diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index 60c83586e468b..cbfe1e7235c10 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -1255,8 +1255,8 @@ static void genTaskClauses(lower::AbstractConverter &converter,
   cp.processUntied(clauseOps);
   // TODO Support delayed privatization.
 
-  cp.processTODO<clause::Affinity, clause::Detach, clause::InReduction>(
-      loc, llvm::omp::Directive::OMPD_task);
+  cp.processTODO<clause::Affinity, clause::Detach, clause::InReduction,
+                 clause::Mergeable>(loc, llvm::omp::Directive::OMPD_task);
 }
 
 static void genTaskgroupClauses(lower::AbstractConverter &converter,
@@ -2764,7 +2764,10 @@ static void genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
         !std::holds_alternative<clause::ThreadLimit>(clause.u) &&
         !std::holds_alternative<clause::Threads>(clause.u) &&
         !std::holds_alternative<clause::UseDeviceAddr>(clause.u) &&
-        !std::holds_alternative<clause::UseDevicePtr>(clause.u)) {
+        !std::holds_alternative<clause::UseDevicePtr>(clause.u) &&
+        !std::holds_alternative<clause::InReduction>(clause.u) &&
+        !std::holds_alternative<clause::Mergeable>(clause.u) &&
+        !std::holds_alternative<clause::TaskReduction>(clause.u)) {
       TODO(clauseLocation, "OpenMP Block construct clause");
     }
   }
diff --git a/flang/test/Lower/OpenMP/Todo/reduction-inscan.f90 b/flang/test/Lower/OpenMP/Todo/reduction-inscan.f90
new file mode 100644
index 0000000000000..c5f196fe09693
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/reduction-inscan.f90
@@ -0,0 +1,14 @@
+! 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
+
+! CHECK: not yet implemented: Reduction modifiers are not supported
+subroutine reduction_inscan()
+  integer :: i,j
+  i = 0
+
+  !$omp do reduction(inscan, +:i)
+  do j=1,10
+     i = i + 1
+  end do
+  !$omp end do
+end subroutine reduction_inscan
diff --git a/flang/test/Lower/OpenMP/Todo/reduction-task.f90 b/flang/test/Lower/OpenMP/Todo/reduction-task.f90
new file mode 100644
index 0000000000000..6707f65e1a4cc
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/reduction-task.f90
@@ -0,0 +1,12 @@
+! 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
+
+! CHECK: not yet implemented: Reduction modifiers are not supported
+subroutine reduction_task()
+  integer :: i
+  i = 0
+
+  !$omp parallel reduction(task, +:i)
+  i = i + 1
+  !$omp end parallel 
+end subroutine reduction_task
diff --git a/flang/test/Lower/OpenMP/Todo/target-inreduction.f90 b/flang/test/Lower/OpenMP/Todo/target-inreduction.f90
new file mode 100644
index 0000000000000..e5a9cffac5a11
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/target-inreduction.f90
@@ -0,0 +1,15 @@
+! RUN: %not_todo_cmd bbc -emit-fir -fopenmp -fopenmp-version=50 -o - %s 2>&1 | FileCheck %s
+! RUN: %not_todo_cmd %flang_fc1 -emit-fir -fopenmp -fopenmp-version=50 -o - %s 2>&1 | FileCheck %s
+
+!===============================================================================
+! `mergeable` clause
+!===============================================================================
+
+! CHECK: not yet implemented: Unhandled clause IN_REDUCTION in TARGET construct
+subroutine omp_target_inreduction()
+  integer i
+  i = 0
+  !$omp target in_reduction(+:i)
+  i = i + 1
+  !$omp end target
+end subroutine omp_target_inreduction
diff --git a/flang/test/Lower/OpenMP/Todo/task-inreduction.f90 b/flang/test/Lower/OpenMP/Todo/task-inreduction.f90
new file mode 100644
index 0000000000000..aeed680a6dba7
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/task-inreduction.f90
@@ -0,0 +1,15 @@
+! 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 IN_REDUCTION in TASK construct
+subroutine omp_task_in_reduction()
+  integer i
+  i = 0
+  !$omp task in_reduction(+:i)
+  i = i + 1
+  !$omp end task
+end subroutine omp_task_in_reduction
diff --git a/flang/test/Lower/OpenMP/Todo/task_mergeable.f90 b/flang/test/Lower/OpenMP/Todo/task_mergeable.f90
index 13145d92ccf90..ddc27487abfe9 100644
--- a/flang/test/Lower/OpenMP/Todo/task_mergeable.f90
+++ b/flang/test/Lower/OpenMP/Todo/task_mergeable.f90
@@ -5,7 +5,7 @@
 ! `mergeable` clause
 !===============================================================================
 
-! CHECK: not yet implemented: OpenMP Block construct clause
+! CHECK: not yet implemented: Unhandled clause MERGEABLE in TASK construct
 subroutine omp_task_mergeable()
   !$omp task mergeable
   call foo()
diff --git a/flang/test/Lower/OpenMP/Todo/taskgroup-task-reduction.f90 b/flang/test/Lower/OpenMP/Todo/taskgroup-task-reduction.f90
new file mode 100644
index 0000000000000..1cb471d784d76
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/taskgroup-task-reduction.f90
@@ -0,0 +1,10 @@
+! RUN: %not_todo_cmd bbc -emit-fir -fopenmp -o - %s -fopenmp-version=50 2>&1 | FileCheck %s
+! RUN: %not_todo_cmd %flang_fc1 -emit-fir -fopenmp -o - %s -fopenmp-version=50 2>&1 | FileCheck %s
+
+! CHECK: not yet implemented: Unhandled clause TASK_REDUCTION in TASKGROUP construct
+subroutine omp_taskgroup_task_reduction
+  integer :: res
+  !$omp taskgroup task_reduction(+:res)
+  res = res + 1
+  !$omp end taskgroup
+end subroutine omp_taskgroup_task_reduction
diff --git a/flang/test/Lower/OpenMP/Todo/taskloop.f90 b/flang/test/Lower/OpenMP/Todo/taskloop.f90
new file mode 100644
index 0000000000000..aca050584cbbe
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/taskloop.f90
@@ -0,0 +1,13 @@
+! RUN: %not_todo_cmd bbc -emit-fir -fopenmp -o - %s -fopenmp-version=50 2>&1 | FileCheck %s
+! RUN: %not_todo_cmd %flang_fc1 -emit-fir -fopenmp -o - %s -fopenmp-version=50 2>&1 | FileCheck %s
+
+! CHECK: not yet implemented: Taskloop construct
+subroutine omp_taskloop
+  integer :: res, i
+  !$omp taskloop
+  do i = 1, 10
+     res = res + 1
+  end do
+  !$omp end taskloop
+end subroutine omp_taskloop
+
diff --git a/flang/test/Lower/OpenMP/Todo/taskwait-depend.f90 b/flang/test/Lower/OpenMP/Todo/taskwait-depend.f90
new file mode 100644
index 0000000000000..d1f953be8802f
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/taskwait-depend.f90
@@ -0,0 +1,10 @@
+! RUN: %not_todo_cmd bbc -emit-fir -fopenmp -o - %s -fopenmp-version=50 2>&1 | FileCheck %s
+! RUN: %not_todo_cmd %flang_fc1 -emit-fir -fopenmp -o - %s -fopenmp-version=50 2>&1 | FileCheck %s
+
+! CHECK: not yet implemented: Unhandled clause DEPEND in TASKWAIT construct
+subroutine omp_tw_depend
+  integer :: res
+  !$omp taskwait depend(out: res)
+  res = res + 1
+end subroutine omp_tw_depend
+
diff --git a/flang/test/Lower/OpenMP/Todo/taskwait-nowait.f90 b/flang/test/Lower/OpenMP/Todo/taskwait-nowait.f90
new file mode 100644
index 0000000000000..21e8609b08ba3
--- /dev/null
+++ b/flang/test/Lower/OpenMP/Todo/taskwait-nowait.f90
@@ -0,0 +1,8 @@
+! RUN: %not_todo_cmd bbc -emit-fir -fopenmp -o - %s -fopenmp-version=51 2>&1 | FileCheck %s
+! RUN: %not_todo_cmd %flang_fc1 -emit-fir -fopenmp -o - %s -fopenmp-version=51 2>&1 | FileCheck %s
+
+! CHECK: not yet implemented: Unhandled clause NOWAIT in TASKWAIT construct
+subroutine omp_tw_nowait
+  !$omp taskwait nowait
+end subroutine omp_tw_nowait
+