Ensure pointer is copied to target when USM is active (llvm#450)

Author: ronlieb

offload/libomptarget/omptarget.cpp

@@ -488,7 +488,16 @@ int targetDataBegin(ident_t *Loc, DeviceTy &Device, int32_t ArgNum,
       ArgsBase[I] = TgtPtrBase;
     }
 
-    if (ArgTypes[I] & OMP_TGT_MAPTYPE_PTR_AND_OBJ && !IsHostPtr)
+    // The || part of the if condition covers flang dope vectors that
+    // have different host and target addresses when USM is enabled. The
+    // pointer to the array is IsHostPtr but the dope vector is not.
+    // This happens  with dope vectors in Fortran modules.
+    // The pointer has to be copied into the
+    // target dope vector.
+    // Perhaps OMP_TGT_MAPTYPE_DESCRIPTOR would help here, not sure.
+    if ((ArgTypes[I] & OMP_TGT_MAPTYPE_PTR_AND_OBJ) &&
+        (!IsHostPtr || (PointerTpr.getEntry() != nullptr &&
+                        PointerHstPtrBegin != PointerTgtPtrBegin)))
       if (prepareAndSubmitData(Device, HstPtrBegin, HstPtrBase, TgtPtrBegin,
                                PointerTpr, PointerHstPtrBegin,
                                PointerTgtPtrBegin,