[gcc r15-1097] Fix fold-left reduction vectorization with multiple stmt copies

[Richard Biener via Gcc-cvs]

https://gcc.gnu.org/g:dd6f942c266533b2f72610f354bc9184f8276beb

commit r15-1097-gdd6f942c266533b2f72610f354bc9184f8276beb
Author: Richard Biener <rguent...@suse.de>
Date:   Fri Jun 7 09:41:11 2024 +0200

    Fix fold-left reduction vectorization with multiple stmt copies
    
    There's a typo when code generating the mask operand for conditional
    fold-left reductions in the case we have multiple stmt copies.  The
    latter is now allowed for SLP and possibly disabled for non-SLP by
    accident.
    
    This fixes the observed run-FAIL for
    gcc.dg/vect/vect-cond-reduc-in-order-2-signed-zero.c with AVX512
    and 256bit sized vectors.
    
            * tree-vect-loop.cc (vectorize_fold_left_reduction): Fix
            mask vector operand indexing.

Diff:
---
 gcc/tree-vect-loop.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index ceb92156b58..028692614bb 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -7217,7 +7217,7 @@ vectorize_fold_left_reduction (loop_vec_info loop_vinfo,
       if (LOOP_VINFO_FULLY_MASKED_P (loop_vinfo))
        mask = vect_get_loop_mask (loop_vinfo, gsi, masks, vec_num, vectype_in, 
i);
       else if (is_cond_op)
-       mask = vec_opmask[0];
+       mask = vec_opmask[i];
       if (LOOP_VINFO_FULLY_WITH_LENGTH_P (loop_vinfo))
        {
          len = vect_get_loop_len (loop_vinfo, gsi, lens, vec_num, vectype_in,