diff --git a/src/share/vm/gc_implementation/g1/g1CardCounts.cpp b/src/share/vm/gc_implementation/g1/g1CardCounts.cpp
index f75e518facce9c08eabfc1fe63a48b2596f0f99d..31972bf3c4e4691d56c6c294a5abce8321c687bf 100644
--- a/src/share/vm/gc_implementation/g1/g1CardCounts.cpp
+++ b/src/share/vm/gc_implementation/g1/g1CardCounts.cpp
@@ -33,8 +33,8 @@
 
 void G1CardCounts::clear_range(size_t from_card_num, size_t to_card_num) {
   if (has_count_table()) {
-    check_card_num(from_card_num,
-                   err_msg("from card num out of range: "SIZE_FORMAT, from_card_num));
+    assert(from_card_num >= 0 && from_card_num < _committed_max_card_num,
+           err_msg("from card num out of range: "SIZE_FORMAT, from_card_num));
     assert(from_card_num < to_card_num,
            err_msg("Wrong order? from: " SIZE_FORMAT ", to: "SIZE_FORMAT,
                    from_card_num, to_card_num));
diff --git a/src/share/vm/gc_implementation/g1/g1CardCounts.hpp b/src/share/vm/gc_implementation/g1/g1CardCounts.hpp
index fd516c0b90ed5a45d5b697861f90dfdb7d931044..129b3b0d2328a901c2a3cbc4991a9aa52dfc951c 100644
--- a/src/share/vm/gc_implementation/g1/g1CardCounts.hpp
+++ b/src/share/vm/gc_implementation/g1/g1CardCounts.hpp
@@ -72,25 +72,21 @@ class G1CardCounts: public CHeapObj<mtGC> {
     return has_reserved_count_table() && _committed_max_card_num > 0;
   }
 
-  void check_card_num(size_t card_num, const char* msg) {
-    assert(card_num >= 0 && card_num < _committed_max_card_num, msg);
-  }
-
   size_t ptr_2_card_num(const jbyte* card_ptr) {
     assert(card_ptr >= _ct_bot,
-           err_msg("Inavalied card pointer: "
+           err_msg("Invalid card pointer: "
                    "card_ptr: " PTR_FORMAT ", "
                    "_ct_bot: " PTR_FORMAT,
                    card_ptr, _ct_bot));
     size_t card_num = pointer_delta(card_ptr, _ct_bot, sizeof(jbyte));
-    check_card_num(card_num,
-                   err_msg("card pointer out of range: " PTR_FORMAT, card_ptr));
+    assert(card_num >= 0 && card_num < _committed_max_card_num,
+           err_msg("card pointer out of range: " PTR_FORMAT, card_ptr));
     return card_num;
   }
 
   jbyte* card_num_2_ptr(size_t card_num) {
-    check_card_num(card_num,
-                   err_msg("card num out of range: "SIZE_FORMAT, card_num));
+    assert(card_num >= 0 && card_num < _committed_max_card_num,
+           err_msg("card num out of range: "SIZE_FORMAT, card_num));
     return (jbyte*) (_ct_bot + card_num);
   }