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[v2] tree-optimization/117502 - VMAT_STRIDED_SLP vs VMAT_ELEMENTWISE when considering gather

Message ID 20241111101349.9EAD03858C60@sourceware.org
State New
Headers show
Series [v2] tree-optimization/117502 - VMAT_STRIDED_SLP vs VMAT_ELEMENTWISE when considering gather | expand

Commit Message

Richard Biener Nov. 11, 2024, 10:13 a.m. UTC 
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.

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

	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.
---
 gcc/tree-vect-loop.cc  | 1 +
 gcc/tree-vect-stmts.cc | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 6cfce5aa7e1..f50ee2e958e 100644
--- 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 fa44e19f163..b09c016949f 100644
--- 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,