diff --git a/gcc/testsuite/gcc.dg/vect/pr116985.c b/gcc/testsuite/gcc.dg/vect/pr116985.c
new file mode 100644
index 00000000000..e6dfdaf0fb5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr116985.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-options "--param=vect-partial-vector-usage=2 -O2" } */
+/* { dg-additional-options "-mavx512vbmi2" { target { i?86-*-* x86_64-*-* } } } */
+/* { dg-additional-options "-march=armv9-a" { target aarch64-*-* } } */
+
+signed int __attribute__ ((noipa))
+fn (signed int n,
+   signed char *restrict a,
+   signed char *restrict b,
+   signed char *restrict c,
+   signed char *restrict d)
+{
+  signed int res = 0;
+
+  for (int i = 0; i < n; ++i)
+    {
+      res += a[i] * b[i];
+      res += i + 1;
+      res += c[i] * d[i];
+    }
+  return res;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index ade72a5124f..025442aabc3 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -8916,6 +8916,7 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
 
   bool emulated_mixed_dot_prod = vect_is_emulated_mixed_dot_prod (stmt_info);
   unsigned num = vec_oprnds[reduc_index == 0 ? 1 : 0].length ();
+  unsigned mask_index = 0;
 
   for (unsigned i = 0; i < num; ++i)
     {
@@ -8954,7 +8955,8 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
 	      std::swap (vop[0], vop[1]);
 	    }
 	  tree mask = vect_get_loop_mask (loop_vinfo, gsi, masks,
-					  vec_num * ncopies, vectype_in, i);
+					  vec_num * ncopies, vectype_in,
+					  mask_index++);
 	  gcall *call = gimple_build_call_internal (cond_fn, 4, mask,
 						    vop[0], vop[1], vop[0]);
 	  new_temp = make_ssa_name (vec_dest, call);
@@ -8971,7 +8973,8 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
 	  if (masked_loop_p && mask_by_cond_expr)
 	    {
 	      tree mask = vect_get_loop_mask (loop_vinfo, gsi, masks,
-					      vec_num * ncopies, vectype_in, i);
+					      vec_num * ncopies, vectype_in,
+					      mask_index++);
 	      build_vect_cond_expr (code, vop, mask, gsi);
 	    }