diff --git a/afl_transforms/tools/zax/zax_base.cpp b/afl_transforms/tools/zax/zax_base.cpp
index f522bff111a04bc89f6c65c7b01548cb772c3cbf..48bb2d8832ca444ec07d5dc6037ae2e58df0c11f 100644
--- a/afl_transforms/tools/zax/zax_base.cpp
+++ b/afl_transforms/tools/zax/zax_base.cpp
@@ -620,6 +620,8 @@ BasicBlockSet_t ZaxBase_t::getBlocksToInstrument(const ControlFlowGraph_t &cfg)
 }
 void ZaxBase_t::filterBlocksByDomgraph(BasicBlockSet_t& in_out,  const DominatorGraph_t* dg)
 {
+	if(!m_domgraph_optimize)
+		return;
 	auto copy=in_out;
 	for(auto block : copy)
 	{