OpenACC: whole struct vs. component mappings (PR107028)

OpenACC: whole struct vs. component mappings (PR107028)

This patch fixes an ICE when both a complete struct variable and
components of that struct are mapped on the same directive for OpenACC,
using a modified version of the scheme used for OpenMP in the following
patch:

  https://gcc.gnu.org/pipermail/gcc-patches/2022-September/601558.html

A new function has been added to make sure that the mapping kinds of
the whole struct and the member access are compatible -- conservatively,
so as not to copy more to/from the device than the user expects.

This version of the patch uses a different method to detect duplicate
clauses for OpenACC in oacc_resolve_clause_dependencies, and removes
the now-redundant check in omp_accumulate_sibling_lists.  (The latter
check would no longer trigger when we map the whole struct on the same
directive because the component-mapping clauses are now deleted before
the check is executed.)

2022-09-28  Julian Brown  <julian@codesourcery.com>

gcc/
	PR middle-end/107028
	* gimplify.cc (omp_check_mapping_compatibility,
	oacc_resolve_clause_dependencies): New functions.
	(omp_accumulate_sibling_list): Remove redundant duplicate clause
	detection for OpenACC.
	(build_struct_sibling_lists): Skip deleted groups.  Don't build sibling
	list for struct variables that are fully mapped on the same directive
	for OpenACC.
	(gimplify_scan_omp_clauses): Call oacc_resolve_clause_dependencies.

gcc/testsuite/
	PR middle-end/107028
	* c-c++-common/goacc/struct-component-kind-1.c: New test.
	* g++.dg/goacc/pr107028-1.C: New test.
	* g++.dg/goacc/pr107028-2.C: New test.
	* gfortran.dg/goacc/mapping-tests-5.f90: New test.