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, 10 insertions, 9 deletions

diff --git a/gcc/optabs-query.c b/gcc/optabs-query.c
index 81b1bd9..ced6f57 100644
--- a/gcc/optabs-query.c
+++ b/gcc/optabs-query.c
@@ -353,8 +353,7 @@ can_conditionally_move_p (machine_mode mode)
    zeroes; this case is not dealt with here.  */
 
 bool
-can_vec_perm_p (machine_mode mode, bool variable,
-		const unsigned char *sel)
+can_vec_perm_p (machine_mode mode, bool variable, vec_perm_indices *sel)
 {
   machine_mode qimode;
 
@@ -368,7 +367,7 @@ can_vec_perm_p (machine_mode mode, bool variable,
       if (direct_optab_handler (vec_perm_const_optab, mode) != CODE_FOR_nothing
 	  && (sel == NULL
 	      || targetm.vectorize.vec_perm_const_ok == NULL
-	      || targetm.vectorize.vec_perm_const_ok (mode, sel)))
+	      || targetm.vectorize.vec_perm_const_ok (mode, &(*sel)[0])))
 	return true;
     }
 
@@ -460,7 +459,6 @@ int
 can_mult_highpart_p (machine_mode mode, bool uns_p)
 {
   optab op;
-  unsigned char *sel;
   unsigned i, nunits;
 
   op = uns_p ? umul_highpart_optab : smul_highpart_optab;
@@ -472,7 +470,6 @@ can_mult_highpart_p (machine_mode mode, bool uns_p)
     return 0;
 
   nunits = GET_MODE_NUNITS (mode);
-  sel = XALLOCAVEC (unsigned char, nunits);
 
   op = uns_p ? vec_widen_umult_even_optab : vec_widen_smult_even_optab;
   if (optab_handler (op, mode) != CODE_FOR_nothing)
@@ -480,9 +477,12 @@ can_mult_highpart_p (machine_mode mode, bool uns_p)
       op = uns_p ? vec_widen_umult_odd_optab : vec_widen_smult_odd_optab;
       if (optab_handler (op, mode) != CODE_FOR_nothing)
 	{
+	  auto_vec_perm_indices sel (nunits);
 	  for (i = 0; i < nunits; ++i)
-	    sel[i] = !BYTES_BIG_ENDIAN + (i & ~1) + ((i & 1) ? nunits : 0);
-	  if (can_vec_perm_p (mode, false, sel))
+	    sel.quick_push (!BYTES_BIG_ENDIAN
+			    + (i & ~1)
+			    + ((i & 1) ? nunits : 0));
+	  if (can_vec_perm_p (mode, false, &sel))
 	    return 2;
 	}
     }
@@ -493,9 +493,10 @@ can_mult_highpart_p (machine_mode mode, bool uns_p)
       op = uns_p ? vec_widen_umult_lo_optab : vec_widen_smult_lo_optab;
       if (optab_handler (op, mode) != CODE_FOR_nothing)
 	{
+	  auto_vec_perm_indices sel (nunits);
 	  for (i = 0; i < nunits; ++i)
-	    sel[i] = 2 * i + (BYTES_BIG_ENDIAN ? 0 : 1);
-	  if (can_vec_perm_p (mode, false, sel))
+	    sel.quick_push (2 * i + (BYTES_BIG_ENDIAN ? 0 : 1));
+	  if (can_vec_perm_p (mode, false, &sel))
 	    return 3;
 	}
     }