diff --git a/src/mpi/errhan/errutil.c b/src/mpi/errhan/errutil.c
index 22abb4c7a0c..4d5167b8816 100644
--- a/src/mpi/errhan/errutil.c
+++ b/src/mpi/errhan/errutil.c
@@ -102,6 +102,11 @@
  * their sizes, and masks and shifts that may be used to extract them.
  */
 
+/* whether an errcode is a generic error class */
+#define is_valid_error_class(errcode) \
+    ((errcode >= 0 && errcode <= MPICH_ERR_LAST_CLASS) || \
+     (errcode > MPICH_ERR_FIRST_MPIX && errcode <= MPICH_ERR_LAST_MPIX))
+
 static int did_err_init = FALSE;        /* helps us solve a bootstrapping problem */
 
 /* A few prototypes.  These routines are called from the MPIR_Err_return
@@ -686,7 +691,7 @@ static void CombineSpecificCodes(int error1_code, int error2_code, int error2_cl
 
 static const char *get_class_msg(int error_class)
 {
-    if (error_class >= 0 && error_class < MPIR_MAX_ERROR_CLASS_INDEX) {
+    if (is_valid_error_class(error_class)) {
         return classToMsg[error_class];
     } else {
         /* --BEGIN ERROR HANDLING-- */
@@ -743,7 +748,7 @@ static void CombineSpecificCodes(int error1_code, int error2_code, int error2_cl
 
 static const char *get_class_msg(int error_class)
 {
-    if (error_class >= 0 && error_class < MPIR_MAX_ERROR_CLASS_INDEX) {
+    if (is_valid_error_class(error_class)) {
         return generic_err_msgs[class_to_index[error_class]].long_name;
     } else {
         /* --BEGIN ERROR HANDLING-- */
@@ -1242,7 +1247,7 @@ static void MPIR_Err_print_stack_string(int errcode, char *str, int maxlen)
 
 static const char *get_class_msg(int error_class)
 {
-    if (error_class >= 0 && error_class < MPIR_MAX_ERROR_CLASS_INDEX) {
+    if (is_valid_error_class(error_class)) {
         return generic_err_msgs[class_to_index[error_class]].long_name;
     } else {
         /* --BEGIN ERROR HANDLING-- */
@@ -1813,8 +1818,9 @@ static int checkErrcodeIsValid(int errcode)
     int ring_id, generic_idx, ring_idx;
 
     /* If the errcode is a class, then it is valid */
-    if (errcode <= MPIR_MAX_ERROR_CLASS_INDEX && errcode >= 0)
+    if (is_valid_error_class(errcode)) {
         return 0;
+    }
 
     if (convertErrcodeToIndexes(errcode, &ring_idx, &ring_id, &generic_idx) != 0) {
         /* --BEGIN ERROR HANDLING-- */