Index: libomptarget/include/omptarget.h
===================================================================
--- libomptarget/include/omptarget.h
+++ libomptarget/include/omptarget.h
@@ -47,6 +47,8 @@
   OMP_TGT_MAPTYPE_LITERAL         = 0x100,
   // mapping is implicit
   OMP_TGT_MAPTYPE_IMPLICIT        = 0x200,
+  // copy data to device
+  OMP_TGT_MAPTYPE_CLOSE           = 0x400,
   // member of struct, member given by [16 MSBs] - 1
   OMP_TGT_MAPTYPE_MEMBER_OF       = 0xffff000000000000
 };
Index: libomptarget/src/device.h
===================================================================
--- libomptarget/src/device.h
+++ libomptarget/src/device.h
@@ -137,11 +137,13 @@
   long getMapEntryRefCnt(void *HstPtrBegin);
   LookupResult lookupMapping(void *HstPtrBegin, int64_t Size);
   void *getOrAllocTgtPtr(void *HstPtrBegin, void *HstPtrBase, int64_t Size,
-      bool &IsNew, bool &IsHostPtr, bool IsImplicit, bool UpdateRefCount = true);
+      bool &IsNew, bool &IsHostPtr, bool IsImplicit, bool UpdateRefCount = true,
+      bool IsCloseModifier = false);
   void *getTgtPtrBegin(void *HstPtrBegin, int64_t Size);
   void *getTgtPtrBegin(void *HstPtrBegin, int64_t Size, bool &IsLast,
       bool UpdateRefCount, bool &IsHostPtr);
-  int deallocTgtPtr(void *TgtPtrBegin, int64_t Size, bool ForceDelete);
+  int deallocTgtPtr(void *TgtPtrBegin, int64_t Size, bool ForceDelete,
+                    bool IsCloseModifier = false);
   int associatePtr(void *HstPtrBegin, void *TgtPtrBegin, int64_t Size);
   int disassociatePtr(void *HstPtrBegin);
 
Index: libomptarget/src/device.cpp
===================================================================
--- libomptarget/src/device.cpp
+++ libomptarget/src/device.cpp
@@ -158,7 +158,7 @@
 // to do an illegal mapping.
 void *DeviceTy::getOrAllocTgtPtr(void *HstPtrBegin, void *HstPtrBase,
     int64_t Size, bool &IsNew, bool &IsHostPtr, bool IsImplicit,
-    bool UpdateRefCount) {
+    bool UpdateRefCount, bool IsCloseModifier) {
   void *rc = NULL;
   IsHostPtr = false;
   DataMapMtx.lock();
@@ -170,7 +170,7 @@
   // maps are respected.
   // TODO: In addition to the mapping rules above, when the close map
   // modifier is implemented, foce the mapping of the variable to the device.
-  if (RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY &&
+  if (RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY && !IsCloseModifier &&
       (IsImplicit || !lr.Flags.IsContained || Size)) {
     DP("Return HstPtrBegin " DPxMOD " Size=%ld RefCount=%s\n",
        DPxPTR((uintptr_t)HstPtrBegin), Size, (UpdateRefCount ? " updated" : ""));
@@ -200,7 +200,10 @@
     } else if (Size) {
       // If it is not contained and Size > 0 we should create a new entry for it.
       IsNew = true;
-      uintptr_t tp = (uintptr_t)RTL->data_alloc(RTLDeviceID, Size, HstPtrBegin);
+      uintptr_t tp = 0;
+      if (!(RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY) ||
+          (RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY && IsCloseModifier))
+        tp = (uintptr_t)RTL->data_alloc(RTLDeviceID, Size, HstPtrBegin);
       DP("Creating new map entry: HstBase=" DPxMOD ", HstBegin=" DPxMOD ", "
           "HstEnd=" DPxMOD ", TgtBegin=" DPxMOD "\n", DPxPTR(HstPtrBase),
           DPxPTR(HstPtrBegin), DPxPTR((uintptr_t)HstPtrBegin + Size), DPxPTR(tp));
@@ -274,8 +277,9 @@
   return NULL;
 }
 
-int DeviceTy::deallocTgtPtr(void *HstPtrBegin, int64_t Size, bool ForceDelete) {
-  if (RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)
+int DeviceTy::deallocTgtPtr(void *HstPtrBegin, int64_t Size, bool ForceDelete,
+                            bool IsCloseModifier) {
+  if (RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY && !IsCloseModifier)
     return OFFLOAD_SUCCESS;
   // Check if the pointer is contained in any sub-nodes.
   int rc;
Index: libomptarget/src/omptarget.cpp
===================================================================
--- libomptarget/src/omptarget.cpp
+++ libomptarget/src/omptarget.cpp
@@ -244,6 +244,9 @@
     bool IsNew, Pointer_IsNew;
     bool IsHostPtr = false;
     bool IsImplicit = arg_types[i] & OMP_TGT_MAPTYPE_IMPLICIT;
+    // Force the creation of a device side copy of the data when:
+    // a close map modifier was associated with a map that contained a to.
+    bool IsCloseModifier = arg_types[i] & OMP_TGT_MAPTYPE_CLOSE;
     // UpdateRef is based on MEMBER_OF instead of TARGET_PARAM because if we
     // have reached this point via __tgt_target_data_begin and not __tgt_target
     // then no argument is marked as TARGET_PARAM ("omp target data map" is not
@@ -254,7 +257,8 @@
       DP("Has a pointer entry: \n");
       // base is address of pointer.
       Pointer_TgtPtrBegin = Device.getOrAllocTgtPtr(HstPtrBase, HstPtrBase,
-          sizeof(void *), Pointer_IsNew, IsHostPtr, IsImplicit, UpdateRef);
+          sizeof(void *), Pointer_IsNew, IsHostPtr, IsImplicit, UpdateRef,
+          IsCloseModifier);
       if (!Pointer_TgtPtrBegin) {
         DP("Call to getOrAllocTgtPtr returned null pointer (device failure or "
             "illegal mapping).\n");
@@ -270,7 +274,7 @@
     }
 
     void *TgtPtrBegin = Device.getOrAllocTgtPtr(HstPtrBegin, HstPtrBase,
-        data_size, IsNew, IsHostPtr, IsImplicit, UpdateRef);
+        data_size, IsNew, IsHostPtr, IsImplicit, UpdateRef, IsCloseModifier);
     if (!TgtPtrBegin && data_size) {
       // If data_size==0, then the argument could be a zero-length pointer to
       // NULL, so getOrAlloc() returning NULL is not an error.
@@ -290,8 +294,11 @@
 
     if (arg_types[i] & OMP_TGT_MAPTYPE_TO) {
       bool copy = false;
-      if (!(Device.RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)) {
-        if (IsNew || (arg_types[i] & OMP_TGT_MAPTYPE_ALWAYS)) {
+      bool Close = arg_types[i] & OMP_TGT_MAPTYPE_CLOSE;
+      if (!(Device.RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY) ||
+          (Device.RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY &&
+           Close)) {
+        if (IsNew || (arg_types[i] & OMP_TGT_MAPTYPE_ALWAYS) || Close) {
           copy = true;
         } else if (arg_types[i] & OMP_TGT_MAPTYPE_MEMBER_OF) {
           // Copy data only if the "parent" struct has RefCount==1.
@@ -370,6 +377,7 @@
     bool UpdateRef = !(arg_types[i] & OMP_TGT_MAPTYPE_MEMBER_OF) ||
         (arg_types[i] & OMP_TGT_MAPTYPE_PTR_AND_OBJ);
     bool ForceDelete = arg_types[i] & OMP_TGT_MAPTYPE_DELETE;
+    bool IsCloseModifier = arg_types[i] & OMP_TGT_MAPTYPE_CLOSE;
 
     // If PTR_AND_OBJ, HstPtrBegin is address of pointee
     void *TgtPtrBegin = Device.getTgtPtrBegin(HstPtrBegin, data_size, IsLast,
@@ -389,8 +397,11 @@
       // Move data back to the host
       if (arg_types[i] & OMP_TGT_MAPTYPE_FROM) {
         bool Always = arg_types[i] & OMP_TGT_MAPTYPE_ALWAYS;
+        bool Close = arg_types[i] & OMP_TGT_MAPTYPE_CLOSE;
         bool CopyMember = false;
-        if (!(Device.RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY)) {
+        if (!(Device.RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY) ||
+            (Device.RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY &&
+             Close)) {
           if ((arg_types[i] & OMP_TGT_MAPTYPE_MEMBER_OF) &&
               !(arg_types[i] & OMP_TGT_MAPTYPE_PTR_AND_OBJ)) {
             // Copy data only if the "parent" struct has RefCount==1.
@@ -403,9 +414,9 @@
           }
         }
 
-        if ((DelEntry || Always || CopyMember) &&
+        if ((DelEntry || Always || CopyMember || Close) &&
             !(Device.RTLRequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY &&
-              TgtPtrBegin == HstPtrBegin)) {
+              TgtPtrBegin == HstPtrBegin && !Close)) {
           DP("Moving %" PRId64 " bytes (tgt:" DPxMOD ") -> (hst:" DPxMOD ")\n",
               data_size, DPxPTR(TgtPtrBegin), DPxPTR(HstPtrBegin));
           int rt = Device.data_retrieve(HstPtrBegin, TgtPtrBegin, data_size);
@@ -455,7 +466,8 @@
 
       // Deallocate map
       if (DelEntry) {
-        int rt = Device.deallocTgtPtr(HstPtrBegin, data_size, ForceDelete);
+        int rt = Device.deallocTgtPtr(HstPtrBegin, data_size, ForceDelete,
+                                      IsCloseModifier);
         if (rt != OFFLOAD_SUCCESS) {
           DP("Deallocating data from device failed.\n");
           return OFFLOAD_FAIL;
Index: libomptarget/test/unified_shared_memory/close_modifier.c
===================================================================
--- /dev/null
+++ libomptarget/test/unified_shared_memory/close_modifier.c
@@ -0,0 +1,131 @@
+// RUN: %libomptarget-compile-run-and-check-aarch64-unknown-linux-gnu
+// RUN: %libomptarget-compile-run-and-check-powerpc64-ibm-linux-gnu
+// RUN: %libomptarget-compile-run-and-check-powerpc64le-ibm-linux-gnu
+// RUN: %libomptarget-compile-run-and-check-x86_64-pc-linux-gnu
+
+#include <stdio.h>
+#include <omp.h>
+
+#pragma omp requires unified_shared_memory
+
+#define N 1024
+
+int main(int argc, char *argv[]) {
+  int fails;
+  long long host_alloc, device_alloc;
+  long long host_data, device_data;
+  double *alloc = (double *)malloc(N*sizeof(double));
+  double data[N];
+
+  for(int i=0; i<N; ++i){
+    alloc[i] = 10.0;
+    data[i] = 1.0;
+  }
+
+  host_data = (long long) &data[0];
+  host_alloc = (long long) &alloc[0];
+
+  //
+  // Test that updates on the device are not visible to host
+  // when only a TO mapping is used.
+  //
+  #pragma omp target map(tofrom: device_data, device_alloc) \
+                     map(close,to: alloc[:N], data[:N])
+  {
+    device_data = (long long) &data[0];
+    device_alloc = (long long) &alloc[0];
+
+    for(int i=0; i<N; i++) {
+      alloc[i] += 1.0;
+      data[i] += 1.0;
+    }
+  }
+
+  // CHECK: Address of alloc on device different from host address.
+  if (device_alloc != host_alloc)
+    printf("Address of alloc on device different from host address.\n");
+
+  // CHECK: Address of data on device different from host address.
+  if (device_data != host_data)
+    printf("Address of data on device different from host address.\n");
+
+  // On the host, check that the arrays have been updated.
+  // CHECK: Alloc host values not updated: Succeeded
+  fails = 0;
+  for(int i=0; i<N; i++) {
+    if (alloc[i] != 10.0)
+      fails++;
+  }
+  printf("Alloc host values not updated: %s\n",
+      (fails == 0) ? "Succeeded" : "Failed");
+
+  // CHECK: Data host values not updated: Succeeded
+  fails = 0;
+  for(int i=0; i<N; i++) {
+    if (data[i] != 1.0)
+      fails++;
+  }
+  printf("Data host values not updated: %s\n",
+      (fails == 0) ? "Succeeded" : "Failed");
+
+  //
+  // Test that updates on the device are visible on host
+  // when a from is used.
+  //
+
+  for(int i=0; i<N; i++) {
+    alloc[i] += 1.0;
+    data[i] += 1.0;
+  }
+
+  #pragma omp target map(close,tofrom: alloc[:N], data[:N])
+  {
+    // CHECK: Alloc device values are correct: Succeeded
+    fails = 0;
+    for(int i=0; i<N; i++) {
+      if (alloc[i] != 11.0)
+        fails++;
+    }
+    printf("Alloc device values are correct: %s\n",
+        (fails == 0) ? "Succeeded" : "Failed");
+    // CHECK: Data device values are correct: Succeeded
+    fails = 0;
+    for(int i=0; i<N; i++) {
+      if (data[i] != 2.0)
+        fails++;
+    }
+    printf("Data device values are correct: %s\n",
+        (fails == 0) ? "Succeeded" : "Failed");
+
+    // Update values on the device
+    for(int i=0; i<N; i++) {
+      alloc[i] += 1.0;
+      data[i] += 1.0;
+    }
+  }
+
+  // CHECK: Alloc host values updated: Succeeded
+  fails = 0;
+  for(int i=0; i<N; i++) {
+    if (alloc[i] != 12.0)
+      fails++;
+  }
+  printf("Alloc host values updated: %s\n",
+      (fails == 0) ? "Succeeded" : "Failed");
+
+  // CHECK: Data host values updated: Succeeded
+  fails = 0;
+  for(int i=0; i<N; i++) {
+    if (data[i] != 3.0)
+      fails++;
+  }
+  printf("Data host values updated: %s\n",
+      (fails == 0) ? "Succeeded" : "Failed");
+
+  free(alloc);
+
+  // CHECK: Done!
+  printf("Done!\n");
+
+  return 0;
+}