[mlir][llvm] Translation support for task detach

llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h

@@ -1262,12 +1262,15 @@ class OpenMPIRBuilder {
   ///                    cannot be resumed until execution of the structured
   ///                    block that is associated with the generated task is
   ///                    completed.
+  /// \param EventHandle If present, signifies the event handle as part of
+  ///			 the detach clause
   /// \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);
+             SmallVector<DependData> Dependencies = {}, bool Mergeable = false,
+             Value *EventHandle = nullptr);
 
   /// Generator for the taskgroup construct
   ///

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

@@ -1818,7 +1818,7 @@ static Value *emitTaskDependencies(
 OpenMPIRBuilder::InsertPointOrErrorTy OpenMPIRBuilder::createTask(
     const LocationDescription &Loc, InsertPointTy AllocaIP,
     BodyGenCallbackTy BodyGenCB, bool Tied, Value *Final, Value *IfCondition,
-    SmallVector<DependData> Dependencies, bool Mergeable) {
+    SmallVector<DependData> Dependencies, bool Mergeable, Value *EventHandle) {
 
   if (!updateToLocation(Loc))
     return InsertPointTy();
@@ -1864,7 +1864,7 @@ OpenMPIRBuilder::InsertPointOrErrorTy OpenMPIRBuilder::createTask(
       Builder, AllocaIP, ToBeDeleted, TaskAllocaIP, "global.tid", false));
 
   OI.PostOutlineCB = [this, Ident, Tied, Final, IfCondition, Dependencies,
-                      Mergeable, TaskAllocaBB,
+                      Mergeable, EventHandle, TaskAllocaBB,
                       ToBeDeleted](Function &OutlinedFn) mutable {
     // Replace the Stale CI by appropriate RTL function call.
     assert(OutlinedFn.getNumUses() == 1 &&
@@ -1935,6 +1935,20 @@ OpenMPIRBuilder::InsertPointOrErrorTy OpenMPIRBuilder::createTask(
                       /*sizeof_task=*/TaskSize, /*sizeof_shared=*/SharedsSize,
                       /*task_func=*/&OutlinedFn});
 
+    // Emit detach clause initialization.
+    // evt = (typeof(evt))__kmpc_task_allow_completion_event(loc, tid,
+    // task_descriptor);
+    if (EventHandle) {
+      Function *TaskDetachFn = getOrCreateRuntimeFunctionPtr(
+          OMPRTL___kmpc_task_allow_completion_event);
+      llvm::Value *EventVal =
+          Builder.CreateCall(TaskDetachFn, {Ident, ThreadID, TaskData});
+      llvm::Value *EventHandleAddr =
+          Builder.CreatePointerBitCastOrAddrSpaceCast(EventHandle,
+                                                      Builder.getPtrTy(0));
+      EventVal = Builder.CreatePtrToInt(EventVal, Builder.getInt64Ty());
+      Builder.CreateStore(EventVal, EventHandleAddr);
+    }
     // Copy the arguments for outlined function
     if (HasShareds) {
       Value *Shareds = StaleCI->getArgOperand(1);

mlir/include/mlir/Dialect/OpenMP/OpenMPClauses.td

@@ -909,6 +909,34 @@ class OpenMP_ParallelizationLevelClauseSkip<
 
 def OpenMP_ParallelizationLevelClause : OpenMP_ParallelizationLevelClauseSkip<>;
 
+//===----------------------------------------------------------------------===//
+// OpenMPV5.2: [12.5.2] `detach` clause
+//===----------------------------------------------------------------------===//
+
+class OpenMP_DetachClauseSkip<
+    bit traits = false, bit arguments = false, bit assemblyFormat = false,
+    bit description = false, bit extraClassDeclaration = false>
+    : OpenMP_Clause<traits, arguments, assemblyFormat, description,
+                    extraClassDeclaration> {
+
+  let traits = [BlockArgOpenMPOpInterface];
+
+  let arguments = (ins Optional<OpenMP_PointerLikeType>:$event_handle);
+
+  let optAssemblyFormat = [{
+		`detach` `(` $event_handle `:` type($event_handle) `)`
+	}];
+
+  let description = [{
+		The detach clause specifies that the task generated by the construct on which it appears is a
+	detachable task. A new allow-completion event is created and connected to the completion of the
+	associated task region. The original event-handle is updated to represent that allow-completion
+	event before the task data environment is created.
+	}];
+}
+
+def OpenMP_DetachClause : OpenMP_DetachClauseSkip<>;
+
 //===----------------------------------------------------------------------===//
 // V5.2: [12.4] `priority` clause
 //===----------------------------------------------------------------------===//

mlir/include/mlir/Dialect/OpenMP/OpenMPOps.td

@@ -657,15 +657,18 @@ def DistributeOp : OpenMP_Op<"distribute", traits = [
 // 2.10.1 task Construct
 //===----------------------------------------------------------------------===//
 
-def TaskOp : OpenMP_Op<"task", traits = [
-    AttrSizedOperandSegments, AutomaticAllocationScope,
-    OutlineableOpenMPOpInterface
-  ], clauses = [
-    // TODO: Complete clause list (affinity, detach).
-    OpenMP_AllocateClause, OpenMP_DependClause, OpenMP_FinalClause,
-    OpenMP_IfClause, OpenMP_InReductionClause, OpenMP_MergeableClause,
-    OpenMP_PriorityClause, OpenMP_PrivateClause, OpenMP_UntiedClause
-  ], singleRegion = true> {
+def TaskOp
+    : OpenMP_Op<"task",
+                traits = [AttrSizedOperandSegments, AutomaticAllocationScope,
+                          OutlineableOpenMPOpInterface],
+                clauses = [
+                    // TODO: Complete clause list (affinity, detach).
+                    OpenMP_AllocateClause, OpenMP_DependClause,
+                    OpenMP_FinalClause, OpenMP_IfClause,
+                    OpenMP_InReductionClause, OpenMP_MergeableClause,
+                    OpenMP_PriorityClause, OpenMP_PrivateClause,
+                    OpenMP_UntiedClause, OpenMP_DetachClause],
+                singleRegion = true> {
   let summary = "task construct";
   let description = [{
     The task construct defines an explicit task.

mlir/lib/Dialect/OpenMP/IR/OpenMPDialect.cpp

@@ -2303,7 +2303,7 @@ void TaskOp::build(OpBuilder &builder, OperationState &state,
                 makeArrayAttr(ctx, clauses.inReductionSyms), clauses.mergeable,
                 clauses.priority, /*private_vars=*/clauses.privateVars,
                 /*private_syms=*/makeArrayAttr(ctx, clauses.privateSyms),
-                clauses.untied);
+                clauses.untied, clauses.eventHandle);
 }
 
 LogicalResult TaskOp::verify() {

mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp

@@ -1703,7 +1703,8 @@ convertOmpTaskOp(omp::TaskOp taskOp, llvm::IRBuilderBase &builder,
           ompLoc, allocaIP, bodyCB, !taskOp.getUntied(),
           moduleTranslation.lookupValue(taskOp.getFinal()),
           moduleTranslation.lookupValue(taskOp.getIfExpr()), dds,
-          taskOp.getMergeable());
+          taskOp.getMergeable(),
+          moduleTranslation.lookupValue(taskOp.getEventHandle()));
 
   if (failed(handleError(afterIP, *taskOp)))
     return failure();

mlir/test/Dialect/OpenMP/invalid.mlir

@@ -1634,7 +1634,7 @@ func.func @omp_single_copyprivate(%data_var : memref<i32>) -> () {
 // -----
 
 func.func @omp_task_depend(%data_var: memref<i32>) {
-  // expected-error @below {{op expected as many depend values as depend variables}}
+  // expected-error @below {{'omp.task' op operand count (1) does not match with the total size (0) specified in attribute 'operandSegmentSizes'}}
     "omp.task"(%data_var) ({
       "omp.terminator"() : () -> ()
     }) {depend_kinds = [], operandSegmentSizes = array<i32: 0, 0, 1, 0, 0, 0, 0, 0>} : (memref<i32>) -> ()

mlir/test/Dialect/OpenMP/ops.mlir

@@ -1975,8 +1975,8 @@ func.func @omp_single_copyprivate(%data_var: memref<i32>) {
 }
 
 // CHECK-LABEL: @omp_task
-// CHECK-SAME: (%[[bool_var:.*]]: i1, %[[i64_var:.*]]: i64, %[[i32_var:.*]]: i32, %[[data_var:.*]]: memref<i32>)
-func.func @omp_task(%bool_var: i1, %i64_var: i64, %i32_var: i32, %data_var: memref<i32>) {
+// CHECK-SAME: (%[[bool_var:.*]]: i1, %[[i64_var:.*]]: i64, %[[i32_var:.*]]: i32, %[[data_var:.*]]: memref<i32>, %[[event_handle:.*]]: !llvm.ptr)
+func.func @omp_task(%bool_var: i1, %i64_var: i64, %i32_var: i32, %data_var: memref<i32>, %event_handle : !llvm.ptr) {
 
   // Checking simple task
   // CHECK: omp.task {
@@ -2054,7 +2054,11 @@ func.func @omp_task(%bool_var: i1, %i64_var: i64, %i32_var: i32, %data_var: memr
     // CHECK: omp.terminator
     omp.terminator
   }
-
+  // Checking detach clause
+  // CHECK: omp.task detach(%[[event_handle]] : !llvm.ptr)
+  omp.task detach(%event_handle : !llvm.ptr){
+     omp.terminator
+  }
   // Checking multiple clauses
   // CHECK: omp.task allocate(%[[data_var]] : memref<i32> -> %[[data_var]] : memref<i32>)
   omp.task allocate(%data_var : memref<i32> -> %data_var : memref<i32>)

mlir/test/Target/LLVMIR/openmp-llvm.mlir

@@ -2505,6 +2505,23 @@ llvm.mlir.global internal @_QFsubEx() : i32
 
 // -----
 
+// CHECK-LABEL: define void @omp_task_detach
+// CHECK-SAME: (ptr %[[event_handle:.*]])
+llvm.func @omp_task_detach(%event_handle : !llvm.ptr){
+   // CHECK: %[[omp_global_thread_num:.+]] = call i32 @__kmpc_global_thread_num({{.+}})
+   // CHECK: %[[task_data:.+]] = call ptr @__kmpc_omp_task_alloc
+   // CHECK: %[[return_val:.*]] = call ptr @__kmpc_task_allow_completion_event(ptr {{.*}}, i32 %[[omp_global_thread_num]], ptr %[[task_data]])
+   // CHECK: %[[conv:.*]] = ptrtoint ptr %[[return_val]] to i64
+   // CHECK: store i64 %[[conv]], ptr %[[event_handle]], align 4
+   // CHECK: call i32 @__kmpc_omp_task(ptr @{{.+}}, i32 %[[omp_global_thread_num]], ptr %[[task_data]])
+   omp.task detach(%event_handle : !llvm.ptr){
+     omp.terminator
+   }
+   llvm.return
+}
+
+// -----
+
 // CHECK-LABEL: define void @omp_task
 // CHECK-SAME: (i32 %[[x:.+]], i32 %[[y:.+]], ptr %[[zaddr:.+]])
 llvm.func @omp_task(%x: i32, %y: i32, %zaddr: !llvm.ptr) {