Add support for masked load/store_lanes

Add support for masked load/store_lanes

This patch adds support for vectorising groups of IFN_MASK_LOADs
and IFN_MASK_STOREs using conditional load/store-lanes instructions.
This requires new internal functions to represent the result
(IFN_MASK_{LOAD,STORE}_LANES), as well as associated optabs.

The normal IFN_{LOAD,STORE}_LANES functions are const operations
that logically just perform the permute: the load or store is
encoded as a MEM operand to the call statement.  In contrast,
the IFN_MASK_{LOAD,STORE}_LANES functions use the same kind of
interface as IFN_MASK_{LOAD,STORE}, since the memory is only
conditionally accessed.

The AArch64 patterns were added as part of the main LD[234]/ST[234] patch.

2018-01-13  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* doc/md.texi (vec_mask_load_lanes@var{m}@var{n}): Document.
	(vec_mask_store_lanes@var{m}@var{n}): Likewise.
	* optabs.def (vec_mask_load_lanes_optab): New optab.
	(vec_mask_store_lanes_optab): Likewise.
	* internal-fn.def (MASK_LOAD_LANES): New internal function.
	(MASK_STORE_LANES): Likewise.
	* internal-fn.c (mask_load_lanes_direct): New macro.
	(mask_store_lanes_direct): Likewise.
	(expand_mask_load_optab_fn): Handle masked operations.
	(expand_mask_load_lanes_optab_fn): New macro.
	(expand_mask_store_optab_fn): Handle masked operations.
	(expand_mask_store_lanes_optab_fn): New macro.
	(direct_mask_load_lanes_optab_supported_p): Likewise.
	(direct_mask_store_lanes_optab_supported_p): Likewise.
	* tree-vectorizer.h (vect_store_lanes_supported): Take a masked_p
	parameter.
	(vect_load_lanes_supported): Likewise.
	* tree-vect-data-refs.c (strip_conversion): New function.
	(can_group_stmts_p): Likewise.
	(vect_analyze_data_ref_accesses): Use it instead of checking
	for a pair of assignments.
	(vect_store_lanes_supported): Take a masked_p parameter.
	(vect_load_lanes_supported): Likewise.
	* tree-vect-loop.c (vect_analyze_loop_2): Update calls to
	vect_store_lanes_supported and vect_load_lanes_supported.
	* tree-vect-slp.c (vect_analyze_slp_instance): Likewise.
	* tree-vect-stmts.c (get_group_load_store_type): Take a masked_p
	parameter.  Don't allow gaps for masked accesses.
	Use vect_get_store_rhs.  Update calls to vect_store_lanes_supported
	and vect_load_lanes_supported.
	(get_load_store_type): Take a masked_p parameter and update
	call to get_group_load_store_type.
	(vectorizable_store): Update call to get_load_store_type.
	Handle IFN_MASK_STORE_LANES.
	(vectorizable_load): Update call to get_load_store_type.
	Handle IFN_MASK_LOAD_LANES.

gcc/testsuite/
	* gcc.dg/vect/vect-ooo-group-1.c: New test.
	* gcc.target/aarch64/sve/mask_struct_load_1.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_1_run.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_2.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_2_run.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_3.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_3_run.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_4.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_5.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_6.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_7.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_load_8.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_store_1.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_store_1_run.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_store_2.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_store_2_run.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_store_3.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_store_3_run.c: Likewise.
	* gcc.target/aarch64/sve/mask_struct_store_4.c: Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r256620