diff --git a/docs/source/code_examples/macro_commands/opt.ys b/docs/source/code_examples/macro_commands/opt.ys
index fe2a05f4d39..5ed6aba0ebf 100644
--- a/docs/source/code_examples/macro_commands/opt.ys
+++ b/docs/source/code_examples/macro_commands/opt.ys
@@ -13,4 +13,4 @@ do
     opt_boundary (-boundary only)
     opt_clean
     opt_expr
-while <changed design>
+while <changed design in opt_dff> (up to -max_iter iterations)
diff --git a/passes/opt/opt.cc b/passes/opt/opt.cc
index 9fc1e9490c9..e7e830aefaa 100644
--- a/passes/opt/opt.cc
+++ b/passes/opt/opt.cc
@@ -50,7 +50,7 @@ struct OptPass : public Pass {
 		log("        opt_boundary (-boundary only)\n");
 		log("        opt_clean [-purge]\n");
 		log("        opt_expr [-mux_undef] [-mux_bool] [-undriven] [-noclkinv] [-fine] [-full] [-keepdc]\n");
-		log("    while <changed design>\n");
+		log("    while <changed design> (up to -max_iter iterations)\n");
 		log("\n");
 		log("When called with -fast the following script is used instead:\n");
 		log("\n");
@@ -61,11 +61,14 @@ struct OptPass : public Pass {
 		log("        opt_hier (-hier only)\n");
 		log("        opt_boundary (-boundary only)\n");
 		log("        opt_clean [-purge]\n");
-		log("    while <changed design in opt_dff>\n");
+		log("    while <changed design in opt_dff> (up to -max_iter iterations)\n");
 		log("\n");
 		log("Note: Options in square brackets (such as [-keepdc]) are passed through to\n");
 		log("the opt_* commands when given to 'opt'.\n");
 		log("\n");
+		log("    -max_iter <number>\n");
+		log("        only run the specified number of iterations.\n");
+		log("        default: 20. use 0 for unlimited.\n");
 		log("\n");
 	}
 	void execute(std::vector<std::string> args, RTLIL::Design *design) override
@@ -80,6 +83,8 @@ struct OptPass : public Pass {
 		bool noff_mode = false;
 		bool hier_mode = false;
 		bool boundary_mode = false;
+		int max_iter = 20;
+		bool reached_max_iter = false;
 
 		log_header(design, "Executing OPT pass (performing simple optimizations).\n");
 		log_push();
@@ -155,13 +160,19 @@ struct OptPass : public Pass {
 				boundary_mode = true;
 				continue;
 			}
+			if (args[argidx] == "-max_iter" && argidx+1 < args.size()) {
+				max_iter = atoi(args[++argidx].c_str());
+				continue;
+			}
 			break;
 		}
 		extra_args(args, argidx, design);
 
 		if (fast_mode)
 		{
+			int iter = 0;
 			while (1) {
+				iter++;
 				Pass::call(design, "opt_expr" + opt_expr_args);
 				Pass::call(design, "opt_merge" + opt_merge_args);
 				design->scratchpad_unset("opt.did_something");
@@ -174,6 +185,10 @@ struct OptPass : public Pass {
 				if (boundary_mode)
 					Pass::call(design, "opt_boundary");
 				Pass::call(design, "opt_clean" + opt_clean_args);
+				if (max_iter > 0 && iter >= max_iter) {
+					reached_max_iter = true;
+					break;
+				}
 				log_header(design, "Rerunning OPT passes. (Removed registers in this run.)\n");
 			}
 			Pass::call(design, "opt_clean" + opt_clean_args);
@@ -182,7 +197,9 @@ struct OptPass : public Pass {
 		{
 			Pass::call(design, "opt_expr" + opt_expr_args);
 			Pass::call(design, "opt_merge -nomux" + opt_merge_args);
+			int iter = 0;
 			while (1) {
+				iter++;
 				design->scratchpad_unset("opt.did_something");
 				Pass::call(design, "opt_muxtree");
 				Pass::call(design, "opt_reduce" + opt_reduce_args);
@@ -199,6 +216,10 @@ struct OptPass : public Pass {
 				Pass::call(design, "opt_expr" + opt_expr_args);
 				if (design->scratchpad_get_bool("opt.did_something") == false)
 					break;
+				if (max_iter > 0 && iter >= max_iter) {
+					reached_max_iter = true;
+					break;
+				}
 				log_header(design, "Rerunning OPT passes. (Maybe there is more to do..)\n");
 			}
 		}
@@ -207,7 +228,9 @@ struct OptPass : public Pass {
 		design->sort();
 		design->check();
 
-		log_header(design, "Finished fast OPT passes.%s\n", fast_mode ? "" : " (There is nothing left to do.)");
+		const char *done_reason = reached_max_iter ? " (Reached maximum number of iterations.)" :
+				(fast_mode ? "" : " (There is nothing left to do.)");
+		log_header(design, "Finished %sOPT passes.%s\n", fast_mode ? "fast " : "", done_reason);
 		log_pop();
 	}
 } OptPass;