tree-optimization/117502 - VMAT_STRIDED_SLP vs VMAT_ELEMENTWISE when considering...

The following treats both the same when considering to use gather or
scatter for single-element interleaving accesses.

This will cause

FAIL: gcc.target/aarch64/sve/sve_iters_low_2.c scan-tree-dump-not vect "LOOP VECTORIZED"

where we now vectorize the loop with VNx4QI, I'll leave it to ARM folks
to investigate whether that's OK and to adjust the testcase or to see
where to adjust things to make the testcase not vectorized again.  The
original fix for which the testcase was introduced is still efffective.

	PR tree-optimization/117502
	* tree-vect-stmts.cc (get_group_load_store_type): Also consider
	VMAT_STRIDED_SLP when checking to use gather/scatter for
	single-element interleaving access.
	* tree-vect-loop.cc (update_epilogue_loop_vinfo): STMT_VINFO_STRIDED_P
	can be classified as VMAT_GATHER_SCATTER, so update DR_REF for
	those as well.

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 6cfce5aa7e1e9812d22a0e4c92c18b4e9eb90931..f50ee2e958ef470c11e4738e522b4f9ed13941fc 100644 (file)
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -12295,6 +12295,7 @@ update_epilogue_loop_vinfo (class loop *epilogue, tree advance)
         refs that get_load_store_type classified as VMAT_GATHER_SCATTER.  */
       auto vstmt_vinfo = vect_stmt_to_vectorize (stmt_vinfo);
       if (STMT_VINFO_MEMORY_ACCESS_TYPE (vstmt_vinfo) == VMAT_GATHER_SCATTER
+         || STMT_VINFO_STRIDED_P (vstmt_vinfo)
          || STMT_VINFO_GATHER_SCATTER_P (vstmt_vinfo))
        {
          /* ???  As we copy epilogues from the main loop incremental

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 666e0491a9e8eac190d9f6544f734d3ed33f1841..f77a223b0c4fc8e576de459c3c1163a31add1cea 100644 (file)
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -2274,7 +2274,8 @@ get_group_load_store_type (vec_info *vinfo, stmt_vec_info stmt_info,
      on nearby locations.  Or, even if it's a win over scalar code,
      it might not be a win over vectorizing at a lower VF, if that
      allows us to use contiguous accesses.  */
-  if (*memory_access_type == VMAT_ELEMENTWISE
+  if ((*memory_access_type == VMAT_ELEMENTWISE
+       || *memory_access_type == VMAT_STRIDED_SLP)
       && single_element_p
       && loop_vinfo
       && vect_use_strided_gather_scatters_p (stmt_info, loop_vinfo,