diff --git a/opal/class/opal_pointer_array.c b/opal/class/opal_pointer_array.c
index 9b2da8be58..b28337a616 100644
--- a/opal/class/opal_pointer_array.c
+++ b/opal/class/opal_pointer_array.c
@@ -87,6 +87,10 @@ static void opal_pointer_array_destruct(opal_pointer_array_t *array)
  * A classical find first zero bit (ffs) on a large array. It checks starting
  * from the indicated position until it finds a zero bit. If SET is true,
  * the bit is set. The position of the bit is returned in store.
+ *
+ * According to Section 6.4.4.1 of the C standard we don't need to prepend a type
+ * indicator to constants (the type is inferred by the compiler according to
+ * the number of bits necessary to represent it).
  */
 #define FIND_FIRST_ZERO(START_IDX, STORE)                               \
     do {                                                                \
@@ -96,27 +100,27 @@ static void opal_pointer_array_destruct(opal_pointer_array_t *array)
             break;                                                      \
         }                                                               \
         GET_BIT_POS((START_IDX), __b_idx, __b_pos);                     \
-        for (; table->free_bits[__b_idx] == 0xFFFFFFFFFFFFFFFFULL; __b_idx++); \
+        for (; table->free_bits[__b_idx] == 0xFFFFFFFFFFFFFFFFu; __b_idx++); \
         assert(__b_idx < (uint32_t)table->size);                        \
         uint64_t __check_value = table->free_bits[__b_idx];             \
         __b_pos = 0;                                                    \
                                                                         \
-        if( 0x00000000FFFFFFFFULL == (__check_value & 0x00000000FFFFFFFFULL) ) { \
+        if( 0x00000000FFFFFFFFu == (__check_value & 0x00000000FFFFFFFFu) ) { \
             __check_value >>= 32; __b_pos += 32;                        \
         }                                                               \
-        if( 0x000000000000FFFFULL == (__check_value & 0x000000000000FFFFULL) ) { \
+        if( 0x000000000000FFFFu == (__check_value & 0x000000000000FFFFu) ) { \
             __check_value >>= 16; __b_pos += 16;                        \
         }                                                               \
-        if( 0x00000000000000FFULL == (__check_value & 0x00000000000000FFULL) ) { \
+        if( 0x00000000000000FFu == (__check_value & 0x00000000000000FFu) ) { \
             __check_value >>= 8; __b_pos += 8;                          \
         }                                                               \
-        if( 0x000000000000000FULL == (__check_value & 0x000000000000000FULL) ) { \
+        if( 0x000000000000000Fu == (__check_value & 0x000000000000000Fu) ) { \
             __check_value >>= 4; __b_pos += 4;                          \
         }                                                               \
-        if( 0x0000000000000003ULL == (__check_value & 0x0000000000000003ULL) ) { \
+        if( 0x0000000000000003u == (__check_value & 0x0000000000000003u) ) { \
             __check_value >>= 2; __b_pos += 2;                          \
         }                                                               \
-        if( 0x0000000000000001ULL == (__check_value & 0x0000000000000001ULL) ) { \
+        if( 0x0000000000000001u == (__check_value & 0x0000000000000001u) ) { \
             __b_pos += 1;                                               \
         }                                                               \
         (STORE) = (__b_idx * 8 * sizeof(uint64_t)) + __b_pos;           \
@@ -129,8 +133,8 @@ static void opal_pointer_array_destruct(opal_pointer_array_t *array)
     do {                                                                \
         uint32_t __b_idx, __b_pos;                                      \
         GET_BIT_POS((IDX), __b_idx, __b_pos);                           \
-        assert( 0 == (table->free_bits[__b_idx] & (1UL << __b_pos)));   \
-        table->free_bits[__b_idx] |= (1ULL << __b_pos);                 \
+        assert( 0 == (table->free_bits[__b_idx] & (((uint64_t)1) << __b_pos))); \
+        table->free_bits[__b_idx] |= (((uint64_t)1) << __b_pos);        \
     } while(0)
 
 /**
@@ -140,8 +144,8 @@ static void opal_pointer_array_destruct(opal_pointer_array_t *array)
     do {                                                                \
         uint32_t __b_idx, __b_pos;                                      \
         GET_BIT_POS((IDX), __b_idx, __b_pos);                           \
-        assert( (table->free_bits[__b_idx] & (1UL << __b_pos)));        \
-        table->free_bits[__b_idx] ^= (1ULL << __b_pos);                 \
+        assert( (table->free_bits[__b_idx] & (((uint64_t)1) << __b_pos))); \
+        table->free_bits[__b_idx] ^= (((uint64_t)1) << __b_pos);        \
     } while(0)
 
 #if 0
@@ -159,9 +163,9 @@ static void opal_pointer_array_validate(opal_pointer_array_t *array)
         GET_BIT_POS(i, b_idx, p_idx);
         if( NULL == array->addr[i] ) {
             cnt++;
-            assert( 0 == (array->free_bits[b_idx] & (1ULL << p_idx)) );
+            assert( 0 == (array->free_bits[b_idx] & (((uint64_t)1) << p_idx)) );
         } else {
-            assert( 0 != (array->free_bits[b_idx] & (1ULL << p_idx)) );
+            assert( 0 != (array->free_bits[b_idx] & (((uint64_t)1) << p_idx)) );
         }
     }
     assert(cnt == array->number_free);