OpenMP: 'allocate' directive - fixes for 'alignof' and [[omp::decl]]

Fixed a check to permit [[omp::decl(allocate,...)]] parsing in C.

Additionaly, we discussed that 'allocate align' should not affect
'alignof' to avoid issues like with:

  int a;
  _Alignas(_Alignof(a)) int b;
  #pragma omp allocate(a) align(128)
  _Alignas(_Alignof(a)) int c;

Thus, the alignment is no longer set in the C and Fortran front ends,
but for static variables now in varpool_node::finalize_decl.
(For stack variables, the alignment is handled in gimplify_bind_expr.)

NOTE: 'omp allocate' is not yet supported in C++.

gcc/c/ChangeLog:

	* c-parser.cc (c_parser_omp_allocate): Only check scope if
	not in_omp_decl_attribute. Remove setting the alignment.

gcc/ChangeLog:

	* cgraphunit.cc (varpool_node::finalize_decl): Set alignment
	based on OpenMP's 'omp allocate' attribute/directive.

gcc/fortran/ChangeLog:

	* trans-decl.cc (gfc_finish_var_decl): Remove setting the alignment.

libgomp/ChangeLog:

	* libgomp.texi (Memory allocation): Mention (non-)effect of 'align'
	on _Alignof.
	* testsuite/libgomp.c/allocate-7.c: New test.

gcc/testsuite/ChangeLog:

	* c-c++-common/gomp/allocate-18.c: Check that alignof is unaffected
	by 'omp allocate'.
	* c-c++-common/gomp/allocate-19.c: Likewise.

1 files changed, 1 insertions, 4 deletions

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 0acba05..a7719ac 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -22158,7 +22158,7 @@ c_parser_omp_allocate (c_parser *parser)
 		    "%<allocate%> directive", var);
 	  continue;
 	}
-      if (!c_check_in_current_scope (var))
+      if (!parser->in_omp_decl_attribute && !c_check_in_current_scope (var))
 	{
 	  error_at (OMP_CLAUSE_LOCATION (nl),
 		    "%<allocate%> directive must be in the same scope as %qD",
@@ -22199,9 +22199,6 @@ c_parser_omp_allocate (c_parser *parser)
 	    = {EXPR_LOC_OR_LOC (allocator, OMP_CLAUSE_LOCATION (nl)), var};
 	  walk_tree (&allocator, c_check_omp_allocate_allocator_r, &data, NULL);
 	}
-      if (alignment)
-	SET_DECL_ALIGN (var, BITS_PER_UNIT * MAX (tree_to_uhwi (alignment),
-						  DECL_ALIGN_UNIT (var)));
       DECL_ATTRIBUTES (var) = tree_cons (get_identifier ("omp allocate"),
 					 build_tree_list (allocator, alignment),
 					 DECL_ATTRIBUTES (var));