gistfile1.txt

diff --git a/src/jit/emit_x64.dasc b/src/jit/emit_x64.dasc
index 8e83090..666e7e8 100644
--- a/src/jit/emit_x64.dasc
+++ b/src/jit/emit_x64.dasc
@@ -929,6 +929,26 @@ void MVM_jit_emit_primitive(MVMThreadContext *tc, MVMJitGraph *jg,
         |2:
         break;
     }
+    case MVM_OP_iscont: {
+        MVMint16 dst = ins->operands[0].reg.orig;
+        MVMint16 src = ins->operands[1].reg.orig;
+        | mov TMP1, WORK[src];
+        | test TMP1, TMP1;
+        // obj is null
+        | jz >1;
+        | mov TMP2, OBJECT:TMP1->st;
+        | mov TMP2, STABLE:TMP2->container_spec;
+        | test TMP2, TMP2;
+        // container spec is zero
+        | jz >1;
+        // we're here: obj is non-null and container_spec is non-null.
+        | mov qword WORK[dst], 1;
+        | jmp >2;
+        |1:
+        | mov qword WORK[dst], 0;
+        |2:
+        break;
+    }
     case MVM_OP_sp_namedarg_used: {
         MVMuint16 param = ins->operands[0].lit_i16;
         | mov TMP1, FRAME->params.named_used;
diff --git a/src/jit/graph.c b/src/jit/graph.c
index c02bb08..5a0864b 100644
--- a/src/jit/graph.c
+++ b/src/jit/graph.c
@@ -674,6 +674,7 @@ static MVMint32 jgb_consume_ins(MVMThreadContext *tc, JitGraphBuilder *jgb,
     case MVM_OP_getcode:
     case MVM_OP_sp_fastcreate:
     case MVM_OP_decont:
+    case MVM_OP_iscont:
     case MVM_OP_sp_namedarg_used:
     case MVM_OP_sp_findmeth:
     case MVM_OP_hllboxtype_i: