[clang] [llvm] [WIP][OpenMP] Adds omp_target_is_accessible routine (PR #138294)

[Michael Klemm via llvm-commits]

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@@ -195,6 +196,48 @@ EXTERN int omp_target_is_present(const void *Ptr, int DeviceNum) {
   return Rc;
 }
 
+/// Check whether a pointer is accessible from a device.
+/// the functionality is available in OpenMP 5.1 and later
+/// OpenMP 5.1
+/// omp_target_is_accessible checks whether a host pointer is accessible from a
+/// device OpenMP 6.0 removes restriction on pointer, allowing any pointer
+/// interpreted as a pointer in the address space of the given device.
+EXTERN int omp_target_is_accessible(const void *Ptr, size_t Size,
+                                    int DeviceNum) {
+  TIMESCOPE();
+  OMPT_IF_BUILT(ReturnAddressSetterRAII RA(__builtin_return_address(0)));
+  DP("Call to omp_target_is_accessible for device %d, address " DPxMOD
+     ", size %zu\n",
+     DeviceNum, DPxPTR(Ptr), Size);
+
+  if (!Ptr) {
+    DP("Call to omp_target_is_accessible with NULL ptr returning false\n");
+    return false;
+  }
+
+  if (DeviceNum == omp_get_initial_device()) {
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mjklemm wrote:

Please do the correct check in this routine.  I agree with your position of creating a new PR for fixing up the other routines.  Can you please record that as an issue?

https://github.com/llvm/llvm-project/pull/138294