[OpenMP] Fix cancellation point in task with no cancel

[Hahnfeld]

Summary

With tasks, the cancel may happen in another task. This has a different
region info which means that we can't find it here.

[ABataev]

LG

lib/CodeGen/CGOpenMPRuntime.cpp

void CGOpenMPRuntime::emitCancellationPointCall(
     CodeGenFunction &CGF, SourceLocation Loc,
     OpenMPDirectiveKind CancelRegion) {
   if (!CGF.HaveInsertPoint())
     return;
   // Build call kmp_int32 __kmpc_cancellationpoint(ident_t *loc, kmp_int32
   // global_tid, kmp_int32 cncl_kind);
   if (auto *OMPRegionInfo =
           dyn_cast_or_null<CGOpenMPRegionInfo>(CGF.CapturedStmtInfo)) {
-    if (OMPRegionInfo->hasCancel()) {
+    // For 'cancellation point taskgroup', the task region info may not have a
+    // cancel. This may instead happen in another adjacent task.
+    if (CancelRegion == OMPD_taskgroup || OMPRegionInfo->hasCancel()) {
       llvm::Value *Args[] = {
           emitUpdateLocation(CGF, Loc), getThreadID(CGF, Loc),
           CGF.Builder.getInt32(getCancellationKind(CancelRegion))};
       // Ignore return result until untied tasks are supported.
       auto *Result = CGF.EmitRuntimeCall(
           createRuntimeFunction(OMPRTL__kmpc_cancellationpoint), Args);
       // if (__kmpc_cancellationpoint()) {
       //   exit from construct;

test/OpenMP/cancellation_point_codegen.cpp

 // CHECK: call void @__kmpc_barrier(%ident_t*
 #pragma omp task
 {
 #pragma omp cancellation point taskgroup
 #pragma omp cancel taskgroup
 }
 // CHECK: call i8* @__kmpc_omp_task_alloc(
 // CHECK: call i32 @__kmpc_omp_task(
+#pragma omp task
+{
+#pragma omp cancellation point taskgroup
+}
+// CHECK: call i8* @__kmpc_omp_task_alloc(
+// CHECK: call i32 @__kmpc_omp_task(
 #pragma omp parallel sections
 {
   {
 #pragma omp cancellation point sections
 #pragma omp cancel sections
   }
 }
 // CHECK: call void (%ident_t*, i32, void (i32*, i32*, ...)*, ...) @__kmpc_fork_call(

 // CHECK: [[RES:%.+]] = call i32 @__kmpc_cancellationpoint(%ident_t* {{[^,]+}}, i32 {{[^,]+}}, i32 4)
 // CHECK: [[CMP:%.+]] = icmp ne i32 [[RES]], 0
 // CHECK: br i1 [[CMP]], label %[[EXIT:[^,]+]],
 // CHECK: [[EXIT]]
 // CHECK: br label %[[RETURN:.+]]
 // CHECK: [[RETURN]]
 // CHECK: ret i32 0
 
+// CHECK: define internal i32 @{{[^(]+}}(i32
+// CHECK: [[RES:%.+]] = call i32 @__kmpc_cancellationpoint(%ident_t* {{[^,]+}}, i32 {{[^,]+}}, i32 4)
+// CHECK: [[CMP:%.+]] = icmp ne i32 [[RES]], 0
+// CHECK: br i1 [[CMP]], label %[[EXIT:[^,]+]],
+// CHECK: [[EXIT]]
+// CHECK: br label %[[RETURN:.+]]
+// CHECK: [[RETURN]]
+// CHECK: ret i32 0
+
 // CHECK: define internal void @{{[^(]+}}(i32* {{[^,]+}}, i32* {{[^,]+}})
 // CHECK: call void @__kmpc_for_static_init_4(
 // CHECK: [[RES:%.+]] = call i32 @__kmpc_cancellationpoint(%ident_t* {{[^,]+}}, i32 [[GTID:%.+]], i32 3)
 // CHECK: [[CMP:%.+]] = icmp ne i32 [[RES]], 0
 // CHECK: br i1 [[CMP]], label %[[EXIT:[^,].+]], label %[[CONTINUE:.+]]
 // CHECK: [[EXIT]]
 // CHECK: br label
 // CHECK: [[CONTINUE]]