libgomp: plugin-gcn - support 'unified_address'

Effectively, for GCN (as for nvptx) there is a common address space between
host and device, whether being accessible or not. Thus, this commit
permits to use 'omp requires unified_address' with GCN devices.
(nvptx accepts this requirement since r13-3460-g131d18e928a3ea.)

libgomp/

	* plugin/plugin-gcn.c (GOMP_OFFLOAD_get_num_devices): Regard
	unified_address requirement as supported.
	* libgomp.texi (OpenMP 5.0, AMD Radeon, nvptx): Remove
	'unified_address' from the not-supported requirements.

2 files changed, 7 insertions, 6 deletions

diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index 76c56a7..a3d370a 100644
--- a/libgomp/libgomp.texi
+++ b/libgomp/libgomp.texi
@@ -192,8 +192,7 @@ The OpenMP 4.5 specification is fully supported.
       env variable @tab Y @tab
 @item Nested-parallel changes to @emph{max-active-levels-var} ICV @tab Y @tab
 @item @code{requires} directive @tab P
-      @tab complete but no non-host devices provides @code{unified_address} or
-      @code{unified_shared_memory}
+      @tab complete but no non-host devices provides @code{unified_shared_memory}
 @item @code{teams} construct outside an enclosing target region @tab Y @tab
 @item Non-rectangular loop nests @tab P @tab Full support for C/C++, partial for Fortran
 @item @code{!=} as relational-op in canonical loop form for C/C++ @tab Y @tab
@@ -4460,7 +4459,7 @@ The implementation remark:
       @code{device(ancestor:1)}) are processed serially per @code{target} region
       such that the next reverse offload region is only executed after the previous
       one returned.
-@item OpenMP code that has a requires directive with @code{unified_address} or
+@item OpenMP code that has a @code{requires} directive with
       @code{unified_shared_memory} will remove any GCN device from the list of
       available devices (``host fallback'').
 @item The available stack size can be changed using the @code{GCN_STACK_SIZE}
@@ -4522,8 +4521,8 @@ The implementation remark:
       Per device, reverse offload regions are processed serially such that
       the next reverse offload region is only executed after the previous
       one returned.
-@item OpenMP code that has a requires directive with @code{unified_address}
-      or @code{unified_shared_memory} will remove any nvptx device from the
+@item OpenMP code that has a @code{requires} directive with
+      @code{unified_shared_memory} will remove any nvptx device from the
       list of available devices (``host fallback'').
 @end itemize
 
diff --git a/libgomp/plugin/plugin-gcn.c b/libgomp/plugin/plugin-gcn.c
index 2181bf0..ef22d48 100644
--- a/libgomp/plugin/plugin-gcn.c
+++ b/libgomp/plugin/plugin-gcn.c
@@ -3231,7 +3231,9 @@ GOMP_OFFLOAD_get_num_devices (unsigned int omp_requires_mask)
   /* Return -1 if no omp_requires_mask cannot be fulfilled but
      devices were present.  */
   if (hsa_context.agent_count > 0
-      && (omp_requires_mask & ~GOMP_REQUIRES_REVERSE_OFFLOAD) != 0)
+      && ((omp_requires_mask
+	   & ~(GOMP_REQUIRES_UNIFIED_ADDRESS
+	       | GOMP_REQUIRES_REVERSE_OFFLOAD)) != 0))
     return -1;
   return hsa_context.agent_count;
 }