Use vec<> for constant permute masks

This patch makes can_vec_perm_p & co. take a vec<>, wrapped in new
typedefs vec_perm_indices and auto_vec_perm_indices.  There are two
reasons for doing this for SVE:

(1) it means that the number of elements is bundled with the elements
    themselves, and is obviously constant.

(2) it makes it easier to change the "unsigned char" element type to
    something wider.

Changing the target hook is left as follow-on work.

2017-09-14  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* target.h (vec_perm_indices): New typedef.
	(auto_vec_perm_indices): Likewise.
	* optabs-query.h: Include target.h
	(can_vec_perm_p): Take a vec_perm_indices *.
	* optabs-query.c (can_vec_perm_p): Likewise.
	(can_mult_highpart_p): Update accordingly.  Use auto_vec_perm_indices.
	* tree-ssa-forwprop.c (simplify_vector_constructor): Likewise.
	* tree-vect-generic.c (lower_vec_perm): Likewise.
	* tree-vect-data-refs.c (vect_grouped_store_supported): Likewise.
	(vect_grouped_load_supported): Likewise.
	(vect_shift_permute_load_chain): Likewise.
	(vect_permute_store_chain): Use auto_vec_perm_indices.
	(vect_permute_load_chain): Likewise.
	* fold-const.c (fold_vec_perm): Take vec_perm_indices.
	(fold_ternary_loc): Update accordingly.  Use auto_vec_perm_indices.
	Update uses of can_vec_perm_p.
	* tree-vect-loop.c (calc_vec_perm_mask_for_shift): Replace the
	mode with a number of elements.  Take a vec_perm_indices *.
	(vect_create_epilog_for_reduction): Update accordingly.
	Use auto_vec_perm_indices.
	(have_whole_vector_shift): Likewise.  Update call to can_vec_perm_p.
	* tree-vect-slp.c (vect_build_slp_tree_1): Likewise.
	(vect_transform_slp_perm_load): Likewise.
	(vect_schedule_slp_instance): Use auto_vec_perm_indices.
	* tree-vectorizer.h (vect_gen_perm_mask_any): Take a vec_perm_indices.
	(vect_gen_perm_mask_checked): Likewise.
	* tree-vect-stmts.c (vect_gen_perm_mask_any): Take a vec_perm_indices.
	(vect_gen_perm_mask_checked): Likewise.
	(vectorizable_mask_load_store): Use auto_vec_perm_indices.
	(vectorizable_store): Likewise.
	(vectorizable_load): Likewise.
	(perm_mask_for_reverse): Likewise.  Update call to can_vec_perm_p.
	(vectorizable_bswap): Likewise.

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

From-SVN: r252761

1 files changed, 13 insertions, 12 deletions

diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 32ca6af..32174fe 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -873,15 +873,16 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
   if (alt_stmt_code != ERROR_MARK
       && TREE_CODE_CLASS (alt_stmt_code) != tcc_reference)
     {
-      unsigned char *sel
-	= XALLOCAVEC (unsigned char, TYPE_VECTOR_SUBPARTS (vectype));
-      for (i = 0; i < TYPE_VECTOR_SUBPARTS (vectype); ++i)
+      unsigned int count = TYPE_VECTOR_SUBPARTS (vectype);
+      auto_vec_perm_indices sel (count);
+      for (i = 0; i < count; ++i)
 	{
-	  sel[i] = i;
+	  unsigned int elt = i;
 	  if (gimple_assign_rhs_code (stmts[i % group_size]) == alt_stmt_code)
-	    sel[i] += TYPE_VECTOR_SUBPARTS (vectype);
+	    elt += count;
+	  sel.quick_push (elt);
 	}
-      if (!can_vec_perm_p (TYPE_MODE (vectype), false, sel))
+      if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
 	{
 	  for (i = 0; i < group_size; ++i)
 	    if (gimple_assign_rhs_code (stmts[i]) == alt_stmt_code)
@@ -3486,7 +3487,6 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
   int group_size = SLP_INSTANCE_GROUP_SIZE (slp_node_instance);
   int mask_element;
-  unsigned char *mask;
   machine_mode mode;
 
   if (!STMT_VINFO_GROUPED_ACCESS (stmt_info))
@@ -3502,7 +3502,8 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
     (int_mode_for_mode (TYPE_MODE (TREE_TYPE (vectype))).require (), 1);
   mask_type = get_vectype_for_scalar_type (mask_element_type);
   nunits = TYPE_VECTOR_SUBPARTS (vectype);
-  mask = XALLOCAVEC (unsigned char, nunits);
+  auto_vec_perm_indices mask (nunits);
+  mask.quick_grow (nunits);
 
   /* Initialize the vect stmts of NODE to properly insert the generated
      stmts later.  */
@@ -3577,7 +3578,7 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
 	  if (index == nunits)
 	    {
 	      if (! noop_p
-		  && ! can_vec_perm_p (mode, false, mask))
+		  && ! can_vec_perm_p (mode, false, &mask))
 		{
 		  if (dump_enabled_p ())
 		    {
@@ -3730,15 +3731,15 @@ vect_schedule_slp_instance (slp_tree node, slp_instance instance,
       enum tree_code code0 = gimple_assign_rhs_code (stmt);
       enum tree_code ocode = ERROR_MARK;
       gimple *ostmt;
-      unsigned char *mask = XALLOCAVEC (unsigned char, group_size);
+      auto_vec_perm_indices mask (group_size);
       FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, ostmt)
 	if (gimple_assign_rhs_code (ostmt) != code0)
 	  {
-	    mask[i] = 1;
+	    mask.quick_push (1);
 	    ocode = gimple_assign_rhs_code (ostmt);
 	  }
 	else
-	  mask[i] = 0;
+	  mask.quick_push (0);
       if (ocode != ERROR_MARK)
 	{
 	  vec<gimple *> v0;