diff --git a/src/build_file.py b/src/build_file.py
index b3aad23..3ed6c2e 100644
--- a/src/build_file.py
+++ b/src/build_file.py
@@ -476,7 +476,7 @@ def run(d_module, ninja):
     l_irp_sup_o = ["irp_touches.irp.o"]
     l_irp_sup_s = ["irp_touches.irp.F90"]
 
-    if command_line.do_assert:
+    if command_line.do_debug:
         l_irp_sup_o += ["irp_stack.irp.o"]
         l_irp_sup_s += ["irp_stack.irp.F90"]
 
diff --git a/src/entity.py b/src/entity.py
index 5b9f3aa..8717a79 100644
--- a/src/entity.py
+++ b/src/entity.py
@@ -600,7 +600,7 @@ class Entity(object):
         ]
         if command_line.do_openmp:
             result.append(" call irp_lock_%s(.True.)" % (same_as))
-        if command_line.do_assert or command_line.do_debug:
+        if command_line.do_debug:
             result.append("  call irp_enter(irp_here)")
         result += build_call_provide(self.to_provide, self.d_entity)
         result += flatten(map(build_alloc, [self.same_as] + self.others_entity_name))
@@ -609,7 +609,7 @@ class Entity(object):
             "  %s_is_built = .True." % (same_as), ""
         ]
         result += [" endif"]
-        if command_line.do_assert or command_line.do_debug:
+        if command_line.do_debug:
             result.append("  call irp_leave(irp_here)")
         if command_line.do_openmp:
             result.append(" call irp_lock_%s(.False.)" % (same_as))
diff --git a/src/irp_stack.py b/src/irp_stack.py
index f168176..a86bda5 100644
--- a/src/irp_stack.py
+++ b/src/irp_stack.py
@@ -159,7 +159,7 @@ end subroutine
 """
 
   # $1
-  if do_assert or do_debug:
+  if do_debug:
     s = """
  if (.not.alloc) then
  """
@@ -168,6 +168,9 @@ end subroutine
  !$OMP PARALLEL
  !$OMP SINGLE
  nthread = omp_get_num_threads()
+ if (nthread>1) then
+   stop 'irpf90 -debug does not work in multithread'
+ endif
  !$OMP END SINGLE
  !$OMP END PARALLEL
  !$OMP CRITICAL
@@ -223,7 +226,7 @@ end subroutine
     txt = txt.replace("$3","")
 
   # $4
-  if do_debug or do_assert:
+  if do_debug:
     txt = txt.replace("$4","""
   stack_index(ithread) = max(0,stack_index(ithread)-1)""")
   else:
diff --git a/src/preprocessed_text.py b/src/preprocessed_text.py
index 7aa75bf..1dae2f7 100644
--- a/src/preprocessed_text.py
+++ b/src/preprocessed_text.py
@@ -544,7 +544,7 @@ def irp_simple_statements(text):
 
     def process_return(line):
         assert type(line) == Return
-        if command_line.do_assert or command_line.do_debug:
+        if command_line.do_debug:
             newline = Simple_line(line.i, " call irp_leave(irp_here)", line.filename)
             result = [newline, line]
         else:
@@ -585,7 +585,6 @@ def irp_simple_statements(text):
                 Empty_line(i, "!", f),
                 Empty_line(i, "! >>> %s" % (txt, ), f),
                 If(i, "  if (.not.%s) then" % (condition, ), f),
-                Simple_line(i, "   call irp_trace", f),
                 Simple_line(i, "   print *, irp_here//': Assert failed:'", f),
                 Simple_line(i, "   print *, ' file: %s, line: %d'" % (f, i), f),
                 Simple_line(i, "   print *, '%s'" % (condition_str, ), f),
@@ -600,7 +599,7 @@ def irp_simple_statements(text):
     def process_end(line):
         '''Add irp_leave if necessary'''
 
-        if command_line.do_assert or command_line.do_debug:
+        if command_line.do_debug:
             i = line.i
             f = line.filename
             result = [Simple_line(i, " call irp_leave(irp_here)", f), line]
@@ -624,7 +623,7 @@ def irp_simple_statements(text):
             Begin_provider(i, line.text, (f, varname)),
             Declaration(i, "  character*(%d) :: irp_here = '%s'" % (length, varname), f)
         ]
-        if command_line.do_assert or command_line.do_debug:
+        if command_line.do_debug:
             result += [Simple_line(i, "  call irp_enter(irp_here)", f), ]
         return result
 
@@ -646,7 +645,7 @@ def irp_simple_statements(text):
         f = line.filename
         result = [ line, Declaration(i, "  character*(%d) :: irp_here = '%s'" % (length, subname), f)]
 
-        if command_line.do_assert or command_line.do_debug:
+        if command_line.do_debug:
             result += [Simple_line(i, "  call irp_enter_f(irp_here)", f), ]
         return result
 
@@ -659,7 +658,7 @@ def irp_simple_statements(text):
         result = [
             line, Declaration(i, "  character*(%d) :: irp_here = '%s'" % (length, subname), f)
         ]
-        if command_line.do_assert or command_line.do_debug:
+        if command_line.do_debug:
             result += [Simple_line(i, "  call irp_enter_f(irp_here)", f), ]
         return result