Revert "[NFC][SYCL] Switch to std::enable_if (#7628)"

libdevice/cmake/modules/SYCLLibdevice.cmake

@@ -32,18 +32,6 @@ set(compile_opts
   -sycl-std=2020
   )
 
-if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-  # If we use non-system GCC, need to pass its location when using
-  # freshly built clang. The system one might be very old.
-  get_filename_component(gcc_bin_dir ${CMAKE_CXX_COMPILER} DIRECTORY)
-  get_filename_component(gcc_install_dir ${gcc_bin_dir} DIRECTORY)
-  # /bin/g++ doesn't need any fixup. We also need to check that ccache is
-  # not being used.
-  if (NOT gcc_install_dir STREQUAL "/" AND NOT gcc_bin_dir MATCHES "ccache")
-    list(APPEND compile_opts "--gcc-toolchain=${gcc_install_dir}")
-  endif()
-endif()
-
 if ("NVPTX" IN_LIST LLVM_TARGETS_TO_BUILD)
   string(APPEND sycl_targets_opt ",nvptx64-nvidia-cuda")
   list(APPEND compile_opts

sycl/include/CL/__spirv/spirv_ops.hpp

@@ -338,23 +338,23 @@ extern SYCL_EXTERNAL TempRetT __spirv_ImageSampleExplicitLod(SampledType,
 // of atomic min/max based on the type
 #define __SPIRV_ATOMIC_MINMAX(AS, Op)                                          \
   template <typename T>                                                        \
-  typename std::enable_if_t<                                                   \
+  typename sycl::detail::enable_if_t<                                          \
       std::is_integral<T>::value && std::is_signed<T>::value, T>               \
       __spirv_Atomic##Op(AS T *Ptr, __spv::Scope::Flag Memory,                 \
                          __spv::MemorySemanticsMask::Flag Semantics,           \
                          T Value) {                                            \
     return __spirv_AtomicS##Op(Ptr, Memory, Semantics, Value);                 \
   }                                                                            \
   template <typename T>                                                        \
-  typename std::enable_if_t<                                                   \
+  typename sycl::detail::enable_if_t<                                          \
       std::is_integral<T>::value && !std::is_signed<T>::value, T>              \
       __spirv_Atomic##Op(AS T *Ptr, __spv::Scope::Flag Memory,                 \
                          __spv::MemorySemanticsMask::Flag Semantics,           \
                          T Value) {                                            \
     return __spirv_AtomicU##Op(Ptr, Memory, Semantics, Value);                 \
   }                                                                            \
   template <typename T>                                                        \
-  typename std::enable_if_t<std::is_floating_point<T>::value, T>               \
+  typename sycl::detail::enable_if_t<std::is_floating_point<T>::value, T>      \
       __spirv_Atomic##Op(AS T *Ptr, __spv::Scope::Flag Memory,                 \
                          __spv::MemorySemanticsMask::Flag Semantics,           \
                          T Value) {                                            \

sycl/include/sycl/atomic.hpp

@@ -210,7 +210,7 @@ class __SYCL2020_DEPRECATED(
 #ifdef __ENABLE_USM_ADDR_SPACE__
   // Create atomic in global_space with one from ext_intel_global_device_space
   template <access::address_space _Space = addressSpace,
-            typename = typename std::enable_if_t<
+            typename = typename detail::enable_if_t<
                 _Space == addressSpace &&
                 addressSpace == access::address_space::global_space>>
   atomic(const atomic<T, access::address_space::ext_intel_global_device_space>
@@ -219,7 +219,7 @@ class __SYCL2020_DEPRECATED(
   }
 
   template <access::address_space _Space = addressSpace,
-            typename = typename std::enable_if_t<
+            typename = typename detail::enable_if_t<
                 _Space == addressSpace &&
                 addressSpace == access::address_space::global_space>>
   atomic(
@@ -235,13 +235,13 @@ class __SYCL2020_DEPRECATED(
 
 #ifdef __SYCL_DEVICE_ONLY__
   template <typename T2 = T>
-  std::enable_if_t<!std::is_same<cl_float, T2>::value, T>
+  detail::enable_if_t<!std::is_same<cl_float, T2>::value, T>
   load(memory_order Order = memory_order::relaxed) const {
     return __spirv_AtomicLoad(Ptr, SpirvScope,
                               detail::getSPIRVMemorySemanticsMask(Order));
   }
   template <typename T2 = T>
-  std::enable_if_t<std::is_same<cl_float, T2>::value, T>
+  detail::enable_if_t<std::is_same<cl_float, T2>::value, T>
   load(memory_order Order = memory_order::relaxed) const {
     auto *TmpPtr = reinterpret_cast<typename multi_ptr<
         cl_int, addressSpace, access::decorated::yes>::pointer>(Ptr);

sycl/include/sycl/atomic_ref.hpp

@@ -89,7 +89,7 @@ inline constexpr memory_order getLoadOrder(memory_order order) {
 template <typename T, typename = void> struct bit_equal;
 
 template <typename T>
-struct bit_equal<T, typename std::enable_if_t<std::is_integral<T>::value>> {
+struct bit_equal<T, typename detail::enable_if_t<std::is_integral<T>::value>> {
   bool operator()(const T &lhs, const T &rhs) { return lhs == rhs; }
 };
 
@@ -266,7 +266,7 @@ class atomic_ref_impl
 template <typename T, memory_order DefaultOrder, memory_scope DefaultScope,
           access::address_space AddressSpace>
 class atomic_ref_impl<T, DefaultOrder, DefaultScope, AddressSpace,
-                      typename std::enable_if_t<std::is_integral<T>::value>>
+                      typename detail::enable_if_t<std::is_integral<T>::value>>
     : public atomic_ref_base<T, DefaultOrder, DefaultScope, AddressSpace> {
 
 public:
@@ -414,7 +414,7 @@ template <typename T, memory_order DefaultOrder, memory_scope DefaultScope,
           access::address_space AddressSpace>
 class atomic_ref_impl<
     T, DefaultOrder, DefaultScope, AddressSpace,
-    typename std::enable_if_t<std::is_floating_point<T>::value>>
+    typename detail::enable_if_t<std::is_floating_point<T>::value>>
     : public atomic_ref_base<T, DefaultOrder, DefaultScope, AddressSpace> {
 
 public:

sycl/include/sycl/backend/opencl.hpp

@@ -33,32 +33,32 @@ __SYCL_EXPORT bool has_extension(const sycl::device &SyclDevice,
                                  const std::string &Extension);
 
 // Construction of SYCL platform.
-template <typename T, typename std::enable_if_t<
+template <typename T, typename detail::enable_if_t<
                           std::is_same<T, platform>::value> * = nullptr>
 __SYCL_DEPRECATED("Use SYCL 2020 sycl::make_platform free function")
 T make(typename detail::interop<backend::opencl, T>::type Interop) {
   return make_platform(detail::pi::cast<pi_native_handle>(Interop));
 }
 
 // Construction of SYCL device.
-template <typename T,
-          typename std::enable_if_t<std::is_same<T, device>::value> * = nullptr>
+template <typename T, typename detail::enable_if_t<
+                          std::is_same<T, device>::value> * = nullptr>
 __SYCL_DEPRECATED("Use SYCL 2020 sycl::make_device free function")
 T make(typename detail::interop<backend::opencl, T>::type Interop) {
   return make_device(detail::pi::cast<pi_native_handle>(Interop));
 }
 
 // Construction of SYCL context.
-template <typename T, typename std::enable_if_t<std::is_same<T, context>::value>
-                          * = nullptr>
+template <typename T, typename detail::enable_if_t<
+                          std::is_same<T, context>::value> * = nullptr>
 __SYCL_DEPRECATED("Use SYCL 2020 sycl::make_context free function")
 T make(typename detail::interop<backend::opencl, T>::type Interop) {
   return make_context(detail::pi::cast<pi_native_handle>(Interop));
 }
 
 // Construction of SYCL queue.
-template <typename T,
-          typename std::enable_if_t<std::is_same<T, queue>::value> * = nullptr>
+template <typename T, typename detail::enable_if_t<
+                          std::is_same<T, queue>::value> * = nullptr>
 __SYCL_DEPRECATED("Use SYCL 2020 sycl::make_queue free function")
 T make(const context &Context,
        typename detail::interop<backend::opencl, T>::type Interop) {

sycl/include/sycl/buffer.hpp

@@ -140,8 +140,8 @@ class __SYCL_EXPORT buffer_plain {
 /// \ingroup sycl_api
 template <typename T, int dimensions = 1,
           typename AllocatorT = buffer_allocator<std::remove_const_t<T>>,
-          typename __Enabled =
-              typename std::enable_if_t<(dimensions > 0) && (dimensions <= 3)>>
+          typename __Enabled = typename detail::enable_if_t<(dimensions > 0) &&
+                                                            (dimensions <= 3)>>
 class buffer : public detail::buffer_plain,
                public detail::OwnerLessBase<buffer<T, dimensions, AllocatorT>> {
   // TODO check is_device_copyable<T>::value after converting sycl::vec into a
@@ -155,21 +155,21 @@ class buffer : public detail::buffer_plain,
   using const_reference = const value_type &;
   using allocator_type = AllocatorT;
   template <int dims>
-  using EnableIfOneDimension = typename std::enable_if_t<1 == dims>;
+  using EnableIfOneDimension = typename detail::enable_if_t<1 == dims>;
   // using same requirement for contiguous container as std::span
   template <class Container>
   using EnableIfContiguous =
-      detail::void_t<std::enable_if_t<std::is_convertible<
+      detail::void_t<detail::enable_if_t<std::is_convertible<
                          detail::remove_pointer_t<
                              decltype(std::declval<Container>().data())> (*)[],
                          const T (*)[]>::value>,
                      decltype(std::declval<Container>().size())>;
   template <class It>
-  using EnableIfItInputIterator = std::enable_if_t<
+  using EnableIfItInputIterator = detail::enable_if_t<
       std::is_convertible<typename std::iterator_traits<It>::iterator_category,
                           std::input_iterator_tag>::value>;
   template <typename ItA, typename ItB>
-  using EnableIfSameNonConstIterators = typename std::enable_if_t<
+  using EnableIfSameNonConstIterators = typename detail::enable_if_t<
       std::is_same<ItA, ItB>::value && !std::is_const<ItA>::value, ItA>;
 
   std::array<size_t, 3> rangeToArray(range<3> &r) { return {r[0], r[1], r[2]}; }
@@ -575,7 +575,7 @@ class buffer : public detail::buffer_plain,
   }
 
   template <template <typename WeakT> class WeakPtrT, typename WeakT>
-  std::enable_if_t<
+  detail::enable_if_t<
       std::is_convertible<WeakPtrT<WeakT>, std::weak_ptr<WeakT>>::value>
   set_final_data_internal(WeakPtrT<WeakT> FinalData) {
     std::weak_ptr<WeakT> TempFinalData(FinalData);