The ugly part is that OpenMP 5.1 made omp_all_memory a reserved identifier
which isn't allowed to be used anywhere but in the depend clause, this is
against how everything else has been handled in OpenMP so far (where
some identifiers could have special meaning in some OpenMP clauses or
pragmas but not elsewhere).
The patch handles it by making it a conditional keyword (for -fopenmp
only) and emitting a better diagnostics when it is used in a primary
expression. Having a nicer diagnostics when e.g. trying to do
int omp_all_memory;
or
int *omp_all_memory[10];
etc. would mean changing too many spots and hooking into name lookups
to reject declaring any such symbols would be too ugly and I'm afraid
there are way too many spots where one can introduce a name
(variables, functions, namespaces, struct, enum, enumerators, template
arguments, ...).
Otherwise, the handling is quite simple, normal depend clauses lower
into addresses of variables being handed over to the library, for
omp_all_memory I'm using NULL pointers. omp_all_memory can only be
used with inout or out depend kinds and means that a task is dependent
on all previously created sibling tasks that have any dependency (of
any depend kind) and that any later created sibling tasks will be
dependent on it if they have any dependency.
2022-05-12 Jakub Jelinek <jakub@redhat.com>
gcc/
* gimplify.cc (gimplify_omp_depend): Don't build_fold_addr_expr
if null_pointer_node.
(gimplify_scan_omp_clauses): Likewise.
* tree-pretty-print.cc (dump_omp_clause): Print null_pointer_node
as omp_all_memory.
gcc/c-family/
* c-common.h (enum rid): Add RID_OMP_ALL_MEMORY.
* c-omp.cc (c_finish_omp_depobj): Don't build_fold_addr_expr
if null_pointer_node.
gcc/c/
* c-parser.cc (c_parse_init): Register omp_all_memory as keyword
if flag_openmp.
(c_parser_postfix_expression): Diagnose uses of omp_all_memory
in postfix expressions.
(c_parser_omp_variable_list): Handle omp_all_memory in depend
clause.
* c-typeck.cc (c_finish_omp_clauses): Handle omp_all_memory
keyword in depend clause as null_pointer_node, diagnose invalid
uses.
gcc/cp/
* lex.cc (init_reswords): Register omp_all_memory as keyword
if flag_openmp.
* parser.cc (cp_parser_primary_expression): Diagnose uses of
omp_all_memory in postfix expressions.
(cp_parser_omp_var_list_no_open): Handle omp_all_memory in depend
clause.
* semantics.cc (finish_omp_clauses): Handle omp_all_memory
keyword in depend clause as null_pointer_node, diagnose invalid
uses.
* pt.cc (tsubst_omp_clause_decl): Pass through omp_all_memory.
gcc/testsuite/
* c-c++-common/gomp/all-memory-1.c: New test.
* c-c++-common/gomp/all-memory-2.c: New test.
* c-c++-common/gomp/all-memory-3.c: New test.
* g++.dg/gomp/all-memory-1.C: New test.
* g++.dg/gomp/all-memory-2.C: New test.
libgomp/
* libgomp.h (struct gomp_task): Add depend_all_memory member.
* task.c (gomp_init_task): Initialize depend_all_memory.
(gomp_task_handle_depend): Handle omp_all_memory.
(gomp_task_run_post_handle_depend_hash): Clear
parent->depend_all_memory if equal to current task.
(gomp_task_maybe_wait_for_dependencies): Handle omp_all_memory.
* testsuite/libgomp.c-c++-common/depend-1.c: New test.
* testsuite/libgomp.c-c++-common/depend-2.c: New test.
* testsuite/libgomp.c-c++-common/depend-3.c: New test.
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