[SYCL] Update doxygen comments for memcpy/copy (#8026)

There is no requirement for any pointer to be strictly inside a USM
allocation, host allocation is also allowed.

Fixes #4159

Author: aelovikov-intel

sycl/include/sycl/handler.hpp

@@ -2386,8 +2386,9 @@ class __SYCL_EXPORT handler {
   __SYCL2020_DEPRECATED("use 'ext_oneapi_barrier' instead")
   void barrier(const std::vector<event> &WaitList);
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on this handler's
+  /// device.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.
@@ -2397,8 +2398,9 @@ class __SYCL_EXPORT handler {
   /// \param Count is a number of bytes to copy.
   void memcpy(void *Dest, const void *Src, size_t Count);
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on this handler's
+  /// device.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.

sycl/include/sycl/queue.hpp

@@ -554,8 +554,9 @@ class __SYCL_EXPORT queue : public detail::OwnerLessBase<queue> {
   event memset(void *Ptr, int Value, size_t Count,
                const std::vector<event> &DepEvents);
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on the device
+  /// associated with this queue.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.
@@ -566,8 +567,9 @@ class __SYCL_EXPORT queue : public detail::OwnerLessBase<queue> {
   /// \return an event representing copy operation.
   event memcpy(void *Dest, const void *Src, size_t Count);
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on the device
+  /// associated with this queue.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.
@@ -579,8 +581,9 @@ class __SYCL_EXPORT queue : public detail::OwnerLessBase<queue> {
   /// \return an event representing copy operation.
   event memcpy(void *Dest, const void *Src, size_t Count, event DepEvent);
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on the device
+  /// associated with this queue.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.
@@ -594,8 +597,9 @@ class __SYCL_EXPORT queue : public detail::OwnerLessBase<queue> {
   event memcpy(void *Dest, const void *Src, size_t Count,
                const std::vector<event> &DepEvents);
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on the device
+  /// associated with this queue.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.
@@ -612,8 +616,9 @@ class __SYCL_EXPORT queue : public detail::OwnerLessBase<queue> {
     return this->memcpy(Dest, Src, Count * sizeof(T));
   }
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on the device
+  /// associated with this queue.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.
@@ -632,8 +637,9 @@ class __SYCL_EXPORT queue : public detail::OwnerLessBase<queue> {
     return this->memcpy(Dest, Src, Count * sizeof(T), DepEvent);
   }
 
-  /// Copies data from one memory region to another, both pointed by
-  /// USM pointers.
+  /// Copies data from one memory region to another, each is either a host
+  /// pointer or a pointer within USM allocation accessible on the device
+  /// associated with this queue.
   /// No operations is done if \param Count is zero. An exception is thrown
   /// if either \param Dest or \param Src is nullptr. The behavior is undefined
   /// if any of the pointer parameters is invalid.