diff --git a/rjit_c.c b/rjit_c.c
index dc489257a8..e6d8d5da5c 100644
--- a/rjit_c.c
+++ b/rjit_c.c
@@ -535,7 +535,7 @@ extern VALUE rb_vm_set_ivar_id(VALUE obj, ID id, VALUE val);
 extern VALUE rb_ary_unshift_m(int argc, VALUE *argv, VALUE ary);
 extern void* rb_rjit_entry_stub_hit(VALUE branch_stub);
 extern void* rb_rjit_branch_stub_hit(VALUE branch_stub, int sp_offset, int target0_p);
-extern size_t rb_vm_insns_count;
+extern uint64_t rb_vm_insns_count;
 
 #include "rjit_c.rbinc"