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* [gcc r13-724] openmp: Add taskwait nowait depend support [PR105378]
@ 2022-05-24 7:15 Jakub Jelinek
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From: Jakub Jelinek @ 2022-05-24 7:15 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:b43836914bdc2a37563cf31359b2c4803bfe4374
commit r13-724-gb43836914bdc2a37563cf31359b2c4803bfe4374
Author: Jakub Jelinek <jakub@redhat.com>
Date: Tue May 24 09:12:44 2022 +0200
openmp: Add taskwait nowait depend support [PR105378]
This patch adds support for (so far C/C++)
#pragma omp taskwait nowait depend(...)
directive, which is like
#pragma omp task depend(...)
;
but slightly optimized on the library side, so that it creates
the task only for the purpose of dependency tracking and doesn't actually
schedule it and wait for it when the dependencies are satisfied, instead
makes its dependencies satisfied right away.
2022-05-24 Jakub Jelinek <jakub@redhat.com>
PR c/105378
gcc/
* omp-builtins.def (BUILT_IN_GOMP_TASKWAIT_DEPEND_NOWAIT): New
builtin.
* gimplify.cc (gimplify_omp_task): Diagnose taskwait with nowait
clause but no depend clauses.
* omp-expand.cc (expand_taskwait_call): Use
BUILT_IN_GOMP_TASKWAIT_DEPEND_NOWAIT rather than
BUILT_IN_GOMP_TASKWAIT_DEPEND if nowait clause is present.
gcc/c/
* c-parser.cc (OMP_TASKWAIT_CLAUSE_MASK): Add nowait clause.
gcc/cp/
* parser.cc (OMP_TASKWAIT_CLAUSE_MASK): Add nowait clause.
gcc/testsuite/
* c-c++-common/gomp/taskwait-depend-nowait-1.c: New test.
libgomp/
* libgomp_g.h (GOMP_taskwait_depend_nowait): Declare.
* libgomp.map (GOMP_taskwait_depend_nowait): Export at GOMP_5.1.1.
* task.c (empty_task): New function.
(gomp_task_run_post_handle_depend_hash): Declare earlier.
(gomp_task_run_post_handle_depend): Declare.
(GOMP_task): Optimize fn == empty_task if there is nothing to wait
for.
(gomp_task_run_post_handle_dependers): Optimize task->fn == empty_task.
(GOMP_taskwait_depend_nowait): New function.
* testsuite/libgomp.c-c++-common/taskwait-depend-nowait-1.c: New test.
Diff:
---
gcc/c/c-parser.cc | 3 +-
gcc/cp/parser.cc | 3 +-
gcc/gimplify.cc | 31 ++++++++++----
gcc/omp-builtins.def | 3 ++
gcc/omp-expand.cc | 8 ++--
.../c-c++-common/gomp/taskwait-depend-nowait-1.c | 17 ++++++++
libgomp/libgomp.map | 5 +++
libgomp/libgomp_g.h | 1 +
libgomp/task.c | 47 +++++++++++++++++++++-
.../taskwait-depend-nowait-1.c | 39 ++++++++++++++++++
10 files changed, 143 insertions(+), 14 deletions(-)
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 8df8f60ef21..492d995a281 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -20453,7 +20453,8 @@ c_parser_omp_task (location_t loc, c_parser *parser, bool *if_p)
*/
#define OMP_TASKWAIT_CLAUSE_MASK \
- (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_DEPEND)
+ ( (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_DEPEND) \
+ | (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_NOWAIT))
static void
c_parser_omp_taskwait (c_parser *parser)
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 24585c1c013..868b8610d60 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -43793,7 +43793,8 @@ cp_parser_omp_task (cp_parser *parser, cp_token *pragma_tok, bool *if_p)
# pragma omp taskwait taskwait-clause[opt] new-line */
#define OMP_TASKWAIT_CLAUSE_MASK \
- (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_DEPEND)
+ ( (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_DEPEND) \
+ | (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_NOWAIT))
static void
cp_parser_omp_taskwait (cp_parser *parser, cp_token *pragma_tok)
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index 98f554491e2..cd1796643d7 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -12319,17 +12319,34 @@ gimplify_omp_task (tree *expr_p, gimple_seq *pre_p)
tree expr = *expr_p;
gimple *g;
gimple_seq body = NULL;
+ bool nowait = false;
+ bool has_depend = false;
if (OMP_TASK_BODY (expr) == NULL_TREE)
- for (tree c = OMP_TASK_CLAUSES (expr); c; c = OMP_CLAUSE_CHAIN (c))
- if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_DEPEND
- && OMP_CLAUSE_DEPEND_KIND (c) == OMP_CLAUSE_DEPEND_MUTEXINOUTSET)
+ {
+ for (tree c = OMP_TASK_CLAUSES (expr); c; c = OMP_CLAUSE_CHAIN (c))
+ if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_DEPEND)
+ {
+ has_depend = true;
+ if (OMP_CLAUSE_DEPEND_KIND (c) == OMP_CLAUSE_DEPEND_MUTEXINOUTSET)
+ {
+ error_at (OMP_CLAUSE_LOCATION (c),
+ "%<mutexinoutset%> kind in %<depend%> clause on a "
+ "%<taskwait%> construct");
+ break;
+ }
+ }
+ else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_NOWAIT)
+ nowait = true;
+ if (nowait && !has_depend)
{
- error_at (OMP_CLAUSE_LOCATION (c),
- "%<mutexinoutset%> kind in %<depend%> clause on a "
- "%<taskwait%> construct");
- break;
+ error_at (EXPR_LOCATION (expr),
+ "%<taskwait%> construct with %<nowait%> clause but no "
+ "%<depend%> clauses");
+ *expr_p = NULL_TREE;
+ return;
}
+ }
gimplify_scan_omp_clauses (&OMP_TASK_CLAUSES (expr), pre_p,
omp_find_clause (OMP_TASK_CLAUSES (expr),
diff --git a/gcc/omp-builtins.def b/gcc/omp-builtins.def
index cfa6483c7ae..ee5213eedcf 100644
--- a/gcc/omp-builtins.def
+++ b/gcc/omp-builtins.def
@@ -89,6 +89,9 @@ DEF_GOMP_BUILTIN (BUILT_IN_GOMP_TASKWAIT, "GOMP_taskwait",
BT_FN_VOID, ATTR_NOTHROW_LEAF_LIST)
DEF_GOMP_BUILTIN (BUILT_IN_GOMP_TASKWAIT_DEPEND, "GOMP_taskwait_depend",
BT_FN_VOID_PTR, ATTR_NOTHROW_LEAF_LIST)
+DEF_GOMP_BUILTIN (BUILT_IN_GOMP_TASKWAIT_DEPEND_NOWAIT,
+ "GOMP_taskwait_depend_nowait",
+ BT_FN_VOID_PTR, ATTR_NOTHROW_LEAF_LIST)
DEF_GOMP_BUILTIN (BUILT_IN_GOMP_TASKYIELD, "GOMP_taskyield",
BT_FN_VOID, ATTR_NOTHROW_LEAF_LIST)
DEF_GOMP_BUILTIN (BUILT_IN_GOMP_TASKGROUP_START, "GOMP_taskgroup_start",
diff --git a/gcc/omp-expand.cc b/gcc/omp-expand.cc
index 5729a20397d..0821b8d0688 100644
--- a/gcc/omp-expand.cc
+++ b/gcc/omp-expand.cc
@@ -916,10 +916,12 @@ expand_taskwait_call (basic_block bb, gomp_task *entry_stmt)
depend = OMP_CLAUSE_DECL (depend);
+ bool nowait = omp_find_clause (clauses, OMP_CLAUSE_NOWAIT) != NULL_TREE;
gimple_stmt_iterator gsi = gsi_last_nondebug_bb (bb);
- tree t
- = build_call_expr (builtin_decl_explicit (BUILT_IN_GOMP_TASKWAIT_DEPEND),
- 1, depend);
+ enum built_in_function f = (nowait
+ ? BUILT_IN_GOMP_TASKWAIT_DEPEND_NOWAIT
+ : BUILT_IN_GOMP_TASKWAIT_DEPEND);
+ tree t = build_call_expr (builtin_decl_explicit (f), 1, depend);
force_gimple_operand_gsi (&gsi, t, true, NULL_TREE,
false, GSI_CONTINUE_LINKING);
diff --git a/gcc/testsuite/c-c++-common/gomp/taskwait-depend-nowait-1.c b/gcc/testsuite/c-c++-common/gomp/taskwait-depend-nowait-1.c
new file mode 100644
index 00000000000..54df0235bde
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/taskwait-depend-nowait-1.c
@@ -0,0 +1,17 @@
+void
+foo (int *p)
+{
+ #pragma omp taskwait depend(iterator(i = 0:16) , in : p[i]) nowait depend(out : p[32])
+}
+
+void
+bar (int *p)
+{
+ #pragma omp taskwait depend(mutexinoutset : p[0]) nowait /* { dg-error "'mutexinoutset' kind in 'depend' clause on a 'taskwait' construct" } */
+}
+
+void
+baz (void)
+{
+ #pragma omp taskwait nowait /* { dg-error "'taskwait' construct with 'nowait' clause but no 'depend' clauses" } */
+}
diff --git a/libgomp/libgomp.map b/libgomp/libgomp.map
index 6334fdcce53..46d5f10f3e1 100644
--- a/libgomp/libgomp.map
+++ b/libgomp/libgomp.map
@@ -410,6 +410,11 @@ GOMP_5.1 {
GOMP_teams4;
} GOMP_5.0.1;
+GOMP_5.1.1 {
+ global:
+ GOMP_taskwait_depend_nowait;
+} GOMP_5.1;
+
OACC_2.0 {
global:
acc_get_num_devices;
diff --git a/libgomp/libgomp_g.h b/libgomp/libgomp_g.h
index 09674a1225c..84b9f2cfed6 100644
--- a/libgomp/libgomp_g.h
+++ b/libgomp/libgomp_g.h
@@ -305,6 +305,7 @@ extern void GOMP_taskloop_ull (void (*) (void *), void *,
unsigned long long);
extern void GOMP_taskwait (void);
extern void GOMP_taskwait_depend (void **);
+extern void GOMP_taskwait_depend_nowait (void **);
extern void GOMP_taskyield (void);
extern void GOMP_taskgroup_start (void);
extern void GOMP_taskgroup_end (void);
diff --git a/libgomp/task.c b/libgomp/task.c
index 6b11a8f02ef..7925e5873c4 100644
--- a/libgomp/task.c
+++ b/libgomp/task.c
@@ -460,6 +460,17 @@ gomp_task_handle_depend (struct gomp_task *task, struct gomp_task *parent,
}
}
+/* Body of empty task like taskwait nowait depend. */
+
+static void
+empty_task (void *data __attribute__((unused)))
+{
+}
+
+static void gomp_task_run_post_handle_depend_hash (struct gomp_task *);
+static inline size_t gomp_task_run_post_handle_depend (struct gomp_task *,
+ struct gomp_team *);
+
/* Called when encountering an explicit task directive. If IF_CLAUSE is
false, then we must not delay in executing the task. If UNTIED is true,
then the task may be executed by any member of the team.
@@ -681,6 +692,18 @@ GOMP_task (void (*fn) (void *), void *data, void (*cpyfn) (void *, void *),
gomp_mutex_unlock (&team->task_lock);
return;
}
+ /* Check for taskwait nowait depend which doesn't need to wait for
+ anything. */
+ if (__builtin_expect (fn == empty_task, 0))
+ {
+ if (taskgroup)
+ taskgroup->num_children--;
+ gomp_task_run_post_handle_depend_hash (task);
+ gomp_mutex_unlock (&team->task_lock);
+ gomp_finish_task (task);
+ free (task);
+ return;
+ }
}
priority_queue_insert (PQ_CHILDREN, &parent->children_queue,
@@ -839,8 +862,6 @@ GOMP_PLUGIN_target_task_completion (void *data)
gomp_mutex_unlock (&team->task_lock);
}
-static void gomp_task_run_post_handle_depend_hash (struct gomp_task *);
-
/* Called for nowait target tasks. */
bool
@@ -1357,6 +1378,18 @@ gomp_task_run_post_handle_dependers (struct gomp_task *child_task,
continue;
struct gomp_taskgroup *taskgroup = task->taskgroup;
+ if (__builtin_expect (task->fn == empty_task, 0))
+ {
+ if (!parent)
+ task->parent = NULL;
+ if (gomp_task_run_post_handle_depend (task, team))
+ ++ret;
+ if (taskgroup)
+ taskgroup->num_children--;
+ gomp_finish_task (task);
+ free (task);
+ continue;
+ }
if (parent)
{
priority_queue_insert (PQ_CHILDREN, &parent->children_queue,
@@ -1832,6 +1865,16 @@ GOMP_taskwait_depend (void **depend)
gomp_task_maybe_wait_for_dependencies (depend);
}
+/* Called when encountering a taskwait directive with nowait and depend
+ clause(s). Create a possibly deferred task construct with empty body. */
+
+void
+GOMP_taskwait_depend_nowait (void **depend)
+{
+ ialias_call (GOMP_task) (empty_task, "", NULL, 0, 1, true,
+ GOMP_TASK_FLAG_DEPEND, depend, 0, NULL);
+}
+
/* An undeferred task is about to run. Wait for all tasks that this
undeferred task depends on.
diff --git a/libgomp/testsuite/libgomp.c-c++-common/taskwait-depend-nowait-1.c b/libgomp/testsuite/libgomp.c-c++-common/taskwait-depend-nowait-1.c
new file mode 100644
index 00000000000..3d1519ee70a
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c-c++-common/taskwait-depend-nowait-1.c
@@ -0,0 +1,39 @@
+#ifdef __cplusplus
+extern "C"
+#endif
+void abort (void);
+
+int
+main ()
+{
+ int a[64], b = 1;
+ #pragma omp parallel num_threads (4)
+ #pragma omp single
+ {
+ int i;
+ #pragma omp taskwait depend(in: a) nowait
+ #pragma omp taskwait depend(in: a) nowait
+ #pragma omp taskwait
+ #pragma omp taskgroup
+ {
+ #pragma omp taskwait depend(in: a) nowait
+ #pragma omp taskwait depend(in: a) nowait
+ }
+ for (i = 0; i < 64; ++i)
+ #pragma omp task depend(in: a) shared(a)
+ a[i] = i;
+ #pragma omp taskwait depend(inout: a) nowait
+ for (i = 0; i < 64; ++i)
+ #pragma omp task depend(inoutset: a) shared(a)
+ if (a[i] != i)
+ abort ();
+ else
+ a[i] = 2 * i + 1;
+ #pragma omp taskwait nowait depend(out: a) depend(in: b)
+ #pragma omp taskwait depend(inout: b)
+ for (i = 0; i < 64; ++i)
+ if (a[i] != 2 * i + 1)
+ abort ();
+ }
+ return 0;
+}
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