On Tue, 11 May 2021 19:28:04 +0800
Chung-Lin Tang <clt...@codesourcery.com> wrote:
> This patch largely implements three pieces of functionality:
>
> (1) Per discussion and clarification on the omp-lang mailing list,
> standards conforming behavior for mapping array sections should *NOT*
> also map the base-pointer, i.e for this code:
>
> struct S { int *ptr; ... };
> struct S s;
> #pragma omp target enter data map(to: s.ptr[:100])
>
> Currently we generate after gimplify:
> #pragma omp target enter data map(struct:s [len: 1]) map(alloc:s.ptr
> [len: 8]) \ map(to:*_1 [len: 400]) map(attach:s.ptr [bias: 0])
>
> which is deemed incorrect. After this patch, the gimplify results are
> now adjusted to: #pragma omp target enter data map(to:*_1 [len: 400])
> map(attach:s.ptr [bias: 0]) (the attach operation is still generated,
> and if s.ptr is already mapped prior, attachment will happen)
Oh, that's not going to play nicely (eventually?) with the patch series
I just posted... we probably need to clarify what the intention is for
OpenACC, but IIUC "user expectation" (i.e. existing code) expects the
base-pointer mapping to happen.
Julian
