Hi,
This patch fixes an incorrect warning for the oacc firstprivate clause.
Consider this test-case:
...
void
foo (void)
{
int i;
#pragma acc parallel
{
i = 1;
}
}
...
When compiling with -fopenacc -Wuninitialized, we get an 'is used
uninitialized' warning for variable 'i', which is confusing given that
'i' is not used, but only set in the parallel region.
The warning occurs because there's an implicit firstprivate(i) clause on
the parallel region, and that firstprivate clause generates a read of i
before the region, and a write to i in the region.
The patch silences the warning by marking the variable in the
firstprivate clause with TREE_NO_WARNING.
Build and reg-tested with goacc.exp, gomp.exp and target-libgomp.
OK for trunk if bootstrap and reg-test succeeds?
Thanks,
- Tom
Remove incorrect warning for parallel firstprivate clause
2016-03-24 Tom de Vries <t...@codesourcery.com>
* omp-low.c (lower_omp_target): Set TREE_NO_WARNING for oacc
firstprivate clause.
* c-c++-common/goacc/uninit-firstprivate-clause.c: New test.
* gfortran.dg/goacc/uninit-firstprivate-clause.f95: New test.
---
gcc/omp-low.c | 5 ++++-
.../goacc/uninit-firstprivate-clause.c | 25 ++++++++++++++++++++++
.../goacc/uninit-firstprivate-clause.f95 | 18 ++++++++++++++++
3 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index d107961..41eb3c8 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -16068,7 +16068,10 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
{
gcc_assert (is_gimple_omp_oacc (ctx->stmt));
if (!is_reference (var))
- var = build_fold_addr_expr (var);
+ {
+ TREE_NO_WARNING (var) = 1;
+ var = build_fold_addr_expr (var);
+ }
else
talign = TYPE_ALIGN_UNIT (TREE_TYPE (TREE_TYPE (ovar)));
gimplify_assign (x, var, &ilist);
diff --git a/gcc/testsuite/c-c++-common/goacc/uninit-firstprivate-clause.c b/gcc/testsuite/c-c++-common/goacc/uninit-firstprivate-clause.c
new file mode 100644
index 0000000..3d3a03e
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/uninit-firstprivate-clause.c
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-Wuninitialized" } */
+
+void
+foo (void)
+{
+ int i;
+
+#pragma acc parallel
+ {
+ i = 1;
+ }
+}
+
+
+void
+foo2 (void)
+{
+ int i;
+
+#pragma acc parallel firstprivate (i)
+ {
+ i = 1;
+ }
+}
diff --git a/gcc/testsuite/gfortran.dg/goacc/uninit-firstprivate-clause.f95 b/gcc/testsuite/gfortran.dg/goacc/uninit-firstprivate-clause.f95
new file mode 100644
index 0000000..c18765b
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/goacc/uninit-firstprivate-clause.f95
@@ -0,0 +1,18 @@
+! { dg-do compile }
+! { dg-additional-options "-Wuninitialized" }
+
+subroutine test
+ INTEGER :: i
+
+ !$acc parallel
+ i = 1
+ !$acc end parallel
+end subroutine test
+
+subroutine test2
+ INTEGER :: i
+
+ !$acc parallel firstprivate (i)
+ i = 1
+ !$acc end parallel
+end subroutine test2
