diff --git a/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h b/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h
index 47e12d20bed..74606208870 100644
--- a/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h
+++ b/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_merge.h
@@ -194,19 +194,19 @@ __serial_merge(const _Rng1& __rng1, const _Rng2& __rng2, _Rng3& __rng3, _Index _
     {
         //copying a residual of the second seq
         const _Index __n = std::min<_Index>(__n2 - __start2, __chunk);
-        for (std::uint8_t __i = 0; __i < __n; ++__i)
+        for (_Index __i = 0; __i < __n; ++__i)
             __rng3[__start3 + __i] = __rng2[__start2 + __i];
     }
     else if (__start2 >= __n2)
     {
         //copying a residual of the first seq
         const _Index __n = std::min<_Index>(__n1 - __start1, __chunk);
-        for (std::uint8_t __i = 0; __i < __n; ++__i)
+        for (_Index __i = 0; __i < __n; ++__i)
             __rng3[__start3 + __i] = __rng1[__start1 + __i];
     }
     else
     {
-        for (std::uint8_t __i = 0; __i < __chunk && __start1 < __n1 && __start2 < __n2; ++__i)
+        for (_Index __i = 0; __i < __chunk && __start1 < __n1 && __start2 < __n2; ++__i)
         {
             const auto& __val1 = __rng1[__start1];
             const auto& __val2 = __rng2[__start2];