[PATCH, v2, libgomp, OpenMP 5.0] Implement omp_get_device_num

[Chung-Lin Tang <cltang@codesourcery.com>]

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On 2021/7/23 6:39 PM, Jakub Jelinek wrote:
> On Fri, Jul 23, 2021 at 06:21:41PM +0800, Chung-Lin Tang wrote:
>> --- a/libgomp/icv-device.c
>> +++ b/libgomp/icv-device.c
>> @@ -61,8 +61,17 @@ omp_is_initial_device (void)
>>     return 1;
>>   }
>>   
>> +int
>> +omp_get_device_num (void)
>> +{
>> +  /* By specification, this is equivalent to omp_get_initial_device
>> +     on the host.  */
>> +  return omp_get_initial_device ();
>> +}
>> +
> 
> I think this won't work properly with the intel micoffload, where the host
> libgomp is used in the offloaded code.
> For omp_is_initial_device, the plugin solves it by:
> liboffloadmic/plugin/offload_target_main.cpp
> overriding it:
> /* Override the corresponding functions from libgomp.  */
> extern "C" int
> omp_is_initial_device (void) __GOMP_NOTHROW
> {
>    return 0;
> }
>     
> extern "C" int32_t
> omp_is_initial_device_ (void)
> {
>    return omp_is_initial_device ();
> }
> but guess it will need slightly more work because we need to copy the value
> to the offloading device too.
> It can be done incrementally though.

I guess this part of intelmic functionality will just have to wait later.
There seem to be other parts of liboffloadmic that seems to need re-work,
e.g. omp_get_num_devices() return mic_engines_total, where it should actually
return the number of all devices (not just intelmic). omp_get_initial_device()
returning -1 (which I don't quite understand), etc.

Really suggest to have intelmic support be re-worked as an offload plugin inside
libgomp, rather than floating outside by itself.

>> --- a/libgomp/libgomp-plugin.h
>> +++ b/libgomp/libgomp-plugin.h
>> @@ -102,6 +102,12 @@ struct addr_pair
>>     uintptr_t end;
>>   };
>>   
>> +/* This symbol is to name a target side variable that holds the designated
>> +   'device number' of the target device. The symbol needs to be available to
>> +   libgomp code and the  offload plugin (which in the latter case must be
>> +   stringified).  */
>> +#define GOMP_DEVICE_NUM_VAR __gomp_device_num
> 
> For a single var it is acceptable (though, please avoid the double space
> before offload plugin in the comment), but once we have more than one
> variable, I think we should simply have a struct which will contain all the
> parameters that need to be copied from the host to the offloading device at
> image load time (and have eventually another struct that holds parameters
> that we'll need to copy to the device on each kernel launch, I bet some ICVs
> will be one category, other ICVs another one).

Actually, if you look at the 5.[01] specifications, omp_get_device_num() is not
defined in terms of an ICV. Maybe it conceptually ought to be, but the current
description of "the device number of the device on which the calling thread is
executing" is not one if the defined ICVs.

It looks like there will eventually be some kind of ICV block handled in a similar
way, but I think that the modifications will be straightforward then. For now,
I think it's okay for GOMP_DEVICE_NUM_VAR to just be a normal global variable.

>> diff --git a/libgomp/libgomp.map b/libgomp/libgomp.map
>> index 8ea27b5565f..ffcb98ae99e 100644
>> --- a/libgomp/libgomp.map
>> +++ b/libgomp/libgomp.map
>> @@ -197,6 +197,8 @@ OMP_5.0.1 {
>>   	omp_get_supported_active_levels_;
>>   	omp_fulfill_event;
>>   	omp_fulfill_event_;
>> +	omp_get_device_num;
>> +	omp_get_device_num_;
>>   } OMP_5.0;
> 
> This is wrong.  We've already released GCC 11.1 with the OMP_5.0.1
> symbol version, so we must not add any further symbols into that symbol
> version.  OpenMP 5.0 routines added in GCC 12 should be OMP_5.0.2 symbol
> version.

I've adjusted this into 5.0.2, in between 5.0.1 and the new 5.1 added by the recent
omp_display_env[_] routines. omp_get_device_num is a OpenMP 5.0 introduced
API function, so I think this is the correct handling (instead of stashing into 5.1).

There is a new function check_effective_target_offload_target_intelmic() in
testsuite/lib/libgomp.exp, used to test for non-intelmic offloading situations.

Re-tested with no regressions, seeking approval for trunk.

Thanks,
Chung-Lin

2021-08-02  Chung-Lin Tang  <cltang@codesourcery.com>

libgomp/ChangeLog

	* icv-device.c (omp_get_device_num): New API function, host side.
	* fortran.c (omp_get_device_num_): New interface function.
	* libgomp-plugin.h (GOMP_DEVICE_NUM_VAR): Define macro symbol.
	* libgomp.map (OMP_5.0.2): New version space with omp_get_device_num,
	omp_get_device_num_.
	* libgomp.texi (omp_get_device_num): Add documentation for new API
	function.
	* omp.h.in (omp_get_device_num): Add declaration.
	* omp_lib.f90.in (omp_get_device_num): Likewise.
	* omp_lib.h.in (omp_get_device_num): Likewise.
	* target.c (gomp_load_image_to_device): If additional entry for device
	number exists at end of returned entries from 'load_image_func' hook,
	copy the assigned device number over to the device variable.

	* config/gcn/icv-device.c (GOMP_DEVICE_NUM_VAR): Define static global.
	(omp_get_device_num): New API function, device side.
	* config/plugin/plugin-gcn.c ("symcat.h"): Add include.
	(GOMP_OFFLOAD_load_image): Add addresses of device GOMP_DEVICE_NUM_VAR
	at end of returned 'target_table' entries.

	* config/nvptx/icv-device.c (GOMP_DEVICE_NUM_VAR): Define static global.
	(omp_get_device_num): New API function, device side.
	* config/plugin/plugin-nvptx.c ("symcat.h"): Add include.
	(GOMP_OFFLOAD_load_image): Add addresses of device GOMP_DEVICE_NUM_VAR
	at end of returned 'target_table' entries.

	* testsuite/lib/libgomp.exp
	(check_effective_target_offload_target_intelmic): New function for
	testing for intelmic offloading.
	* testsuite/libgomp.c-c++-common/target-45.c: New test.
	* testsuite/libgomp.fortran/target10.f90: New test.

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diff --git a/libgomp/config/gcn/icv-device.c b/libgomp/config/gcn/icv-device.c
index 72d4f7cff74..8f72028a6c8 100644
--- a/libgomp/config/gcn/icv-device.c
+++ b/libgomp/config/gcn/icv-device.c
@@ -70,6 +70,16 @@ omp_is_initial_device (void)
   return 0;
 }
 
+/* This is set to the device number of current GPU during device initialization,
+   when the offload image containing this libgomp portion is loaded.  */
+static int GOMP_DEVICE_NUM_VAR;
+
+int
+omp_get_device_num (void)
+{
+  return GOMP_DEVICE_NUM_VAR;
+}
+
 ialias (omp_set_default_device)
 ialias (omp_get_default_device)
 ialias (omp_get_initial_device)
diff --git a/libgomp/config/nvptx/icv-device.c b/libgomp/config/nvptx/icv-device.c
index 3b96890f338..e586da1d3a8 100644
--- a/libgomp/config/nvptx/icv-device.c
+++ b/libgomp/config/nvptx/icv-device.c
@@ -58,8 +58,19 @@ omp_is_initial_device (void)
   return 0;
 }
 
+/* This is set to the device number of current GPU during device initialization,
+   when the offload image containing this libgomp portion is loaded.  */
+static int GOMP_DEVICE_NUM_VAR;
+
+int
+omp_get_device_num (void)
+{
+  return GOMP_DEVICE_NUM_VAR;
+}
+
 ialias (omp_set_default_device)
 ialias (omp_get_default_device)
 ialias (omp_get_initial_device)
 ialias (omp_get_num_devices)
 ialias (omp_is_initial_device)
+ialias (omp_get_device_num)
diff --git a/libgomp/fortran.c b/libgomp/fortran.c
index e042702ac91..5cff8840eab 100644
--- a/libgomp/fortran.c
+++ b/libgomp/fortran.c
@@ -599,6 +599,12 @@ omp_get_initial_device_ (void)
   return omp_get_initial_device ();
 }
 
+int32_t
+omp_get_device_num_ (void)
+{
+  return omp_get_device_num ();
+}
+
 int32_t
 omp_get_max_task_priority_ (void)
 {
diff --git a/libgomp/icv-device.c b/libgomp/icv-device.c
index c1bedf46647..f11bdfa85c4 100644
--- a/libgomp/icv-device.c
+++ b/libgomp/icv-device.c
@@ -61,8 +61,17 @@ omp_is_initial_device (void)
   return 1;
 }
 
+int
+omp_get_device_num (void)
+{
+  /* By specification, this is equivalent to omp_get_initial_device
+     on the host.  */
+  return omp_get_initial_device ();
+}
+
 ialias (omp_set_default_device)
 ialias (omp_get_default_device)
 ialias (omp_get_initial_device)
 ialias (omp_get_num_devices)
 ialias (omp_is_initial_device)
+ialias (omp_get_device_num)
diff --git a/libgomp/libgomp-plugin.h b/libgomp/libgomp-plugin.h
index 62645ce9954..cf24a2bee41 100644
--- a/libgomp/libgomp-plugin.h
+++ b/libgomp/libgomp-plugin.h
@@ -102,6 +102,12 @@ struct addr_pair
   uintptr_t end;
 };
 
+/* This symbol is to name a target side variable that holds the designated
+   'device number' of the target device. The symbol needs to be available to
+   libgomp code and the offload plugin (which in the latter case must be
+   stringified).  */
+#define GOMP_DEVICE_NUM_VAR __gomp_device_num
+
 /* Miscellaneous functions.  */
 extern void *GOMP_PLUGIN_malloc (size_t) __attribute__ ((malloc));
 extern void *GOMP_PLUGIN_malloc_cleared (size_t) __attribute__ ((malloc));
diff --git a/libgomp/libgomp.map b/libgomp/libgomp.map
index 69aa69562b8..cc44885cba9 100644
--- a/libgomp/libgomp.map
+++ b/libgomp/libgomp.map
@@ -199,12 +199,18 @@ OMP_5.0.1 {
 	omp_fulfill_event_;
 } OMP_5.0;
 
+OMP_5.0.2 {
+  global:
+	omp_get_device_num;
+	omp_get_device_num_;
+} OMP_5.0.1;
+
 OMP_5.1 {
   global:
 	omp_display_env;
 	omp_display_env_;
 	omp_display_env_8_;
-} OMP_5.0.1;
+} OMP_5.0.2;
 
 GOMP_1.0 {
   global:
diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index 2c1f1b5968b..fc9e708a8d2 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -165,6 +165,7 @@ linkage, and do not throw exceptions.
 * omp_get_ancestor_thread_num:: Ancestor thread ID
 * omp_get_cancellation::        Whether cancellation support is enabled
 * omp_get_default_device::      Get the default device for target regions
+* omp_get_device_num::          Get device that current thread is running on
 * omp_get_dynamic::             Dynamic teams setting
 * omp_get_initial_device::      Device number of host device
 * omp_get_level::               Number of parallel regions
@@ -385,6 +386,34 @@ For OpenMP 5.1, this must be equal to the value returned by the
 
 
 
+@node omp_get_device_num
+@section @code{omp_get_device_num} -- Return device number of current device
+@table @asis
+@item @emph{Description}:
+This function returns a device number that represents the device that the
+current thread is executing on. For OpenMP 5.0, this must be equal to the
+value returned by the @code{omp_get_initial_device} function when called
+from the host.
+
+@item @emph{C/C++}
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{int omp_get_device_num(void);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{integer function omp_get_device_num()}
+@end multitable
+
+@item @emph{See also}:
+@ref{omp_get_initial_device}
+
+@item @emph{Reference}:
+@uref{https://www.openmp.org, OpenMP specification v5.0}, Section 3.2.37.
+@end table
+
+
+
 @node omp_get_level
 @section @code{omp_get_level} -- Obtain the current nesting level
 @table @asis
diff --git a/libgomp/omp.h.in b/libgomp/omp.h.in
index c93db968d2e..da34a9d98a6 100644
--- a/libgomp/omp.h.in
+++ b/libgomp/omp.h.in
@@ -243,6 +243,7 @@ extern void omp_get_partition_place_nums (int *) __GOMP_NOTHROW;
 extern void omp_set_default_device (int) __GOMP_NOTHROW;
 extern int omp_get_default_device (void) __GOMP_NOTHROW;
 extern int omp_get_num_devices (void) __GOMP_NOTHROW;
+extern int omp_get_device_num (void) __GOMP_NOTHROW;
 extern int omp_get_num_teams (void) __GOMP_NOTHROW;
 extern int omp_get_team_num (void) __GOMP_NOTHROW;
 
diff --git a/libgomp/omp_lib.f90.in b/libgomp/omp_lib.f90.in
index 5fc6587e49e..d7e804f4fd5 100644
--- a/libgomp/omp_lib.f90.in
+++ b/libgomp/omp_lib.f90.in
@@ -550,6 +550,12 @@
           end function omp_get_initial_device
         end interface
 
+        interface
+          function omp_get_device_num ()
+            integer (4) :: omp_get_device_num
+          end function omp_get_device_num
+        end interface
+
         interface
           function omp_get_max_task_priority ()
             integer (4) :: omp_get_max_task_priority
diff --git a/libgomp/omp_lib.h.in b/libgomp/omp_lib.h.in
index 9873cea9ac1..20c32645e3c 100644
--- a/libgomp/omp_lib.h.in
+++ b/libgomp/omp_lib.h.in
@@ -244,6 +244,9 @@
       external omp_get_initial_device
       integer(4) omp_get_initial_device
 
+      external omp_get_device_num
+      integer(4) omp_get_device_num
+
       external omp_get_max_task_priority
       integer(4) omp_get_max_task_priority
 
diff --git a/libgomp/plugin/plugin-gcn.c b/libgomp/plugin/plugin-gcn.c
index 2548614a2e5..e6d8b6aae25 100644
--- a/libgomp/plugin/plugin-gcn.c
+++ b/libgomp/plugin/plugin-gcn.c
@@ -29,6 +29,7 @@
 /* {{{ Includes and defines  */
 
 #include "config.h"
+#include "symcat.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -3305,6 +3306,7 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
   struct kernel_info *kernel;
   int kernel_count = image_desc->kernel_count;
   unsigned var_count = image_desc->global_variable_count;
+  int other_count = 1;
 
   agent = get_agent_info (ord);
   if (!agent)
@@ -3321,7 +3323,8 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
 
   GCN_DEBUG ("Encountered %d kernels in an image\n", kernel_count);
   GCN_DEBUG ("Encountered %u global variables in an image\n", var_count);
-  pair = GOMP_PLUGIN_malloc ((kernel_count + var_count - 2)
+  GCN_DEBUG ("Expect %d other variables in an image\n", other_count);
+  pair = GOMP_PLUGIN_malloc ((kernel_count + var_count + other_count - 2)
 			     * sizeof (struct addr_pair));
   *target_table = pair;
   module = (struct module_info *)
@@ -3396,6 +3399,35 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
       pair++;
     }
 
+  GCN_DEBUG ("Looking for variable %s\n", STRINGX (GOMP_DEVICE_NUM_VAR));
+
+  hsa_status_t status;
+  hsa_executable_symbol_t var_symbol;
+  status = hsa_fns.hsa_executable_get_symbol_fn (agent->executable, NULL,
+						 STRINGX (GOMP_DEVICE_NUM_VAR),
+						 agent->id, 0, &var_symbol);
+  if (status == HSA_STATUS_SUCCESS)
+    {
+      uint64_t device_num_varptr;
+      uint32_t device_num_varsize;
+
+      status = hsa_fns.hsa_executable_symbol_get_info_fn
+	(var_symbol, HSA_EXECUTABLE_SYMBOL_INFO_VARIABLE_ADDRESS,
+	 &device_num_varptr);
+      if (status != HSA_STATUS_SUCCESS)
+	hsa_fatal ("Could not extract a variable from its symbol", status);
+      status = hsa_fns.hsa_executable_symbol_get_info_fn
+	(var_symbol, HSA_EXECUTABLE_SYMBOL_INFO_VARIABLE_SIZE,
+	 &device_num_varsize);
+      if (status != HSA_STATUS_SUCCESS)
+	hsa_fatal ("Could not extract a variable size from its symbol", status);
+
+      pair->start = device_num_varptr;
+      pair->end = device_num_varptr + device_num_varsize;
+    }
+  else
+    pair->start = pair->end = 0;
+
   /* Ensure that constructors are run first.  */
   struct GOMP_kernel_launch_attributes kla =
     { 3,
@@ -3418,7 +3450,7 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
   if (module->fini_array_func)
     kernel_count--;
 
-  return kernel_count + var_count;
+  return kernel_count + var_count + other_count;
 }
 
 /* Unload GCN object-code module described by struct gcn_image_desc in
diff --git a/libgomp/plugin/plugin-nvptx.c b/libgomp/plugin/plugin-nvptx.c
index 1215212d501..8b34895a88f 100644
--- a/libgomp/plugin/plugin-nvptx.c
+++ b/libgomp/plugin/plugin-nvptx.c
@@ -34,6 +34,7 @@
 #define _GNU_SOURCE
 #include "openacc.h"
 #include "config.h"
+#include "symcat.h"
 #include "libgomp-plugin.h"
 #include "oacc-plugin.h"
 #include "gomp-constants.h"
@@ -1265,7 +1266,7 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
   CUmodule module;
   const char *const *var_names;
   const struct targ_fn_launch *fn_descs;
-  unsigned int fn_entries, var_entries, i, j;
+  unsigned int fn_entries, var_entries, other_entries, i, j;
   struct targ_fn_descriptor *targ_fns;
   struct addr_pair *targ_tbl;
   const nvptx_tdata_t *img_header = (const nvptx_tdata_t *) target_data;
@@ -1295,8 +1296,11 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
   fn_entries = img_header->fn_num;
   fn_descs = img_header->fn_descs;
 
+  /* Currently, the only other entry kind is 'device number'.  */
+  other_entries = 1;
+
   targ_tbl = GOMP_PLUGIN_malloc (sizeof (struct addr_pair)
-				 * (fn_entries + var_entries));
+				 * (fn_entries + var_entries + other_entries));
   targ_fns = GOMP_PLUGIN_malloc (sizeof (struct targ_fn_descriptor)
 				 * fn_entries);
 
@@ -1345,9 +1349,22 @@ GOMP_OFFLOAD_load_image (int ord, unsigned version, const void *target_data,
       targ_tbl->end = targ_tbl->start + bytes;
     }
 
+  CUdeviceptr device_num_varptr;
+  size_t device_num_varsize;
+  CUresult r = CUDA_CALL_NOCHECK (cuModuleGetGlobal, &device_num_varptr,
+				  &device_num_varsize, module,
+				  STRINGX (GOMP_DEVICE_NUM_VAR));
+  if (r == CUDA_SUCCESS)
+    {
+      targ_tbl->start = (uintptr_t) device_num_varptr;
+      targ_tbl->end = (uintptr_t) (device_num_varptr + device_num_varsize);
+    }
+  else
+    targ_tbl->start = targ_tbl->end = 0;
+
   nvptx_set_clocktick (module, dev);
 
-  return fn_entries + var_entries;
+  return fn_entries + var_entries + other_entries;
 }
 
 /* Unload the program described by TARGET_DATA.  DEV_DATA is the
diff --git a/libgomp/target.c b/libgomp/target.c
index 453b3210e40..96f3d6ad1cf 100644
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -1974,6 +1974,9 @@ gomp_load_image_to_device (struct gomp_device_descr *devicep, unsigned version,
   int num_funcs = host_funcs_end - host_func_table;
   int num_vars  = (host_vars_end - host_var_table) / 2;
 
+  /* Others currently is only 'device_num' */
+  int num_others = 1;
+
   /* Load image to device and get target addresses for the image.  */
   struct addr_pair *target_table = NULL;
   int i, num_target_entries;
@@ -1982,7 +1985,9 @@ gomp_load_image_to_device (struct gomp_device_descr *devicep, unsigned version,
     = devicep->load_image_func (devicep->target_id, version,
 				target_data, &target_table);
 
-  if (num_target_entries != num_funcs + num_vars)
+  if (num_target_entries != num_funcs + num_vars
+      /* Others (device_num) are included as trailing entries in pair list.  */
+      && num_target_entries != num_funcs + num_vars + num_others)
     {
       gomp_mutex_unlock (&devicep->lock);
       if (is_register_lock)
@@ -2054,6 +2059,31 @@ gomp_load_image_to_device (struct gomp_device_descr *devicep, unsigned version,
       array++;
     }
 
+  /* Last entry is for the on-device 'device_num' variable. Tolerate case
+     where plugin does not return this entry.  */
+  if (num_funcs + num_vars < num_target_entries)
+    {
+      struct addr_pair *device_num_var = &target_table[num_funcs + num_vars];
+      if (device_num_var->start != 0)
+	{
+	  /* The index of the devicep within devices[] is regarded as its
+	     'device number', which is different from the per-device type
+	     devicep->target_id.  */
+	  int device_num_val = (int) (devicep - &devices[0]);
+	  if (device_num_var->end - device_num_var->start != sizeof (int))
+	    {
+	      gomp_mutex_unlock (&devicep->lock);
+	      gomp_fatal ("offload plugin managed 'device_num' not of expected "
+			  "format");
+	    }
+
+	  /* Copy device_num value to place on device memory, hereby actually
+	     designating its device number into effect.  */
+	  gomp_copy_host2dev (devicep, NULL, (void *) device_num_var->start,
+			      &device_num_val, sizeof (int), false, NULL);
+	}
+    }
+
   free (target_table);
 }
 
diff --git a/libgomp/testsuite/lib/libgomp.exp b/libgomp/testsuite/lib/libgomp.exp
index a2050151e84..ba8a73275c5 100644
--- a/libgomp/testsuite/lib/libgomp.exp
+++ b/libgomp/testsuite/lib/libgomp.exp
@@ -374,6 +374,11 @@ proc check_effective_target_offload_target_amdgcn { } {
     return [libgomp_check_effective_target_offload_target "amdgcn"]
 }
 
+# Return 1 if compiling for offload target intelmic
+proc check_effective_target_offload_target_intelmic { } {
+    return [libgomp_check_effective_target_offload_target "*-intelmic"]
+}
+
 # Return 1 if offload device is available.
 proc check_effective_target_offload_device { } {
     return [check_runtime_nocache offload_device_available_ {
diff --git a/libgomp/testsuite/libgomp.c-c++-common/target-45.c b/libgomp/testsuite/libgomp.c-c++-common/target-45.c
new file mode 100644
index 00000000000..ec0d202e51c
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/target-45.c
@@ -0,0 +1,30 @@
+/* { dg-do run { target { ! offload_target_intelmic } } } */
+
+#include <omp.h>
+#include <stdlib.h>
+
+int main (void)
+{
+
+  int host_device_num = omp_get_device_num ();
+
+  if (host_device_num != omp_get_initial_device ())
+    abort ();
+
+  int device_num;
+  int initial_device;
+
+  #pragma omp target map(from: device_num, initial_device)
+  {
+    initial_device = omp_is_initial_device ();
+    device_num = omp_get_device_num ();
+  }
+
+  if (initial_device && host_device_num != device_num)
+    abort ();
+
+  if (!initial_device && host_device_num == device_num)
+    abort ();
+
+  return 0;
+}
diff --git a/libgomp/testsuite/libgomp.fortran/target10.f90 b/libgomp/testsuite/libgomp.fortran/target10.f90
new file mode 100644
index 00000000000..a7a6422fdc4
--- /dev/null
+++ b/libgomp/testsuite/libgomp.fortran/target10.f90
@@ -0,0 +1,20 @@
+! { dg-do run { target { ! offload_target_intelmic } } }
+
+program main
+  use omp_lib
+  implicit none
+  integer :: device_num, host_device_num
+  logical :: initial_device
+
+  host_device_num = omp_get_device_num ()
+  if (host_device_num .ne. omp_get_initial_device ()) stop 1
+
+  !$omp target map(from: device_num, initial_device)
+  initial_device = omp_is_initial_device ()
+  device_num = omp_get_device_num ()
+  !$omp end target
+
+  if (initial_device .and. host_device_num .ne. device_num) stop 2
+  if (initial_device .and. host_device_num .eq. device_num) stop 3
+
+end program main