check llvm version

Author: zhiics

tests/python/relay/test_op_qnn_conv2d.py

@@ -642,6 +642,10 @@ def test_broadcast_layout():
 
 
 def test_conv2d_int8():
+    if tvm.codegen.llvm_version_major() < 6:
+        print("Skipping due to LLVM version being {}<6".format(
+            tvm.codegen.llvm_version_major()))
+
     data = relay.var("data", shape=(1, 28, 28, 128), dtype='uint8')
     kernel = relay.var("w", shape=(3, 3, 128, 256), dtype='int8')
     conv = relay.nn.conv2d(