openmp: allocate clause vs. *reduction array sections [PR97670]

openmp: allocate clause vs. *reduction array sections [PR97670]

This patch finds the base expression of reduction array sections and uses it
in checks whether allocate clause lists only variables that have been privatized.
Also fixes a pasto that caused an ICE.

2020-11-04  Jakub Jelinek  <jakub@redhat.com>

	PR c++/97670
gcc/c-family/
	* c-omp.c (c_omp_split_clauses): Look through array reductions to find
	underlying decl to clear in the allocate_head bitmap.
gcc/c/
	* c-typeck.c (c_finish_omp_clauses): Look through array reductions to
	find underlying decl to clear in the aligned_head bitmap.
gcc/cp/
	* semantics.c (finish_omp_clauses): Look through array reductions to
	find underlying decl to clear in the aligned_head bitmap.  Use
	DECL_UID (t) instead of DECL_UID (OMP_CLAUSE_DECL (c)) when clearing
	in the bitmap.  Only diagnose errors about allocate vars not being
	privatized on the same construct on allocate clause if it has
	a DECL_P OMP_CLAUSE_DECL.
gcc/testsuite/
	* c-c++-common/gomp/allocate-4.c: New test.
	* g++.dg/gomp/allocate-2.C: New test.
	* g++.dg/gomp/allocate-3.C: New test.