was easy to make ARM and AArch64 use vec_perm_indices internally
as well, and converting AArch64 helps with SVE.  I did try doing the same
for the other ports, but the surgery needed was much more invasive and
much less obviously correct.

2017-09-22  Richard Sandiford  <richard.sandifird@linaro.org>

gcc/
	* target.def (vec_perm_const_ok): Change sel parameter to
	vec_perm_indices.
	* optabs-query.c (can_vec_perm_p): Update accordingly.
	* doc/tm.texi: Regenerate.
	* config/aarch64/aarch64.c (expand_vec_perm_d): Change perm to
	auto_vec_perm_indices and remove separate nelt field.
	(aarch64_evpc_trn, aarch64_evpc_uzp, aarch64_evpc_zip)
	(aarch64_evpc_ext, aarch64_evpc_rev, aarch64_evpc_dup)
	(aarch64_evpc_tbl, aarch64_expand_vec_perm_const_1)
	(aarch64_expand_vec_perm_const): Update accordingly.
	(aarch64_vectorize_vec_perm_const_ok): Likewise.  Change sel
	to vec_perm_indices.
	* config/arm/arm.c (expand_vec_perm_d): Change perm to
	auto_vec_perm_indices and remove separate nelt field.
	(arm_evpc_neon_vuzp, arm_evpc_neon_vzip, arm_evpc_neon_vrev)
	(arm_evpc_neon_vtrn, arm_evpc_neon_vext, arm_evpc_neon_vtbl)
	(arm_expand_vec_perm_const_1, arm_expand_vec_perm_const): Update
	accordingly.
	(arm_vectorize_vec_perm_const_ok): Likewise.  Change sel
	to vec_perm_indices.
	* config/i386/i386.c (ix86_vectorize_vec_perm_const_ok): Change
	sel to vec_perm_indices.
	* config/ia64/ia64.c (ia64_vectorize_vec_perm_const_ok): Likewise.
	* config/mips/mips.c (mips_vectorize_vec_perm_const_ok): Likewise.
	* config/powerpcspe/powerpcspe.c (rs6000_vectorize_vec_perm_const_ok):
	Likewise.
	* config/rs6000/rs6000.c (rs6000_vectorize_vec_perm_const_ok):
	Likewise.

From-SVN: r253148