diff --git a/lib/cext/ABI_version.txt b/lib/cext/ABI_version.txt
index 0cfbf08886fc..00750edc07d6 100644
--- a/lib/cext/ABI_version.txt
+++ b/lib/cext/ABI_version.txt
@@ -1 +1 @@
-2
+3
diff --git a/lib/cext/include/ruby/internal/arithmetic/fixnum.h b/lib/cext/include/ruby/internal/arithmetic/fixnum.h
index 852330430ce0..c8927ac82431 100644
--- a/lib/cext/include/ruby/internal/arithmetic/fixnum.h
+++ b/lib/cext/include/ruby/internal/arithmetic/fixnum.h
@@ -40,11 +40,7 @@
  * represent  is   4,611,686,018,427,387,904,  which   is  not   fixable.   The
  * seemingly-strange "< FIXNUM_MAX + 1" expression below is due to this.
  */
-#ifdef TRUFFLERUBY
-#define RB_POSFIXABLE(f) ((f) <= RUBY_FIXNUM_MAX)
-#else
 #define RB_POSFIXABLE(_) ((_) <  RUBY_FIXNUM_MAX + 1)
-#endif
 
 /**
  * Checks if the passed value is in  range of fixnum, assuming it is a negative
@@ -55,15 +51,10 @@
 /** Checks if the passed value is in  range of fixnum */
 #define RB_FIXABLE(_)    (RB_POSFIXABLE(_) && RB_NEGFIXABLE(_))
 
-#ifdef TRUFFLERUBY
-#define RUBY_FIXNUM_MAX LONG_MAX
-#define RUBY_FIXNUM_MIN LONG_MIN
-#else
 /** Maximum possible value that a fixnum can represent. */
 #define RUBY_FIXNUM_MAX  (LONG_MAX / 2)
 
 /** Minimum possible value that a fixnum can represent. */
 #define RUBY_FIXNUM_MIN  (LONG_MIN / 2)
-#endif /* TRUFFLERUBY */
 
 #endif /* RBIMPL_ARITHMETIC_FIXNUM_H */
diff --git a/lib/cext/include/ruby/internal/arithmetic/long.h b/lib/cext/include/ruby/internal/arithmetic/long.h
index 73237bf3b1a8..40cc9714f5f0 100644
--- a/lib/cext/include/ruby/internal/arithmetic/long.h
+++ b/lib/cext/include/ruby/internal/arithmetic/long.h
@@ -120,9 +120,6 @@ RBIMPL_ATTR_ARTIFICIAL()
 static inline VALUE
 RB_INT2FIX(long i)
 {
-#ifdef TRUFFLERUBY
-    return rb_tr_longwrap(i);
-#else
     RBIMPL_ASSERT_OR_ASSUME(RB_FIXABLE(i));
 
     /* :NOTE: VALUE can be wider than long.  As j being unsigned, 2j+1 is fully
@@ -135,7 +132,6 @@ RB_INT2FIX(long i)
 
     RBIMPL_ASSERT_OR_ASSUME(RB_FIXNUM_P(n));
     return n;
-#endif
 }
 
 /**
diff --git a/src/main/c/cext/integer.c b/src/main/c/cext/integer.c
index 51a8427f8336..29b324ece685 100644
--- a/src/main/c/cext/integer.c
+++ b/src/main/c/cext/integer.c
@@ -157,6 +157,6 @@ int rb_absint_singlebit_p(VALUE val) {
 }
 
 VALUE rb_int2big(intptr_t n) {
-  // it cannot overflow Fixnum
-  return LONG2FIX(n);
+  // intptr_t is the same as long
+  return rb_tr_longwrap(n);
 }