[PATCH, OpenACC] Enable 0-length array data mappings for implicit data clauses

[Chung-Lin Tang <chunglin_tang at mentor dot com>]

Hi Thomas, this patch allows the gimplifier to create 0-length array mappings
for certain pointer and reference typed variables. Without this, array usage
of certain pointer variables do not work as usually intended, this is the
original description by Cesar when applied to og7:
https://gcc.gnu.org/ml/gcc-patches/2017-10/msg00673.html

Note that this patch requires this to cleanly apply (still awaiting approval):
https://gcc.gnu.org/ml/gcc-patches/2018-06/msg01911.html

Thomas, since this only touches OpenACC, I suppose you have the powers to approve.

Thanks,
Chung-Lin

2018-11-06  Cesar Philippidis  <cesar@codesourcery.com>

	gcc/
	* gimplify.c (oacc_default_clause): Create implicit 0-length
	array data clauses for pointers and reference types.

	libgomp/
	* testsuite/libgomp.oacc-c-c++-common/fp-dyn-arrays.c: New test.

Attachment: openacc-0-length.patch
Description: Text document