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* [Patch] libgomp: Fix reverse-offload for GOMP_MAP_TO_PSET
@ 2023-02-06 11:52 Tobias Burnus
  2023-02-07 22:51 ` Thomas Schwinge
  0 siblings, 1 reply; 4+ messages in thread
From: Tobias Burnus @ 2023-02-06 11:52 UTC (permalink / raw)
  To: gcc-patches, Jakub Jelinek

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Seems as if I missed a GOMP_MAP_TO_PSET issue before. As nvptx is
XFAILed before, I only found it when testing on AMDGCN.

For an array-descriptor 'ai' variable, omplower has:
   map(tofrom:MEM <integer(kind=4)[0:]> [(integer(kind=4)[0:] *)D.4346] [len: D.4345])
   map(to:ai [pointer set, len: 64])
   map(alloc:ai.data [pointer assign, bias: 0])

The latter reaches GCC with the same address as 'ai' – i.e. the
one of the array descriptor. This then needs to be dereferenced
to get the address of the actual pointer.
The patch assumes (and asserts) that 'ai.data' is part of the 'ai'
such that I can use the host address of 'ai' to access the data.
If that's not guaranteed, we have to find another way (e.g. another
lookup). But so far it seems to hold and I have not seen a bias
other than 0.

With that patch, libgomp.fortran/reverse-offload-5.f90 now works
with AMDGCN.

OK? Any comments to the attached patch?

Tobias
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[-- Attachment #2: rev-fix-2.diff --]
[-- Type: text/x-patch, Size: 2384 bytes --]

libgomp: Fix reverse-offload for GOMP_MAP_TO_PSET

libgomp/
	* target.c (gomp_target_rev): Dereference ptr
	to get device address.
	* libgomp.fortran/reverse-offload-5.f90: Add test
	for unallocated allocatable.

 libgomp/target.c                                        | 7 ++++++-
 libgomp/testsuite/libgomp.fortran/reverse-offload-5.f90 | 6 ++++--
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/libgomp/target.c b/libgomp/target.c
index c1682caea13..5cdd845291a 100644
--- a/libgomp/target.c
+++ b/libgomp/target.c
@@ -3579,8 +3579,13 @@ gomp_target_rev (uint64_t fn_ptr, uint64_t mapnum, uint64_t devaddrs_ptr,
 		      }
 		    int k;
 		    n2 = NULL;
-		    cdata[i].present = true;
+		    /* Dereference devaddrs[j] to get the device addr.  */
+		    assert (devaddrs[j]-sizes[j] == cdata[i].devaddr);
+		    devaddrs[j] = *(uint64_t *) (devaddrs[i] + sizes[j]);
+		    cdata[j].present = true;
 		    cdata[j].devaddr = devaddrs[j];
+		    if (devaddrs[j] == 0)
+		      continue;
 		    k = gomp_map_cdata_lookup (cdata, devaddrs, kinds, sizes, j,
 					       devaddrs[j],
 					       devaddrs[j] + sizeof (void*),
diff --git a/libgomp/testsuite/libgomp.fortran/reverse-offload-5.f90 b/libgomp/testsuite/libgomp.fortran/reverse-offload-5.f90
index ef7eb7bdd52..16810eb47de 100644
--- a/libgomp/testsuite/libgomp.fortran/reverse-offload-5.f90
+++ b/libgomp/testsuite/libgomp.fortran/reverse-offload-5.f90
@@ -24,7 +24,7 @@ s2 = 55
 
 !$omp target map(to: A, A2, s1, s2)
 block
-  integer, allocatable :: ai(:), ai2(:), si1, si2
+  integer, allocatable :: ai(:), ai2(:), ai3(:), si1, si2, si3
 
   a = a * 2
   a2 = a2 * 3
@@ -38,7 +38,7 @@ block
 
   !$omp target device (ancestor:1)  &
   !$omp&       map(to: A, s1, ai, si1) map(always, to: a2, s2)  &
-  !$omp&       map(tofrom: ai2, si2)
+  !$omp&       map(tofrom: ai2, si2, ai3, si3)
     if (shared_mem) then
       if (any (a  /= 2 * [1,2,3,4])) stop 1
       if (s1 /= 4 * 532) stop 2
@@ -52,6 +52,7 @@ block
     if (any (ai2 /= [8,4,7,1])) stop 8
     if (si1 /= 64) stop 9
     if (si2 /= 765) stop 10
+    if (allocated (ai3) .or. allocated(si3)) stop 26
 
     a = a*3
     a2 = a2*7
@@ -80,6 +81,7 @@ block
   endif
   if (any (ai2 /= 21 * [8,4,7,1])) stop 24
   if (si2 /= 31 * 765) stop 25
+  if (allocated (ai3) .or. allocated(si3)) stop 27
 
   deallocate (ai, ai2, si1, si2)
 end block

^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2023-02-06 11:52 [Patch] libgomp: Fix reverse-offload for GOMP_MAP_TO_PSET Tobias Burnus
2023-02-07 22:51 ` Thomas Schwinge
2023-02-09  9:23   ` Tobias Burnus
2023-02-15 10:17     ` Jakub Jelinek

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