This patch rewrites reference-type variables appearing in OpenACC
"private" clauses in a similar way to how such variables are handled in
reduction clauses. Otherwise, the mechanism used to privatize reference
variables is currently ill-suited to the worker-partitioning mechanism
used for AMD GCN, and each worker ends up accessing worker 0's copy of
those reference variables via broadcast pointers. Rewriting reference
variables to non-reference-type scalars sidesteps that problem.
This is intended as a somewhat temporary solution: it works for the
newly-included tests, but is not very elegant.
Tested with offloading to AMD GCN. I will apply to the
openacc-gcc-9-branch shortly.
Cheers,
Julian
ChangeLog
gcc/
* gimplify.c (localize_reductions): Rewrite references for
OMP_CLAUSE_PRIVATE also.
libgomp/
* testsuite/libgomp.oacc-fortran/privatized-ref-1.f95: New test.
* testsuite/libgomp.oacc-c++/privatized-ref-2.C: New test.
* testsuite/libgomp.oacc-c++/privatized-ref-3.C: New test.
---
gcc/ChangeLog.openacc | 5 ++
gcc/gimplify.c | 15 ++++
libgomp/ChangeLog.openacc | 6 ++
.../libgomp.oacc-c++/privatized-ref-2.C | 64 +++++++++++++++++
.../libgomp.oacc-c++/privatized-ref-3.C | 64 +++++++++++++++++
.../libgomp.oacc-fortran/privatized-ref-1.f95 | 71 +++++++++++++++++++
6 files changed, 225 insertions(+)
create mode 100644 libgomp/testsuite/libgomp.oacc-c++/privatized-ref-2.C
create mode 100644 libgomp/testsuite/libgomp.oacc-c++/privatized-ref-3.C
create mode 100644 libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-1.f95
diff --git a/gcc/ChangeLog.openacc b/gcc/ChangeLog.openacc
index fe584959153..523b6eb1d74 100644
--- a/gcc/ChangeLog.openacc
+++ b/gcc/ChangeLog.openacc
@@ -1,3 +1,8 @@
+2019-09-20 Julian Brown <jul...@codesourcery.com>
+
+ * gimplify.c (localize_reductions): Rewrite references for
+ OMP_CLAUSE_PRIVATE also.
+
2019-09-17 Tobias Burnus <tob...@codesourcery.com>
* config/gcn/gcn.c (gcn_expand_scalar_to_vector_address,
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index d16611d3617..d95ad5d4baa 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -10879,6 +10879,21 @@ localize_reductions (tree clauses, tree body)
OMP_CLAUSE_REDUCTION_PRIVATE_DECL (c) = new_var;
}
+ else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_PRIVATE)
+ {
+ var = OMP_CLAUSE_DECL (c);
+
+ if (!lang_hooks.decls.omp_privatize_by_reference (var))
+ continue;
+
+ type = TREE_TYPE (TREE_TYPE (var));
+ new_var = create_tmp_var (type, IDENTIFIER_POINTER (DECL_NAME (var)));
+
+ pr.ref_var = var;
+ pr.local_var = new_var;
+
+ walk_tree (&body, localize_reductions_r, &pr, NULL);
+ }
}
diff --git a/libgomp/ChangeLog.openacc b/libgomp/ChangeLog.openacc
index 7813760e642..d9d1c353e31 100644
--- a/libgomp/ChangeLog.openacc
+++ b/libgomp/ChangeLog.openacc
@@ -1,3 +1,9 @@
+2019-09-20 Julian Brown <jul...@codesourcery.com>
+
+ * testsuite/libgomp.oacc-fortran/privatized-ref-1.f95: New test.
+ * testsuite/libgomp.oacc-c++/privatized-ref-2.C: New test.
+ * testsuite/libgomp.oacc-c++/privatized-ref-3.C: New test.
+
2019-09-19 Julian Brown <jul...@codesourcery.com>
* plugin/plugin-nvptx.c (GOMP_OFFLOAD_openacc_async_host2dev):
diff --git a/libgomp/testsuite/libgomp.oacc-c++/privatized-ref-2.C
b/libgomp/testsuite/libgomp.oacc-c++/privatized-ref-2.C
new file mode 100644
index 00000000000..3884f163132
--- /dev/null
+++ b/libgomp/testsuite/libgomp.oacc-c++/privatized-ref-2.C
@@ -0,0 +1,64 @@
+/* { dg-do run } */
+
+#include <stdlib.h>
+
+void workers (void)
+{
+ double res[65536];
+ int i;
+
+#pragma acc parallel copyout(res) num_gangs(64) num_workers(64)
+ {
+ int i, j;
+#pragma acc loop gang
+ for (i = 0; i < 256; i++)
+ {
+#pragma acc loop worker
+ for (j = 0; j < 256; j++)
+ {
+ int tmpvar;
+ int &tmpref = tmpvar;
+ tmpref = (i * 256 + j) * 99;
+ res[i * 256 + j] = tmpref;
+ }
+ }
+ }
+
+ for (i = 0; i < 65536; i++)
+ if (res[i] != i * 99)
+ abort ();
+}
+
+void vectors (void)
+{
+ double res[65536];
+ int i;
+
+#pragma acc parallel copyout(res) num_gangs(64) num_workers(64)
+ {
+ int i, j;
+#pragma acc loop gang worker
+ for (i = 0; i < 256; i++)
+ {
+#pragma acc loop vector
+ for (j = 0; j < 256; j++)
+ {
+ int tmpvar;
+ int &tmpref = tmpvar;
+ tmpref = (i * 256 + j) * 101;
+ res[i * 256 + j] = tmpref;
+ }
+ }
+ }
+
+ for (i = 0; i < 65536; i++)
+ if (res[i] != i * 101)
+ abort ();
+}
+
+int main (int argc, char *argv[])
+{
+ workers ();
+ vectors ();
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.oacc-c++/privatized-ref-3.C
b/libgomp/testsuite/libgomp.oacc-c++/privatized-ref-3.C
new file mode 100644
index 00000000000..c1a10cba31b
--- /dev/null
+++ b/libgomp/testsuite/libgomp.oacc-c++/privatized-ref-3.C
@@ -0,0 +1,64 @@
+/* { dg-do run } */
+
+#include <stdlib.h>
+
+void workers (void)
+{
+ double res[65536];
+ int i;
+
+#pragma acc parallel copyout(res) num_gangs(64) num_workers(64)
+ {
+ int i, j;
+ int tmpvar;
+ int &tmpref = tmpvar;
+#pragma acc loop gang
+ for (i = 0; i < 256; i++)
+ {
+#pragma acc loop worker private(tmpref)
+ for (j = 0; j < 256; j++)
+ {
+ tmpref = (i * 256 + j) * 99;
+ res[i * 256 + j] = tmpref;
+ }
+ }
+ }
+
+ for (i = 0; i < 65536; i++)
+ if (res[i] != i * 99)
+ abort ();
+}
+
+void vectors (void)
+{
+ double res[65536];
+ int i;
+
+#pragma acc parallel copyout(res) num_gangs(64) num_workers(64)
+ {
+ int i, j;
+ int tmpvar;
+ int &tmpref = tmpvar;
+#pragma acc loop gang worker
+ for (i = 0; i < 256; i++)
+ {
+#pragma acc loop vector private(tmpref)
+ for (j = 0; j < 256; j++)
+ {
+ tmpref = (i * 256 + j) * 101;
+ res[i * 256 + j] = tmpref;
+ }
+ }
+ }
+
+ for (i = 0; i < 65536; i++)
+ if (res[i] != i * 101)
+ abort ();
+}
+
+int main (int argc, char *argv[])
+{
+ workers ();
+ vectors ();
+ return 0;
+}
diff --git a/libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-1.f95
b/libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-1.f95
new file mode 100644
index 00000000000..f16f69c1d1b
--- /dev/null
+++ b/libgomp/testsuite/libgomp.oacc-fortran/privatized-ref-1.f95
@@ -0,0 +1,71 @@
+! { dg-do run }
+
+program main
+ implicit none
+ integer :: myint
+ integer :: i
+ real :: res(65536), tmp
+
+ res(:) = 0.0
+
+ myint = 5
+ call workers(myint, res)
+
+ do i=1,65536
+ tmp = i * 99
+ if (res(i) .ne. tmp) stop 1
+ end do
+
+ res(:) = 0.0
+
+ myint = 7
+ call vectors(myint, res)
+
+ do i=1,65536
+ tmp = i * 101
+ if (res(i) .ne. tmp) stop 2
+ end do
+
+contains
+
+ subroutine workers(t1, res)
+ implicit none
+ integer :: t1
+ integer :: i, j
+ real, intent(out) :: res(:)
+
+ !$acc parallel copyout(res) num_gangs(64) num_workers(64)
+
+ !$acc loop gang
+ do i=0,255
+ !$acc loop worker private(t1)
+ do j=1,256
+ t1 = (i * 256 + j) * 99
+ res(i * 256 + j) = t1
+ end do
+ end do
+
+ !$acc end parallel
+ end subroutine workers
+
+ subroutine vectors(t1, res)
+ implicit none
+ integer :: t1
+ integer :: i, j
+ real, intent(out) :: res(:)
+
+ !$acc parallel copyout(res) num_gangs(64) num_workers(64)
+
+ !$acc loop gang worker
+ do i=0,255
+ !$acc loop vector private(t1)
+ do j=1,256
+ t1 = (i * 256 + j) * 101
+ res(i * 256 + j) = t1
+ end do
+ end do
+
+ !$acc end parallel
+ end subroutine vectors
+
+end program main
--
2.22.0
