[SYCL] Generalize group_algorithm helpers (#12726)

This commit generalizes two helper functions in group_algorithm.hpp to
make it so they can also handle non-uniform groups.

---------

Signed-off-by: Larsen, Steffen <steffen.larsen@intel.com>

Author: steffenlarsen

sycl/include/sycl/group_algorithm.hpp

@@ -59,42 +59,25 @@ template <> inline id<3> linear_id_to_id(range<3> r, size_t linear_id) {
 }
 
 // ---- get_local_linear_range
-template <typename Group> size_t get_local_linear_range(Group g);
-template <> inline size_t get_local_linear_range<group<1>>(group<1> g) {
-  return g.get_local_range(0);
-}
-template <> inline size_t get_local_linear_range<group<2>>(group<2> g) {
-  return g.get_local_range(0) * g.get_local_range(1);
-}
-template <> inline size_t get_local_linear_range<group<3>>(group<3> g) {
-  return g.get_local_range(0) * g.get_local_range(1) * g.get_local_range(2);
-}
-template <>
-inline size_t get_local_linear_range<sycl::sub_group>(sycl::sub_group g) {
-  return g.get_local_range()[0];
+template <typename Group> inline auto get_local_linear_range(Group g) {
+  auto local_range = g.get_local_range();
+  auto result = local_range[0];
+  for (size_t i = 1; i < Group::dimensions; ++i)
+    result *= local_range[i];
+  return result;
 }
 
 // ---- get_local_linear_id
-template <typename Group>
-inline typename Group::linear_id_type get_local_linear_id(Group g);
-
+template <typename Group> inline auto get_local_linear_id(Group g) {
 #ifdef __SYCL_DEVICE_ONLY__
-#define __SYCL_GROUP_GET_LOCAL_LINEAR_ID(D)                                    \
-  template <>                                                                  \
-  inline group<D>::linear_id_type get_local_linear_id<group<D>>(group<D>) {    \
-    nd_item<D> it = sycl::detail::Builder::getNDItem<D>();                     \
-    return it.get_local_linear_id();                                           \
+  if constexpr (std::is_same_v<Group, group<1>> ||
+                std::is_same_v<Group, group<2>> ||
+                std::is_same_v<Group, group<3>>) {
+    auto it = sycl::detail::Builder::getNDItem<Group::dimensions>();
+    return it.get_local_linear_id();
   }
-__SYCL_GROUP_GET_LOCAL_LINEAR_ID(1);
-__SYCL_GROUP_GET_LOCAL_LINEAR_ID(2);
-__SYCL_GROUP_GET_LOCAL_LINEAR_ID(3);
-#undef __SYCL_GROUP_GET_LOCAL_LINEAR_ID
 #endif // __SYCL_DEVICE_ONLY__
-
-template <>
-inline sycl::sub_group::linear_id_type
-get_local_linear_id<sycl::sub_group>(sycl::sub_group g) {
-  return g.get_local_id()[0];
+  return g.get_local_linear_id();
 }
 
 // ---- is_native_op