Specialize to ffid for non-monomorphic builtins.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/lj_record.c b/src/lj_record.c
index 9a3e3375..dbc096a2 100644
--- a/src/lj_record.c
+++ b/src/lj_record.c
@@ -648,7 +648,10 @@ static TRef rec_call_specialize(jit_State *J, GCfunc *fn, TRef tr)
     case FF_coroutine_wrap_aux:
     case FF_string_gmatch_aux:
       /* NYI: io_file_iter doesn't have an ffid, yet. */
-      /* NYI: specialize to ffid? Not strictly necessary, trace will stop. */
+      {  /* Specialize to the ffid. */
+        TRef trid = emitir(IRT(IR_FLOAD, IRT_U8), tr, IRFL_FUNC_FFID);
+        emitir(IRTG(IR_EQ, IRT_INT), trid, lj_ir_kint(J, fn->c.ffid));
+      }
       return tr;
     default:
       /* NYI: don't specialize to non-monomorphic C functions. */