[SYCL] [FPGA] Manually revert header change of variadic template argument list (#4260)

The previous patch #3957 was a
prerequisite change for the upcoming FPGA latency control feature. 
Revert due to a late change to the proposed use model API.

Author: shuoniu-intel

sycl/include/sycl/ext/intel/fpga_lsu.hpp

@@ -20,27 +20,24 @@ constexpr uint8_t CACHE = 0x2;
 constexpr uint8_t STATICALLY_COALESCE = 0x4;
 constexpr uint8_t PREFETCH = 0x8;
 
-struct burst_coalesce_impl_id;
-template <int32_t _N>
-struct burst_coalesce_impl : std::integral_constant<int32_t, _N> {
-  using type_id = burst_coalesce_impl_id;
+template <int32_t _N> struct burst_coalesce_impl {
+  static constexpr int32_t value = _N;
+  static constexpr int32_t default_value = 0;
 };
 
-struct cache_id;
-template <int32_t _N> struct cache : std::integral_constant<int32_t, _N> {
-  using type_id = cache_id;
+template <int32_t _N> struct cache {
+  static constexpr int32_t value = _N;
+  static constexpr int32_t default_value = 0;
 };
 
-struct prefetch_impl_id;
-template <int32_t _N>
-struct prefetch_impl : std::integral_constant<int32_t, _N> {
-  using type_id = prefetch_impl_id;
+template <int32_t _N> struct prefetch_impl {
+  static constexpr int32_t value = _N;
+  static constexpr int32_t default_value = 0;
 };
 
-struct statically_coalesce_impl_id;
-template <int32_t _N>
-struct statically_coalesce_impl : std::integral_constant<int32_t, _N> {
-  using type_id = statically_coalesce_impl_id;
+template <int32_t _N> struct statically_coalesce_impl {
+  static constexpr int32_t value = _N;
+  static constexpr int32_t default_value = 1;
 };
 
 template <bool _B> using burst_coalesce = burst_coalesce_impl<_B>;
@@ -81,21 +78,21 @@ template <class... _mem_access_params> class lsu final {
 
 private:
   static constexpr int32_t _burst_coalesce_val =
-      _GetValue<burst_coalesce_impl<0>, _mem_access_params...>::value;
+      _GetValue<burst_coalesce_impl, _mem_access_params...>::value;
   static constexpr uint8_t _burst_coalesce =
       _burst_coalesce_val == 1 ? BURST_COALESCE : 0;
 
   static constexpr int32_t _cache_val =
-      _GetValue<cache<0>, _mem_access_params...>::value;
+      _GetValue<cache, _mem_access_params...>::value;
   static constexpr uint8_t _cache = (_cache_val > 0) ? CACHE : 0;
 
   static constexpr int32_t _statically_coalesce_val =
-      _GetValue<statically_coalesce_impl<1>, _mem_access_params...>::value;
+      _GetValue<statically_coalesce_impl, _mem_access_params...>::value;
   static constexpr uint8_t _dont_statically_coalesce =
       _statically_coalesce_val == 0 ? STATICALLY_COALESCE : 0;
 
   static constexpr int32_t _prefetch_val =
-      _GetValue<prefetch_impl<0>, _mem_access_params...>::value;
+      _GetValue<prefetch_impl, _mem_access_params...>::value;
   static constexpr uint8_t _prefetch = _prefetch_val ? PREFETCH : 0;
 
   static_assert(_cache_val >= 0, "cache size parameter must be non-negative");

sycl/include/sycl/ext/intel/fpga_utils.hpp

@@ -17,25 +17,18 @@ namespace sycl {
 namespace ext {
 namespace intel {
 
-template <class _D, class _T>
-struct _MatchType : std::is_same<typename _D::type_id, typename _T::type_id> {};
+template <template <int32_t> class _Type, class _T>
+struct _MatchType : std::is_same<_Type<_T::value>, _T> {};
 
-template <class _D, class... _T> struct _GetValue;
-
-template <class _D>
-struct _GetValue<_D> : std::integral_constant<decltype(_D::value), _D::value> {
+template <template <int32_t> class _Type, class... _T> struct _GetValue {
+  static constexpr auto value = _Type<0>::default_value;
 };
 
-template <class _D, class _T1, class... _T> struct _GetValue<_D, _T1, _T...> {
-  template <class _D2, class _T12, class _Enable = void>
-  struct impl : std::integral_constant<decltype(_D::value),
-                                       _GetValue<_D, _T...>::value> {};
-
-  template <class _D2, class _T12>
-  struct impl<_D2, _T12, std::enable_if_t<_MatchType<_D2, _T12>::value>>
-      : std::integral_constant<decltype(_D::value), _T1::value> {};
-
-  static constexpr auto value = impl<_D, _T1>::value;
+template <template <int32_t> class _Type, class _T1, class... _T>
+struct _GetValue<_Type, _T1, _T...> {
+  static constexpr auto value =
+      detail::conditional_t<_MatchType<_Type, _T1>::value, _T1,
+                            _GetValue<_Type, _T...>>::value;
 };
 } // namespace intel
 } // namespace ext