diff --git a/src/lj_opt_sink.c b/src/lj_opt_sink.c
index 975ee831..c5e9a95a 100644
--- a/src/lj_opt_sink.c
+++ b/src/lj_opt_sink.c
@@ -166,8 +166,8 @@ static void sink_remark_phi(jit_State *J)
 /* Sweep instructions and tag sunken allocations and stores. */
 static void sink_sweep_ins(jit_State *J)
 {
-  IRIns *ir, *irfirst = IR(J->cur.nk);
-  for (ir = IR(J->cur.nins-1) ; ir >= irfirst; ir--) {
+  IRIns *ir, *irbase = IR(REF_BASE);
+  for (ir = IR(J->cur.nins-1) ; ir >= irbase; ir--) {
     switch (ir->o) {
     case IR_ASTORE: case IR_HSTORE: case IR_FSTORE: case IR_XSTORE: {
       IRIns *ira = sink_checkalloc(J, ir);
@@ -217,6 +217,10 @@ static void sink_sweep_ins(jit_State *J)
       break;
     }
   }
+  for (ir = IR(J->cur.nk); ir < irbase; ++ir) {
+    irt_clearmark(ir->t);
+    ir->prev = REGSP_INIT;
+  }
 }
 
 /* Allocation sinking and store sinking.