diff --git a/src/lj_carith.c b/src/lj_carith.c
index 418400cf..e3287de9 100644
--- a/src/lj_carith.c
+++ b/src/lj_carith.c
@@ -118,7 +118,7 @@ static int carith_ptr(lua_State *L, CTState *cts, CDArith *ca, MMS mm)
 	/* All valid pointer differences on x64 are in (-2^47, +2^47),
 	** which fits into a double without loss of precision.
 	*/
-	setintptrV(L->top-1, (int32_t)diff);
+	setintptrV(L->top-1, diff);
 	return 1;
       } else if (mm == MM_lt) {  /* Pointer comparison (unsigned). */
 	setboolV(L->top-1, ((uintptr_t)pp < (uintptr_t)pp2));