[flang] [llvm] [mlir] [flang][mlir][llvm][OpenMP] Add lowering and translation support for mergeable clause on task (PR #114662)

via llvm-commits llvm-commits at lists.llvm.org
Sat Nov 2 04:38:29 PDT 2024


https://github.com/NimishMishra created https://github.com/llvm/llvm-project/pull/114662

Add FIR generation and LLVMIR translation support for mergeable clause on task construct. A `__kmpc_task_allow_completion_event` call is emitted on the `mergeable` task, and the return value is stored in the `event_handle` (described by the mergeable clause).

>From a6929fcd163bf8c24733ae3ad81bac0ecc2e5467 Mon Sep 17 00:00:00 2001
From: Nimish Mishra <neelam.nimish at gmail.com>
Date: Sat, 2 Nov 2024 17:05:39 +0530
Subject: [PATCH] [flang][mlir][llvm][OpenMP] Add lowering and translation
 support for mergeable clause on task

---
 flang/lib/Lower/OpenMP/OpenMP.cpp               |  4 ++--
 flang/test/Lower/OpenMP/Todo/task_mergeable.f90 | 13 -------------
 flang/test/Lower/OpenMP/task.f90                |  8 ++++++++
 .../include/llvm/Frontend/OpenMP/OMPIRBuilder.h | 12 ++++++------
 llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp       | 17 +++++++++++------
 .../OpenMP/OpenMPToLLVMIRTranslation.cpp        |  4 ++--
 mlir/test/Target/LLVMIR/openmp-llvm.mlir        | 13 +++++++++++++
 mlir/test/Target/LLVMIR/openmp-todo.mlir        | 11 -----------
 8 files changed, 42 insertions(+), 40 deletions(-)
 delete mode 100644 flang/test/Lower/OpenMP/Todo/task_mergeable.f90

diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index 329cbf3d7539f5..c217903624a234 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -1336,8 +1336,8 @@ static void genTaskClauses(lower::AbstractConverter &converter,
   cp.processUntied(clauseOps);
   // TODO Support delayed privatization.
 
-  cp.processTODO<clause::Affinity, clause::Detach, clause::InReduction,
-                 clause::Mergeable>(loc, llvm::omp::Directive::OMPD_task);
+  cp.processTODO<clause::Affinity, clause::Detach, clause::InReduction>(
+      loc, llvm::omp::Directive::OMPD_task);
 }
 
 static void genTaskgroupClauses(lower::AbstractConverter &converter,
diff --git a/flang/test/Lower/OpenMP/Todo/task_mergeable.f90 b/flang/test/Lower/OpenMP/Todo/task_mergeable.f90
deleted file mode 100644
index ddc27487abfe9c..00000000000000
--- a/flang/test/Lower/OpenMP/Todo/task_mergeable.f90
+++ /dev/null
@@ -1,13 +0,0 @@
-! RUN: %not_todo_cmd bbc -emit-fir -fopenmp -o - %s 2>&1 | FileCheck %s
-! RUN: %not_todo_cmd %flang_fc1 -emit-fir -fopenmp -o - %s 2>&1 | FileCheck %s
-
-!===============================================================================
-! `mergeable` clause
-!===============================================================================
-
-! CHECK: not yet implemented: Unhandled clause MERGEABLE in TASK construct
-subroutine omp_task_mergeable()
-  !$omp task mergeable
-  call foo()
-  !$omp end task
-end subroutine omp_task_mergeable
diff --git a/flang/test/Lower/OpenMP/task.f90 b/flang/test/Lower/OpenMP/task.f90
index 4f00f261fe57df..27cc379ba0d463 100644
--- a/flang/test/Lower/OpenMP/task.f90
+++ b/flang/test/Lower/OpenMP/task.f90
@@ -245,3 +245,11 @@ subroutine task_multiple_clauses()
   !CHECK: omp.terminator
   !$omp end task
 end subroutine task_multiple_clauses
+
+subroutine task_mergeable()
+!CHECK: omp.task mergeable {
+!CHECK: omp.terminator
+!CHECK: }
+ !$omp task mergeable
+ !$omp end task
+end subroutine
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
index 3afb9d84278e81..a97deafa3683cf 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h
@@ -1262,12 +1262,12 @@ class OpenMPIRBuilder {
   ///                    cannot be resumed until execution of the structured
   ///                    block that is associated with the generated task is
   ///                    completed.
-  InsertPointOrErrorTy createTask(const LocationDescription &Loc,
-                                  InsertPointTy AllocaIP,
-                                  BodyGenCallbackTy BodyGenCB, bool Tied = true,
-                                  Value *Final = nullptr,
-                                  Value *IfCondition = nullptr,
-                                  SmallVector<DependData> Dependencies = {});
+  /// \param Mergeable	 If the given task is `mergeable`
+  InsertPointOrErrorTy
+  createTask(const LocationDescription &Loc, InsertPointTy AllocaIP,
+             BodyGenCallbackTy BodyGenCB, bool Tied = true,
+             Value *Final = nullptr, Value *IfCondition = nullptr,
+             SmallVector<DependData> Dependencies = {}, bool Mergeable = false);
 
   /// Generator for the taskgroup construct
   ///
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index d2e4dc1c85dfd2..d5d5a39897229d 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -1816,11 +1816,10 @@ static Value *emitTaskDependencies(
   return DepArray;
 }
 
-OpenMPIRBuilder::InsertPointOrErrorTy
-OpenMPIRBuilder::createTask(const LocationDescription &Loc,
-                            InsertPointTy AllocaIP, BodyGenCallbackTy BodyGenCB,
-                            bool Tied, Value *Final, Value *IfCondition,
-                            SmallVector<DependData> Dependencies) {
+OpenMPIRBuilder::InsertPointOrErrorTy OpenMPIRBuilder::createTask(
+    const LocationDescription &Loc, InsertPointTy AllocaIP,
+    BodyGenCallbackTy BodyGenCB, bool Tied, Value *Final, Value *IfCondition,
+    SmallVector<DependData> Dependencies, bool Mergeable) {
 
   if (!updateToLocation(Loc))
     return InsertPointTy();
@@ -1866,7 +1865,8 @@ OpenMPIRBuilder::createTask(const LocationDescription &Loc,
       Builder, AllocaIP, ToBeDeleted, TaskAllocaIP, "global.tid", false));
 
   OI.PostOutlineCB = [this, Ident, Tied, Final, IfCondition, Dependencies,
-                      TaskAllocaBB, ToBeDeleted](Function &OutlinedFn) mutable {
+                      Mergeable, TaskAllocaBB,
+                      ToBeDeleted](Function &OutlinedFn) mutable {
     // Replace the Stale CI by appropriate RTL function call.
     assert(OutlinedFn.getNumUses() == 1 &&
            "there must be a single user for the outlined function");
@@ -1891,6 +1891,8 @@ OpenMPIRBuilder::createTask(const LocationDescription &Loc,
     // Task is untied iff (Flags & 1) == 0.
     // Task is final iff (Flags & 2) == 2.
     // Task is not final iff (Flags & 2) == 0.
+    // Task is mergeable iff (Flags & 4) == 4.
+    // Task is not mergeable iff (Flags & 4) == 0.
     // TODO: Handle the other flags.
     Value *Flags = Builder.getInt32(Tied);
     if (Final) {
@@ -1899,6 +1901,9 @@ OpenMPIRBuilder::createTask(const LocationDescription &Loc,
       Flags = Builder.CreateOr(FinalFlag, Flags);
     }
 
+    if (Mergeable)
+      Flags = Builder.CreateOr(Builder.getInt32(4), Flags);
+
     // Argument - `sizeof_kmp_task_t` (TaskSize)
     // Tasksize refers to the size in bytes of kmp_task_t data structure
     // including private vars accessed in task.
diff --git a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
index dca29f55661b0c..5e9f9c341e215d 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp
@@ -255,7 +255,6 @@ static LogicalResult checkImplementationStatus(Operation &op) {
       .Case([&](omp::TaskOp op) {
         checkAllocate(op, result);
         checkInReduction(op, result);
-        checkMergeable(op, result);
         checkPriority(op, result);
         checkPrivate(op, result);
         checkUntied(op, result);
@@ -1507,7 +1506,8 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder,
       moduleTranslation.getOpenMPBuilder()->createTask(
           ompLoc, allocaIP, bodyCB, !taskOp.getUntied(),
           moduleTranslation.lookupValue(taskOp.getFinal()),
-          moduleTranslation.lookupValue(taskOp.getIfExpr()), dds);
+          moduleTranslation.lookupValue(taskOp.getIfExpr()), dds,
+          taskOp.getMergeable());
 
   if (failed(handleError(afterIP, *taskOp)))
     return failure();
diff --git a/mlir/test/Target/LLVMIR/openmp-llvm.mlir b/mlir/test/Target/LLVMIR/openmp-llvm.mlir
index 49f9f3562c78b5..c477e983f0a1b6 100644
--- a/mlir/test/Target/LLVMIR/openmp-llvm.mlir
+++ b/mlir/test/Target/LLVMIR/openmp-llvm.mlir
@@ -2952,6 +2952,19 @@ module attributes {omp.is_target_device = true} {
 
 // -----
 
+// Third argument is 5: essentially (4 || 1)
+// signifying this task is TIED and MERGEABLE
+
+// CHECK: {{.*}} = call ptr @__kmpc_omp_task_alloc(ptr @1, i32 %omp_global_thread_num, i32 5, i64 40, i64 0, ptr @omp_task_mergeable..omp_par)
+llvm.func @omp_task_mergeable() {
+  omp.task mergeable {
+    omp.terminator
+  }
+  llvm.return
+}
+
+// -----
+
 llvm.func external @foo_before() -> ()
 llvm.func external @foo() -> ()
 llvm.func external @foo_after() -> ()
diff --git a/mlir/test/Target/LLVMIR/openmp-todo.mlir b/mlir/test/Target/LLVMIR/openmp-todo.mlir
index 3c9bd9031c3e85..4fa857c9ed1a6c 100644
--- a/mlir/test/Target/LLVMIR/openmp-todo.mlir
+++ b/mlir/test/Target/LLVMIR/openmp-todo.mlir
@@ -447,17 +447,6 @@ llvm.func @task_in_reduction(%x : !llvm.ptr) {
 
 // -----
 
-llvm.func @task_mergeable() {
-  // expected-error at below {{mergeable clause not yet supported}}
-  // expected-error at below {{LLVM Translation failed for operation: omp.task}}
-  omp.task mergeable {
-    omp.terminator
-  }
-  llvm.return
-}
-
-// -----
-
 llvm.func @task_priority(%x : i32) {
   // expected-error at below {{priority clause not yet supported}}
   // expected-error at below {{LLVM Translation failed for operation: omp.task}}



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