[PING][PATCH] Remove incorrect warning for kernels copy clause

[Tom de Vries]

On 24/03/16 17:59, Tom de Vries wrote:
> Hi,
>
> This patch fixes an incorrect warning for the oacc copy clause.
>
> Consider this test-case:
> ...
> void
> foo (void)
> {
>    int i;
>
> #pragma acc kernels
>    {
>      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 kernels region.
>
> The warning occurs because there's an implicit copy(i) clause on the
> kernels region, and that copy generates a read of i before the region,
> and a write to i in region.
>
> The patch silences the warning by marking the variable in the copy
> 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?
>

Ping.

Thanks,
- Tom

> 0001-Remove-incorrect-warning-for-kernels-copy-clause.patch
>
>
> Remove incorrect warning for kernels copy clause
>
> 2016-03-24  Tom de Vries  <tom@codesourcery.com>
>
> 	* omp-low.c (lower_omp_target): Set TREE_NO_WARNING for oacc copy
> 	clause.
>
> 	* c-c++-common/goacc/uninit-copy-clause.c: New test.
> 	* gfortran.dg/goacc/uninit-copy-clause.f95: New test.
>
> ---
>   gcc/omp-low.c                                      |  6 +++-
>   .../c-c++-common/goacc/uninit-copy-clause.c        | 38 ++++++++++++++++++++++
>   .../gfortran.dg/goacc/uninit-copy-clause.f95       | 29 +++++++++++++++++
>   3 files changed, 72 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/omp-low.c b/gcc/omp-low.c
> index 3fd6eb3..d107961 100644
> --- a/gcc/omp-low.c
> +++ b/gcc/omp-low.c
> @@ -16083,7 +16083,11 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
>   			|| map_kind == GOMP_MAP_POINTER
>   			|| map_kind == GOMP_MAP_TO_PSET
>   			|| map_kind == GOMP_MAP_FORCE_DEVICEPTR)
> -		      gimplify_assign (avar, var, &ilist);
> +		      {
> +			if (is_gimple_omp_oacc (ctx->stmt))
> +			  TREE_NO_WARNING (var) = 1;
> +			gimplify_assign (avar, var, &ilist);
> +		      }
>   		    avar = build_fold_addr_expr (avar);
>   		    gimplify_assign (x, avar, &ilist);
>   		    if ((GOMP_MAP_COPY_FROM_P (map_kind)
> diff --git a/gcc/testsuite/c-c++-common/goacc/uninit-copy-clause.c b/gcc/testsuite/c-c++-common/goacc/uninit-copy-clause.c
> new file mode 100644
> index 0000000..b3cc445
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/goacc/uninit-copy-clause.c
> @@ -0,0 +1,38 @@
> +/* { dg-do compile } */
> +/* { dg-additional-options "-Wuninitialized" } */
> +
> +void
> +foo (void)
> +{
> +  int i;
> +
> +#pragma acc kernels
> +  {
> +    i = 1;
> +  }
> +
> +}
> +
> +void
> +foo2 (void)
> +{
> +  int i;
> +
> +#pragma acc kernels copy (i)
> +  {
> +    i = 1;
> +  }
> +
> +}
> +
> +void
> +foo3 (void)
> +{
> +  int i;
> +
> +#pragma acc kernels copyin(i)
> +  {
> +    i = 1;
> +  }
> +
> +}
> diff --git a/gcc/testsuite/gfortran.dg/goacc/uninit-copy-clause.f95 b/gcc/testsuite/gfortran.dg/goacc/uninit-copy-clause.f95
> new file mode 100644
> index 0000000..b2aae1d
> --- /dev/null
> +++ b/gcc/testsuite/gfortran.dg/goacc/uninit-copy-clause.f95
> @@ -0,0 +1,29 @@
> +! { dg-do compile }
> +! { dg-additional-options "-Wuninitialized" }
> +
> +subroutine foo
> +  integer :: i
> +
> +  !$acc kernels
> +  i = 1
> +  !$acc end kernels
> +
> +end subroutine foo
> +
> +subroutine foo2
> +  integer :: i
> +
> +  !$acc kernels copy (i)
> +  i = 1
> +  !$acc end kernels
> +
> +end subroutine foo2
> +
> +subroutine foo3
> +  integer :: i
> +
> +  !$acc kernels copyin (i)
> +  i = 1
> +  !$acc end kernels
> +
> +end subroutine foo3
>