implement AccIsEnabled

- the value of AccIsEnabled indicates whether an accelerator is enabled for a specific tag
- AccTags list which contains all tags
- EnabledAccTags contains all tags, where the related Acc is enabled
- isCpuTag returns true, if the related Acc is bounded the cpuplatform
- enable relaxed template template argument matching for Clang base compiler

cmake/alpakaCommon.cmake

@@ -194,6 +194,13 @@ else()
         endif()
     endif()
 
+    # C++17 relaxed template template argument matching is disabled by default until Clang 19
+    # https://github.com/llvm/llvm-project/commit/b86e0992bfa6
+    # https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#150
+    # for example, is required to create alpaka::EnabledAccTags
+    # the feature is implemented since Clang 4
+    alpaka_set_compiler_options(HOST_DEVICE target alpaka "$<$<AND:$<CXX_COMPILER_ID:Clang,AppleClang,IntelLLVM>>:SHELL:-frelaxed-template-template-args>")
+
     # Add debug optimization levels. CMake doesn't do this by default.
     # Note that -Og is the recommended gcc optimization level for debug mode but is equivalent to -O1 for clang (and its derivates).
     alpaka_set_compiler_options(HOST_DEVICE target alpaka "$<$<AND:$<CONFIG:Debug>,$<CXX_COMPILER_ID:GNU>,$<COMPILE_LANGUAGE:CXX>>:SHELL:-Og>"
@@ -570,6 +577,13 @@ if(alpaka_ACC_GPU_HIP_ENABLE)
             alpaka_set_compiler_options(HOST_DEVICE target alpaka "$<$<COMPILE_LANGUAGE:CXX>:-D__HIP_PLATFORM_HCC__>")
         endif()
 
+        # C++17 relaxed template template argument matching is disabled by default until Clang 19
+        # https://github.com/llvm/llvm-project/commit/b86e0992bfa6
+        # https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#150
+        # for example, is required to create alpaka::EnabledAccTags
+        # TODO(SimeonEhrig): restict HIP version, if first HIP version is release using Clang 19 
+        alpaka_set_compiler_options(HOST_DEVICE target alpaka "$<$<COMPILE_LANGUAGE:HIP>:SHELL:-frelaxed-template-template-args>")
+
         alpaka_compiler_option(HIP_KEEP_FILES "Keep all intermediate files that are generated during internal compilation steps 'CMakeFiles/<targetname>.dir'" OFF)
         if(alpaka_HIP_KEEP_FILES)
             alpaka_set_compiler_options(HOST_DEVICE target alpaka "$<$<COMPILE_LANGUAGE:HIP>:SHELL:-save-temps>")
@@ -630,6 +644,7 @@ if(alpaka_ACC_SYCL_ENABLE)
         alpaka_set_compiler_options(HOST_DEVICE target alpaka "-fsycl")
         target_link_options(alpaka INTERFACE "-fsycl")
         alpaka_set_compiler_options(HOST_DEVICE target alpaka "-sycl-std=2020")
+        alpaka_set_compiler_options(HOST_DEVICE target alpaka "-frelaxed-template-template-args")
 
         #-----------------------------------------------------------------------------------------------------------------
         # Determine SYCL targets

include/alpaka/acc/Tag.hpp

@@ -41,18 +41,32 @@ namespace alpaka
         struct TagToAcc;
     } // namespace trait
 
-    /// @brief maps an acc type to a tag type
-    /// @tparam TAcc alpaka acc type
+    //! \brief maps an acc type to a tag type
+    //! \tparam TAcc alpaka acc type
     template<typename TAcc>
     using AccToTag = typename trait::AccToTag<TAcc>::type;
 
-    /// @brief maps a tag type to an acc type
-    /// @tparam TTag alpaka tag type
-    /// @tparam TDim dimension of the mapped acc type
-    /// @tparam TIdx index type of the mapped acc type
+    //! \brief maps a tag type to an acc type
+    //! \tparam TTag alpaka tag type
+    //! \tparam TDim dimension of the mapped acc type
+    //! \tparam TIdx index type of the mapped acc type
     template<typename TTag, typename TDim, typename TIdx>
     using TagToAcc = typename trait::TagToAcc<TTag, TDim, TIdx>::type;
 
     template<typename TAcc, typename... TTag>
     inline constexpr bool accMatchesTags = (std::is_same_v<alpaka::AccToTag<TAcc>, TTag> || ...);
+
+    //! list of all available tags
+    using AccTags = std::tuple<
+        alpaka::TagCpuSerial,
+        alpaka::TagCpuThreads,
+        alpaka::TagCpuTbbBlocks,
+        alpaka::TagCpuOmp2Blocks,
+        alpaka::TagCpuOmp2Threads,
+        alpaka::TagGpuCudaRt,
+        alpaka::TagGpuHipRt,
+        alpaka::TagCpuSycl,
+        alpaka::TagFpgaSyclIntel,
+        alpaka::TagGpuSyclIntel>;
+
 } // namespace alpaka

include/alpaka/acc/TagAccIsEnabled.hpp

@@ -0,0 +1,36 @@
+#pragma once
+
+// include all Acc's because of the struct AccIsEnabled
+// if an acc is not include, it will be not enabled independent of the compiler flags
+#include "alpaka/acc/AccCpuOmp2Blocks.hpp"
+#include "alpaka/acc/AccCpuOmp2Threads.hpp"
+#include "alpaka/acc/AccCpuSerial.hpp"
+#include "alpaka/acc/AccCpuSycl.hpp"
+#include "alpaka/acc/AccCpuTbbBlocks.hpp"
+#include "alpaka/acc/AccCpuThreads.hpp"
+#include "alpaka/acc/AccFpgaSyclIntel.hpp"
+#include "alpaka/acc/AccGpuCudaRt.hpp"
+#include "alpaka/acc/AccGpuHipRt.hpp"
+#include "alpaka/dim/DimIntegralConst.hpp"
+#include "alpaka/meta/Filter.hpp"
+
+#include <type_traits>
+
+namespace alpaka
+{
+    //! \brief check if the accelerator is enabled for a given tag
+    //! \tparam TTag alpaka tag type
+    template<typename TTag, typename = void>
+    struct AccIsEnabled : std::false_type
+    {
+    };
+
+    template<typename TTag>
+    struct AccIsEnabled<TTag, std::void_t<TagToAcc<TTag, alpaka::DimInt<1>, int>>> : std::true_type
+    {
+    };
+
+    //! list of all tags where the related accelerator is enabled
+    using EnabledAccTags = alpaka::meta::Filter<AccTags, alpaka::AccIsEnabled>;
+
+} // namespace alpaka

include/alpaka/alpaka.hpp

@@ -23,6 +23,7 @@
 #include "alpaka/acc/AccGpuHipRt.hpp"
 #include "alpaka/acc/AccGpuSyclIntel.hpp"
 #include "alpaka/acc/Tag.hpp"
+#include "alpaka/acc/TagAccIsEnabled.hpp"
 #include "alpaka/acc/Traits.hpp"
 // atomic
 #include "alpaka/atomic/AtomicCpu.hpp"

test/unit/acc/src/AccTagTest.cpp

@@ -2,6 +2,10 @@
  * SPDX-License-Identifier: MPL-2.0
  */
 
+// Undefine ALPAKA_CI for this test, because the variable set the value of some acc types, like
+// AccCpuThreadsIfAvailableElseInt to int independent of the cmake configuration. This avoids long running test cases
+// but is problematic for this test.
+#undef ALPAKA_CI
 #include <alpaka/alpaka.hpp>
 #include <alpaka/test/acc/TestAccs.hpp>
 
@@ -248,3 +252,28 @@ TEMPLATE_LIST_TEST_CASE("kernel specialization with tags", "[acc][tag]", TestAcc
 
     REQUIRE(alpaka::getPtrNative(memHost)[0] == expected_result);
 }
+
+TEMPLATE_LIST_TEST_CASE("test AccIsEnabled", "[acc][tag]", AccToTagMap)
+{
+    using TestAcc = std::tuple_element_t<0, TestType>;
+    using TestTag = std::tuple_element_t<1, TestType>;
+
+
+    // if the Acc is not enabled, the type is int
+    if constexpr(!std::is_same_v<TestAcc, int>)
+    {
+        STATIC_REQUIRE(alpaka::AccIsEnabled<TestTag>::value);
+    }
+    else
+    {
+        STATIC_REQUIRE_FALSE(alpaka::AccIsEnabled<TestTag>::value);
+    }
+}
+
+
+TEST_CASE("test EnabledAccTags", "[acc][tag]")
+{
+    using AllAccs = alpaka::test::EnabledAccs<alpaka::DimInt<1>, int>;
+    STATIC_REQUIRE(std::tuple_size<AllAccs>::value == std::tuple_size<alpaka::EnabledAccTags>::value);
+}
+