On Tue, Apr 05, 2016 at 06:53:47PM -0700, Cesar Philippidis wrote:
> --- a/gcc/omp-low.c
> +++ b/gcc/omp-low.c
> @@ -309,6 +309,25 @@ is_oacc_kernels (omp_context *ctx)
> == GF_OMP_TARGET_KIND_OACC_KERNELS));
> }
>
> +/* Return true if CTX corresponds to an oacc parallel region and if
> + VAR is used in a reduction. */
> +
> +static bool
> +is_oacc_parallel_reduction (tree var, omp_context *ctx)
> +{
> + if (!is_oacc_parallel (ctx))
> + return false;
> +
> + tree clauses = gimple_omp_target_clauses (ctx->stmt);
> +
> + for (tree c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
> + if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_REDUCTION
> + && OMP_CLAUSE_DECL (c) == var)
> + return true;
> +
> + return false;
> +}
> +
> /* If DECL is the artificial dummy VAR_DECL created for non-static
> data member privatization, return the underlying "this" parameter,
> otherwise return NULL. */
> @@ -2122,7 +2141,8 @@ scan_sharing_clauses (tree clauses, omp_context *ctx,
> else
> install_var_field (decl, true, 3, ctx,
> base_pointers_restrict);
> - if (is_gimple_omp_offloaded (ctx->stmt))
> + if (is_gimple_omp_offloaded (ctx->stmt)
> + && !is_oacc_parallel_reduction (decl, ctx))
> install_var_local (decl, ctx);
> }
> }
The above is O(n^2) in number of clauses on the construct.
Perhaps better define some OMP_CLAUSE_MAP_IN_REDUCTION macro (e.g.
TREE_PRIVATE bit is unused on OMP_CLAUSE_MAP right now), make sure to set it
e.g. during gimplification where you can see all GOVD_* flags for a
particular decl), and then use this flag here?
Jakub
