diff --git a/src/util/mpn.h b/src/util/mpn.h
index 621f728e0..d9c71c24b 100644
--- a/src/util/mpn.h
+++ b/src/util/mpn.h
@@ -27,14 +27,6 @@ Revision History:
 typedef unsigned int mpn_digit;
 
 class mpn_manager {
-#ifndef SINGLE_THREAD
-    std::recursive_mutex m_lock;
-#define MPN_BEGIN_CRITICAL() m_lock.lock()
-#define MPN_END_CRITICAL() m_lock.unlock()
-#else
-#define MPN_BEGIN_CRITICAL() {}
-#define MPN_END_CRITICAL()   {}
-#endif
 
 public:
     mpn_manager();
diff --git a/src/util/mpz.cpp b/src/util/mpz.cpp
index a66add988..4d93ea24d 100644
--- a/src/util/mpz.cpp
+++ b/src/util/mpz.cpp
@@ -187,15 +187,16 @@ mpz_manager<SYNCH>::~mpz_manager() {
 template<bool SYNCH>
 mpz_cell * mpz_manager<SYNCH>::allocate(unsigned capacity) {
     SASSERT(capacity >= m_init_cell_capacity);
+    mpz_cell * cell;
 #ifdef SINGLE_THREAD
-    mpz_cell * cell = reinterpret_cast<mpz_cell*>(m_allocator.allocate(cell_size(capacity)));
+    cell = reinterpret_cast<mpz_cell*>(m_allocator.allocate(cell_size(capacity)));
 #else
-#if SYNC
-    mpz_cell * cell = reinterpret_cast<mpz_cell*>(m_allocator.allocate(cell_size(capacity)));
-#else
-    mpz_cell * cell = reinterpret_cast<mpz_cell*>(memory::allocate(cell_size(capacity)));
-    
-#endif
+    if (SYNCH) {
+        cell = reinterpret_cast<mpz_cell*>(memory::allocate(cell_size(capacity)));
+    }
+    else {
+        cell = reinterpret_cast<mpz_cell*>(m_allocator.allocate(cell_size(capacity)));
+    }
 #endif
     cell->m_capacity = capacity;
     return cell;
@@ -207,11 +208,12 @@ void mpz_manager<SYNCH>::deallocate(bool is_heap, mpz_cell * ptr) {
 #ifdef SINGLE_THREAD
         m_allocator.deallocate(cell_size(ptr->m_capacity), ptr); 
 #else
-#if SYNC
-        m_allocator.deallocate(cell_size(ptr->m_capacity), ptr);        
-#else
-        memory::deallocate(ptr);
-#endif
+        if (SYNCH) {
+            memory::deallocate(ptr);
+        }
+        else {
+            m_allocator.deallocate(cell_size(ptr->m_capacity), ptr);        
+        }
 #endif
     }
 }
diff --git a/src/util/mpz.h b/src/util/mpz.h
index 530bebba7..87a9f0b5b 100644
--- a/src/util/mpz.h
+++ b/src/util/mpz.h
@@ -196,14 +196,16 @@ class mpz_manager {
     mutable mpz_t     m_int64_min;
 
     mpz_t * allocate() {        
+        mpz_t * cell;
 #ifdef SINGLE_THREAD
-        mpz_t * cell = reinterpret_cast<mpz_t*>(m_allocator.allocate(sizeof(mpz_t)));        
+        cell = reinterpret_cast<mpz_t*>(m_allocator.allocate(sizeof(mpz_t)));        
 #else
-#if SYNC
-        mpz_t * cell = reinterpret_cast<mpz_t*>(m_allocator.allocate(sizeof(mpz_t)));        
-#else
-        mpz_t * cell = reinterpret_cast<mpz_t*>(memory::allocate(sizeof(mpz_t)));
-#endif
+        if (SYNCH) {
+            cell = reinterpret_cast<mpz_t*>(memory::allocate(sizeof(mpz_t)));
+        }
+        else {
+            cell = reinterpret_cast<mpz_t*>(m_allocator.allocate(sizeof(mpz_t)));        
+        }
 #endif
         mpz_init(*cell);
         return cell;
@@ -215,11 +217,12 @@ class mpz_manager {
 #ifdef SINGLE_THREAD
             m_allocator.deallocate(sizeof(mpz_t), ptr); 
 #else
-#if SYNC
-            memory::deallocate(ptr);
-#else
-            m_allocator.deallocate(sizeof(mpz_t), ptr); 
-#endif
+            if (SYNCH) {
+                memory::deallocate(ptr);
+            }
+            else {
+                m_allocator.deallocate(sizeof(mpz_t), ptr); 
+            }
 #endif
         }
     }