On Thu, Sep 10, 2020 at 11:17:34AM +0200, Tobias Burnus wrote:
> Hi Jakub, hello all,
>
> when looking at target.c, I stumbled over that code:
> size_t mapnum → unsigned
> if (mapnum == 0)
> ...
> return;
>
> if (mapnum > 0 || ....)
> ...
But it is not mapnum > 0 here but mapnum > 1
So, for mapnum == 1 and e.g. target enter data it doesn't need to create the
chunks stuff, for a single mapping there is nothing to merge together.
> diff --git a/libgomp/target.c b/libgomp/target.c
> index 3e292eb8c62..440aad6b048 100644
> --- a/libgomp/target.c
> +++ b/libgomp/target.c
> @@ -676,28 +676,23 @@ gomp_map_vars_internal (struct gomp_device_descr
> *devicep,
> if (mapnum == 0)
> {
> tgt->tgt_start = 0;
> tgt->tgt_end = 0;
> return tgt;
> }
>
> tgt_align = sizeof (void *);
> tgt_size = 0;
> - cbuf.chunks = NULL;
> - cbuf.chunk_cnt = -1;
> + cbuf.chunk_cnt = 0;
> cbuf.use_cnt = 0;
> - cbuf.buf = NULL;
> - if (mapnum > 1 || pragma_kind == GOMP_MAP_VARS_TARGET)
> - {
> - size_t chunks_size = (mapnum + 1) * sizeof (struct
> gomp_coalesce_chunk);
> - cbuf.chunks = (struct gomp_coalesce_chunk *) gomp_alloca (chunks_size);
> - cbuf.chunk_cnt = 0;
> - }
> + size_t chunks_size = (mapnum + 1) * sizeof (struct gomp_coalesce_chunk);
> + cbuf.chunks = (struct gomp_coalesce_chunk *) gomp_alloca (chunks_size);
> +
> if (pragma_kind == GOMP_MAP_VARS_TARGET)
> {
> size_t align = 4 * sizeof (void *);
> tgt_align = align;
> tgt_size = mapnum * sizeof (void *);
> cbuf.chunk_cnt = 1;
> cbuf.use_cnt = 1 + (mapnum > 1);
> cbuf.chunks[0].start = 0;
> cbuf.chunks[0].end = tgt_size;
Jakub
