[SYCL] Reflect get_pointer updates to legacy specialized multi_ptr. (intel#10417)

* Update the legacy multi_ptr construction from local_accessors to
conform with the construction method used by other accessors.
* Implement a test for the legacy multi_ptr construction using
local_accessor.
* Use enable_if in the copy constructor and assignment operator of the
legacy/void/const-void multi_ptr specialization to prevent errors caused
by multiple overloads of 'multi_ptr'.

Author: mmoadeli

sycl/include/sycl/multi_ptr.hpp

@@ -935,7 +935,7 @@ class __SYCL2020_DEPRECATED(
                 std::is_const_v<ET> && std::is_same_v<ET, ElementType>>>
   multi_ptr(
       local_accessor<typename std::remove_const_t<ET>, dimensions> Accessor)
-      : m_Pointer(detail::cast_AS<pointer_t>(Accessor.get_pointer())) {}
+      : multi_ptr(Accessor.get_pointer()) {}
 
   // Only if Space == constant_space and element type is const
   template <
@@ -1103,6 +1103,10 @@ class __SYCL2020_DEPRECATED(
   multi_ptr(multi_ptr &&) = default;
   multi_ptr(pointer_t pointer) : m_Pointer(pointer) {}
 #ifdef __SYCL_DEVICE_ONLY__
+  template <
+      typename RelayPointerT = pointer_t,
+      typename = std::enable_if_t<std::is_same_v<RelayPointerT, pointer_t> &&
+                                  !std::is_same_v<RelayPointerT, void *>>>
   multi_ptr(void *pointer) : m_Pointer(detail::cast_AS<pointer_t>(pointer)) {
     // TODO An implementation should reject an argument if the deduced
     // address space is not compatible with Space.
@@ -1133,6 +1137,10 @@ class __SYCL2020_DEPRECATED(
     return *this;
   }
 #ifdef __SYCL_DEVICE_ONLY__
+  template <
+      typename RelayPointerT = pointer_t,
+      typename = std::enable_if_t<std::is_same_v<RelayPointerT, pointer_t> &&
+                                  !std::is_same_v<RelayPointerT, void *>>>
   multi_ptr &operator=(void *pointer) {
     // TODO An implementation should reject an argument if the deduced
     // address space is not compatible with Space.
@@ -1180,7 +1188,7 @@ class __SYCL2020_DEPRECATED(
           _Space == Space && (Space == access::address_space::generic_space ||
                               Space == access::address_space::local_space)>>
   multi_ptr(local_accessor<ElementType, dimensions> Accessor)
-      : m_Pointer(detail::cast_AS<pointer_t>(Accessor.get_pointer())) {}
+      : multi_ptr(Accessor.get_pointer()) {}
 
   // Only if Space == constant_space
   template <
@@ -1251,6 +1259,10 @@ class __SYCL2020_DEPRECATED(
   multi_ptr(multi_ptr &&) = default;
   multi_ptr(pointer_t pointer) : m_Pointer(pointer) {}
 #ifdef __SYCL_DEVICE_ONLY__
+  template <
+      typename RelayPointerT = pointer_t,
+      typename = std::enable_if_t<std::is_same_v<RelayPointerT, pointer_t> &&
+                                  !std::is_same_v<RelayPointerT, const void *>>>
   multi_ptr(const void *pointer)
       : m_Pointer(detail::cast_AS<pointer_t>(pointer)) {
     // TODO An implementation should reject an argument if the deduced
@@ -1282,6 +1294,10 @@ class __SYCL2020_DEPRECATED(
     return *this;
   }
 #ifdef __SYCL_DEVICE_ONLY__
+  template <
+      typename RelayPointerT = pointer_t,
+      typename = std::enable_if_t<std::is_same_v<RelayPointerT, pointer_t> &&
+                                  !std::is_same_v<RelayPointerT, const void *>>>
   multi_ptr &operator=(const void *pointer) {
     // TODO An implementation should reject an argument if the deduced
     // address space is not compatible with Space.
@@ -1329,7 +1345,7 @@ class __SYCL2020_DEPRECATED(
           _Space == Space && (Space == access::address_space::generic_space ||
                               Space == access::address_space::local_space)>>
   multi_ptr(local_accessor<ElementType, dimensions> Accessor)
-      : m_Pointer(detail::cast_AS<pointer_t>(Accessor.get_pointer())) {}
+      : multi_ptr(Accessor.get_pointer()) {}
 
   // Only if Space == constant_space
   template <

sycl/test-e2e/Basic/multi_ptr_legacy.hpp

@@ -76,6 +76,30 @@ template <typename T> void testMultPtr() {
                                       access::decorated::legacy>(
                 localAccessor.get_pointer());
 
+            auto local_ptr2 =
+                multi_ptr<T, access::address_space::local_space,
+                          access::decorated::legacy>(localAccessor);
+
+            auto local_ptr3 =
+                multi_ptr<void, access::address_space::local_space,
+                          access::decorated::legacy>(localAccessor);
+
+            auto local_ptr4 =
+                multi_ptr<const void, access::address_space::local_space,
+                          access::decorated::legacy>(localAccessor);
+
+            auto local_ptr5 =
+                multi_ptr<T, access::address_space::generic_space,
+                          access::decorated::legacy>(localAccessor);
+
+            auto local_ptr6 =
+                multi_ptr<void, access::address_space::generic_space,
+                          access::decorated::legacy>(localAccessor);
+
+            auto local_ptr7 =
+                multi_ptr<const void, access::address_space::generic_space,
+                          access::decorated::legacy>(localAccessor);
+
             // Construct extension pointer from accessors.
             auto dev_ptr =
                 multi_ptr<const T,