[gcc/devel/omp/gcc-13] libgomp: plugin-gcn - support 'unified_address'

[Tobias Burnus <burnus@gcc.gnu.org>]

https://gcc.gnu.org/g:04538859740c4cf7bfe9e80757f3aff34c7a2f1d

commit 04538859740c4cf7bfe9e80757f3aff34c7a2f1d
Author: Tobias Burnus <tobias@codesourcery.com>
Date:   Wed Jun 7 10:09:42 2023 +0200

    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.)
    
    OG13 note: unified_address was supported before for GCN via
      OG13 commit  3ddf3565fae  amdgcn: libgomp plugin USM implementation
    Thus, this cherry pick just uses the mainline/GCC14 syntax in the C file;
    additionally, it updates the documentation.
    
    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.
    
    (cherry picked from commit f1af7d65ff64fe7102d1490ef46ea491a533e641)

Diff:
---
 libgomp/ChangeLog.omp       | 10 ++++++++++
 libgomp/libgomp.texi        |  9 ++++-----
 libgomp/plugin/plugin-gcn.c |  7 ++++---
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 4283134a5a5..82c8690fd68 100644
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,3 +1,13 @@
+2023-06-07  Tobias Burnus  <tobias@codesourcery.com>
+
+	Backported from master:
+	2023-06-06  Tobias Burnus  <tobias@codesourcery.com>
+
+	* plugin/plugin-gcn.c (GOMP_OFFLOAD_get_num_devices): Use
+	mainline syntax for mark unified_address requirement as supported.
+	* libgomp.texi (OpenMP 5.0, AMD Radeon, nvptx): Remove
+	'unified_address' from the not-supported requirements.
+
 2023-06-01  Tobias Burnus  <tobias@codesourcery.com>
 
 	Backported from master:
diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi
index dcd2c2d3ea9..e9e74ce8ddb 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
@@ -4484,7 +4483,7 @@ 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 OpenMP @emph{pinned} memory (@code{omp_atk_pinned},
@@ -4553,8 +4552,8 @@ 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'').
 @item OpenMP @emph{pinned} memory (@code{omp_atk_pinned},
       @code{ompx_pinned_mem_alloc}, for example)
diff --git a/libgomp/plugin/plugin-gcn.c b/libgomp/plugin/plugin-gcn.c
index d6b3c615ca0..3df9fbe8d80 100644
--- a/libgomp/plugin/plugin-gcn.c
+++ b/libgomp/plugin/plugin-gcn.c
@@ -3387,10 +3387,11 @@ GOMP_OFFLOAD_get_num_devices (unsigned int omp_requires_mask)
      devices were present.
      Note: not all devices support USM, but the compiler refuses to create
      binaries for those that don't anyway.  */
-  omp_requires_mask &= ~(GOMP_REQUIRES_UNIFIED_ADDRESS
-			 | GOMP_REQUIRES_UNIFIED_SHARED_MEMORY);
+  omp_requires_mask &= ~GOMP_REQUIRES_UNIFIED_SHARED_MEMORY;
   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;
 }