re PR tree-optimization/68553 (gcc.dg/vect/pr68445.c FAILs)

2015-11-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/68553
	* tree-vect-slp.c (vect_create_mask_and_perm): Skip VEC_PERM_EXPR
	generation for 1:1 permutations.
	(vect_transform_slp_perm_load): Detect 1:1 permutations.

From-SVN: r231006

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e9fbabf667172df8dc5a5fce38d6177cdfef5e14..baf76d5f19e8270ace2c4b5569b60e50d76d0695 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2015-11-27  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/68553
+       * tree-vect-slp.c (vect_create_mask_and_perm): Skip VEC_PERM_EXPR
+       generation for 1:1 permutations.
+       (vect_transform_slp_perm_load): Detect 1:1 permutations.
+
 2015-11-27  Bernd Schmidt  <bschmidt@redhat.com>
 
        * gimple.h (nonbarrier_call_p): Declare.

diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index ded361a60e7944ffbfd3635e4600beda3a054fbd..5693ca5e35eb2fa8cad5e3b71d8bcccc4e4ba7d6 100644 (file)
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -3224,12 +3224,18 @@ vect_create_mask_and_perm (gimple *stmt,
       first_vec = dr_chain[first_vec_indx];
       second_vec = dr_chain[second_vec_indx];
 
-      /* Generate the permute statement.  */
-      perm_stmt = gimple_build_assign (perm_dest, VEC_PERM_EXPR,
-                                      first_vec, second_vec, mask);
-      data_ref = make_ssa_name (perm_dest, perm_stmt);
-      gimple_set_lhs (perm_stmt, data_ref);
-      vect_finish_stmt_generation (stmt, perm_stmt, gsi);
+      /* Generate the permute statement if necessary.  */
+      if (mask)
+       {
+         perm_stmt = gimple_build_assign (perm_dest, VEC_PERM_EXPR,
+                                          first_vec, second_vec, mask);
+         data_ref = make_ssa_name (perm_dest, perm_stmt);
+         gimple_set_lhs (perm_stmt, data_ref);
+         vect_finish_stmt_generation (stmt, perm_stmt, gsi);
+       }
+      else
+       /* If mask was NULL_TREE generate the requested identity transform.  */
+       perm_stmt = SSA_NAME_DEF_STMT (first_vec);
 
       /* Store the vector statement in NODE.  */
       SLP_TREE_VEC_STMTS (node)[stride_out * i + vect_stmts_counter]
@@ -3315,6 +3321,7 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
   int index = 0;
   int first_vec_index = -1;
   int second_vec_index = -1;
+  bool noop_p = true;
 
   for (int j = 0; j < unroll_factor; j++)
     {
@@ -3351,11 +3358,14 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
 
          gcc_assert (mask_element >= 0
                      && mask_element < 2 * nunits);
+         if (mask_element != index)
+           noop_p = false;
          mask[index++] = mask_element;
 
          if (index == nunits)
            {
-             if (!can_vec_perm_p (mode, false, mask))
+             if (! noop_p
+                 && ! can_vec_perm_p (mode, false, mask))
                {
                  if (dump_enabled_p ())
                    {
@@ -3371,11 +3381,16 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
 
              if (!analyze_only)
                {
-                 tree mask_vec, *mask_elts;
-                 mask_elts = XALLOCAVEC (tree, nunits);
-                 for (int l = 0; l < nunits; ++l)
-                   mask_elts[l] = build_int_cst (mask_element_type, mask[l]);
-                 mask_vec = build_vector (mask_type, mask_elts);
+                 tree mask_vec = NULL_TREE;
+                 
+                 if (! noop_p)
+                   {
+                     tree *mask_elts = XALLOCAVEC (tree, nunits);
+                     for (int l = 0; l < nunits; ++l)
+                       mask_elts[l] = build_int_cst (mask_element_type,
+                                                     mask[l]);
+                     mask_vec = build_vector (mask_type, mask_elts);
+                   }
 
                  if (second_vec_index == -1)
                    second_vec_index = first_vec_index;
@@ -3388,6 +3403,7 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
              index = 0;
              first_vec_index = -1;
              second_vec_index = -1;
+             noop_p = true;
            }
        }
     }