diff --git a/bin/irpf90 b/bin/irpf90
index 773b5d8..7112473 100755
--- a/bin/irpf90
+++ b/bin/irpf90
@@ -32,5 +32,11 @@ wd = os.path.abspath(os.path.dirname(__file__))
 sys.path.insert(0,(wd+"/../src/"))
 sys.path.insert(0,(wd+"/../share/irpf90/src/"))
 
-import irpf90
-irpf90.main()
+debug = int(os.getenv("IRP_DEBUG",0))
+if debug == 0:
+  import irpf90
+  irpf90.main()
+else:
+  import profile
+  print "Profiling irpf90"
+  profile.run('import irpf90 ; irpf90.main()')
diff --git a/src/irp_stack.py b/src/irp_stack.py
index 74550ee..1046e47 100644
--- a/src/irp_stack.py
+++ b/src/irp_stack.py
@@ -54,9 +54,11 @@ subroutine irp_enter(irp_where)
  integer       :: nthread
  character*(*) :: irp_where
 $OMP_DECL
+!$OMP CRITICAL
  ithread = $OMP_GET_THREAD_NUM
  nthread = $OMP_GET_NUM_THREADS
 $1
+!$OMP END CRITICAL
 """
   if command_line.do_memory:
       txt+="""
@@ -75,9 +77,11 @@ subroutine irp_leave (irp_where)
   integer       :: ithread
   double precision :: cpu
 $OMP_DECL
+!$OMP CRITICAL
   ithread = $OMP_GET_THREAD_NUM
 $3
 $4
+!$OMP END CRITICAL
 end subroutine
 """
 
@@ -97,14 +101,12 @@ end subroutine
   # $1
   if do_assert or do_debug:
     txt = txt.replace("$1","""
-!$OMP CRITICAL
  if (.not.alloc) then
-   allocate(irp_stack(STACKMAX,nthread))
-   allocate(irp_cpu(STACKMAX,nthread))
-   allocate(stack_index(nthread))
+   allocate(irp_stack(STACKMAX,nthread+1))
+   allocate(irp_cpu(STACKMAX,nthread+1))
+   allocate(stack_index(nthread+1))
    alloc = .True.
  endif
-!$OMP END CRITICAL
  stack_index(ithread+1) = stack_index(ithread+1)+1
  irp_stack(stack_index(ithread+1),ithread+1) = irp_where""")
     if command_line.do_memory:
diff --git a/src/irpf90.py b/src/irpf90.py
index ee6e948..6484226 100644
--- a/src/irpf90.py
+++ b/src/irpf90.py
@@ -24,6 +24,8 @@
 #   31062 Toulouse Cedex 4      
 #   scemama@irsamc.ups-tlse.fr
 
+import sys
+sys.setcheckinterval(1000)
 
 def main():
   from command_line import command_line
diff --git a/src/irpf90_t.py b/src/irpf90_t.py
index ef41966..d422f58 100644
--- a/src/irpf90_t.py
+++ b/src/irpf90_t.py
@@ -33,6 +33,7 @@ class Line(object):
   def __init__(self,i,text,filename):
     self.i = i
     self.text = text
+    self.lower = text.lower()
     self.filename = filename
     self._lower = None
 
diff --git a/src/makefile.py b/src/makefile.py
index e0acd9c..2819e9b 100644
--- a/src/makefile.py
+++ b/src/makefile.py
@@ -152,4 +152,3 @@ def run():
 
     file.close()
     sys.exit(0)
-
diff --git a/src/parsed_text.py b/src/parsed_text.py
index 1738df1..c2e17aa 100644
--- a/src/parsed_text.py
+++ b/src/parsed_text.py
@@ -38,29 +38,32 @@ stuple = map(lambda s: (s, subroutines[s].regexp), subroutines.keys())
 stuple = filter(lambda s: subroutines[s[0]].is_function, stuple)
 re_string_sub = regexps.re_string.sub
 
+regexps_re_string_sub = regexps.re_string.sub
 def find_variables_in_line(line):
   assert isinstance(line,Line)
   result = []
   sub_done = False
   buffer = line.text_lower
+  ap = result.append
   for v,same_as,regexp in vtuple:
     if v in buffer:
       if not sub_done:
-        buffer = re_string_sub('',buffer)
+        buffer = regexps_re_string_sub('',buffer)
         sub_done = True
       if regexp.search(buffer) is not None:
-        result.append(same_as)
+        ap(same_as)
   return result
 
 def find_funcs_in_line(line):
   assert isinstance(line,Line)
   result = []
+  append = result.append
   sub_done = False
   buffer = line.text_lower
   for s,regexp in stuple:
      if s in buffer:
       if regexp.search(buffer) is not None:
-        result.append(s)
+        append(s)
   return result
 
 
@@ -90,6 +93,7 @@ def get_parsed_text():
   def func(filename, text):
     varlist = []
     result = []
+    append = result.append
     for line in filter(
       lambda x: type(x) not in [ Doc, Begin_doc, End_doc ],
       text):
@@ -110,28 +114,28 @@ def get_parsed_text():
         Function,
         End,
       ]: 
-        result.append( ([],line) )
+        append( ([],line) )
       elif isinstance(line,End_provider):
         varlist = []
-        result.append( ([],line) )
+        append( ([],line) )
       elif isinstance(line,Provide):
         l = line.text_lower.split()[1:]
         l = filter(lambda x: x not in varlist, l)
         for v in l:
           if v not in variables.keys():
             error.fail(line,"Variable %s is unknown"%(v))
-        result.append( (l,Simple_line(line.i,"!%s"%(line.text),line.filename)) )
+        append( (l,Simple_line(line.i,"!%s"%(line.text),line.filename)) )
       elif isinstance(line,Call):
         l = find_variables_in_line(line)
         l = filter(lambda x: x not in varlist, l)
         sub = find_subroutine_in_line(line)
         if sub not in subroutines:
           t = Simple_line
-          result.append( (l,Simple_line(line.i,line.text,line.filename)) )
+          append( (l,Simple_line(line.i,line.text,line.filename)) )
         else:
-          result.append( (l,line) )
+          append( (l,line) )
           if subroutines[sub].touches != []:
-            result.append( ([],Provide_all(line.i,"",line.filename)) )
+            append( ([],Provide_all(line.i,"",line.filename)) )
       elif isinstance(line,Free):
         vars = line.text_lower.split()
         if len(vars) < 2:
@@ -139,7 +143,7 @@ def get_parsed_text():
         vars = vars[1:]
         for v in vars:
           variables[v].is_freed = True
-        result.append( ([],Simple_line(line.i,"!%s"%(line.text),line.filename)) )
+        append( ([],Simple_line(line.i,"!%s"%(line.text),line.filename)) )
         use = map(lambda x: "  use %s"%(variables[x].fmodule),vars)
         for var in vars:
           result += map(lambda x: ([],Use(line.i,x,line.filename)),
@@ -148,10 +152,10 @@ def get_parsed_text():
             variables[var].free)
       elif isinstance(line,Irp_read):
         variables[line.filename]._is_read = True
-        result.append( ([],Simple_line(line.i,"!%s"%(line.text),line.filename)) )
+        append( ([],Simple_line(line.i,"!%s"%(line.text),line.filename)) )
       elif isinstance(line,Irp_write):
         variables[line.filename]._is_written = True
-        result.append( ([],Simple_line(line.i,"!%s"%(line.text),line.filename)) )
+        append( ([],Simple_line(line.i,"!%s"%(line.text),line.filename)) )
       elif isinstance(line,Touch):
         vars = line.text_lower.split()
         if len(vars) < 2:
@@ -197,7 +201,7 @@ def get_parsed_text():
         except ValueError:
           print v, variables[v].same_as
           raise
-        result.append( (variable_list,line) )
+        append( (variable_list,line) )
       else:
         l = find_variables_in_line(line)
         l = filter(lambda x: x not in varlist, l)
@@ -210,7 +214,6 @@ def get_parsed_text():
  #return main_result
   return parallel_loop(func,preprocessed_text)
   
-
 parsed_text = get_parsed_text()
 
 
@@ -252,6 +255,7 @@ def move_variables():
 
   def func(filename, text):
     result = []
+    append = result.append
     # 1st pass
     varlist = []
     ifvars = []
@@ -264,20 +268,20 @@ def move_variables():
     for vars,line in revtext:
       if type(line) in [ End_provider,End ]:
         varlist = []
-        result.append( ([],line) )
+        append( ([],line) )
       elif type(line) in [ Endif, End_select ]:
         old_ifvars.append( list(ifvars) )
         old_elsevars.append( list(elsevars) )
         old_varlist.append( list(varlist) )
         varlist = []
-        result.append( ([],line) )
+        append( ([],line) )
       elif type(line) == Else:
         elsevars += list(varlist)
-        result.append( (varlist,line) )
+        append( (varlist,line) )
         varlist = []
       elif type(line) in [ Elseif, Case ]:
         ifvars += list(varlist)
-        result.append( (varlist,line) )
+        append( (varlist,line) )
         if vars != []:
           varlist = old_varlist.pop()
           varlist += vars
@@ -285,29 +289,30 @@ def move_variables():
         varlist = []
       elif type(line) in [ If, Select ]:
         ifvars += list(varlist)
-        result.append( (varlist,line) )
+        append( (varlist,line) )
         vars += filter(lambda x: x in elsevars, ifvars)
         ifvars = old_ifvars.pop()
         elsevars = old_elsevars.pop()
         varlist = old_varlist.pop() + vars
       elif type(line) in [ Begin_provider, Subroutine, Function ]:
         varlist += vars
-        result.append( (varlist,line) )
+        append( (varlist,line) )
         if old_varlist != [] \
          or old_ifvars != [] \
          or old_elsevars != []:
           error.fail(line,"End if missing")
         varlist = []
       elif isinstance(line,Provide_all):
-        result.append( (vars,line) )
+        append( (vars,line) )
       else:
         varlist += vars
-        result.append( ([],line) )
+        append( ([],line) )
     result.reverse()
   
     # 2nd pass
     text = result
     result = []
+    append = result.append
     old_varlist = []
     varlist = []
     for vars,line in text:
@@ -368,11 +373,12 @@ def add_subroutine_needs():
   main_result = []
   for filename, text in parsed_text:
     result = []
+    append = result.append
     for vars,line in text:
       if isinstance(line,Call):
         subname = find_subname(line)
         vars = subroutines[subname].to_provide
-      result.append( (vars,line) )
+      append( (vars,line) )
     main_result.append( (filename, result) )
   return main_result
   
diff --git a/src/preprocessed_text.py b/src/preprocessed_text.py
index 51816bd..ef20570 100644
--- a/src/preprocessed_text.py
+++ b/src/preprocessed_text.py
@@ -538,12 +538,12 @@ def irp_simple_statements(text):
 
   def process_begin_provider(line):
     assert isinstance(line,Begin_provider)
-    buffer = line.text.replace('['," ")
+    buffer = line.lower.replace('['," ")
     buffer = buffer.replace(']',"")
     buffer = buffer.split(',')
     if len(buffer) < 2:
       error.fail(line,"Error in Begin_provider statement")
-    varname = buffer[1].strip().lower()
+    varname = buffer[1].strip()
     length = len(varname)
     i = line.i
     f = line.filename
@@ -557,12 +557,12 @@ def irp_simple_statements(text):
 
   def process_cont_provider(line):
     assert isinstance(line,Cont_provider)
-    buffer = line.text.replace('['," ")
+    buffer = line.lower.replace('['," ")
     buffer = buffer.replace(']',"")
     buffer = buffer.split(',')
     if len(buffer) < 2:
       error.fail(line,"Error in Cont_provider statement")
-    varname = buffer[1].strip().lower()
+    varname = buffer[1].strip()
     i = line.i
     f = line.filename
     return [ Cont_provider(i,line.text,(f,varname)) ]
@@ -599,7 +599,7 @@ def irp_simple_statements(text):
 
   def process_program(line):
     assert isinstance(line,Program)
-    program_name = line.text.split()[1].lower()
+    program_name = line.lower.split()[1]
     result = [ Program(0,"",program_name) ] + \
        process_subroutine( Subroutine(line.i,"subroutine %s"%(program_name,),line.filename) )
     return result
@@ -691,7 +691,7 @@ endif'''
   result = []
   for line in text:
     if isinstance(line,If):
-      if line.text.lower().endswith("then"):
+      if line.lower.endswith("then"):
         result.append(line)
       else:
         buffer = line.text
diff --git a/src/subroutine.py b/src/subroutine.py
index e17b085..e555173 100644
--- a/src/subroutine.py
+++ b/src/subroutine.py
@@ -49,7 +49,7 @@ class Sub(object):
   ############################################################
   def is_function(self):
     if '_is_function' not in self.__dict__:
-      self._is_function = "function" in self.line.text.lower()
+      self._is_function = "function" in self.line.lower
     return self._is_function
   is_function = property(is_function)
 
diff --git a/src/variable.py b/src/variable.py
index e3bbd58..4762ca1 100644
--- a/src/variable.py
+++ b/src/variable.py
@@ -121,10 +121,11 @@ class Variable(object):
   def others(self):
     if '_others' not in self.__dict__:
       result = []
+      append = result.append
       f = lambda  l: type(l) in [Begin_provider, Cont_provider]
       lines = filter(f, self.text)
       for line in lines:
-        result.append(line.filename[1])
+        append(line.filename[1])
       result.remove(self.name)
       self._others = result
     return self._others
diff --git a/src/variables.py b/src/variables.py
index dd48d4d..0b10bed 100644
--- a/src/variables.py
+++ b/src/variables.py
@@ -66,13 +66,14 @@ def call_provides(vars,opt=False):
     all_children = flatten( map(lambda x: variables[x].children, vars ))
     vars = filter(lambda x: x not in all_children,vars)
   def fun(x):
+    result = []
     if command_line.do_openmp:
-      result  = [ "!$OMP TASK" ]
-    else:
-      result = []
+      result  += [ "!$OMP TASK" ]
+    result += [ \
+    "  if (.not.%s_is_built) then"%(x) ]
+    result += [ \
+    "    call provide_%s"%(x) ]
     result += [ \
-    "  if (.not.%s_is_built) then"%(x),
-    "    call provide_%s"%(x),
     "  endif" ]
     if command_line.do_openmp:
       result += [ "!$OMP END TASK" ]
diff --git a/src/version.py b/src/version.py
index 3be16b6..29e3edb 100644
--- a/src/version.py
+++ b/src/version.py
@@ -1 +1 @@
-version = "1.1.50"
+version = "1.1.51"