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[RFC] vect: verify that nelt is greater than one

Message ID 20230323051151.2982138-1-kevinl@rivosinc.com
State New
Headers show
Series [RFC] vect: verify that nelt is greater than one | expand

Commit Message

Kevin Lee March 23, 2023, 5:11 a.m. UTC 
This is a patch related to https://gcc.gnu.org/pipermail/gcc-patches/2023-March/613977.html, 
aiming for gcc14. Since the RISC-V target has vector modes (e.g. VNx1DImode)
with nelt smaller than 2, npat has to match with the nelt to create proper 
vec_perm_indices. 

I tested on x86_64-linux-gnu and didn't cause more failures, but wasn't sure if 
total_elem would be used in the rest of the function. Should there be additional
changes in the vect_grouped_store_supported? Thank you!

gcc/ChangeLog:
Kevin Lee <kevinl@rivosinc.com>
	* tree-vect-data-refs.cc (vect_grouped_store_supported): Check
if the nelt is greater than one.
---
 gcc/tree-vect-data-refs.cc | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/gcc/tree-vect-data-refs.cc b/gcc/tree-vect-data-refs.cc
index 8daf7bd7dd3..9c09cc973d0 100644
--- a/gcc/tree-vect-data-refs.cc
+++ b/gcc/tree-vect-data-refs.cc
@@ -5399,17 +5399,20 @@  vect_grouped_store_supported (tree vectype, unsigned HOST_WIDE_INT count)
 	  poly_uint64 nelt = GET_MODE_NUNITS (mode);
 
 	  /* The encoding has 2 interleaved stepped patterns.  */
-	  vec_perm_builder sel (nelt, 2, 3);
-	  sel.quick_grow (6);
+
+    unsigned int npat = known_gt(nelt, (unsigned int) 1) ? 2 : 1;
+    unsigned int total_elem = npat * 3;
+	  vec_perm_builder sel (nelt, npat, 3);
+	  sel.quick_grow (total_elem);
 	  for (i = 0; i < 3; i++)
 	    {
-	      sel[i * 2] = i;
-	      sel[i * 2 + 1] = i + nelt;
+	      sel[i * npat] = i;
+	      sel[i * npat + 1] = i + nelt;
 	    }
 	  vec_perm_indices indices (sel, 2, nelt);
 	  if (can_vec_perm_const_p (mode, mode, indices))
 	    {
-	      for (i = 0; i < 6; i++)
+	      for (i = 0; i < total_elem; i++)
 		sel[i] += exact_div (nelt, 2);
 	      indices.new_vector (sel, 2, nelt);
 	      if (can_vec_perm_const_p (mode, mode, indices))