diff --git a/passes/proc/proc_clean.cc b/passes/proc/proc_clean.cc
index 52141a8ec..97f4c6573 100644
--- a/passes/proc/proc_clean.cc
+++ b/passes/proc/proc_clean.cc
@@ -143,7 +143,7 @@ void proc_clean_case(RTLIL::CaseRule *cs, bool &did_something, int &count, int m
 YOSYS_NAMESPACE_END
 PRIVATE_NAMESPACE_BEGIN
 
-void proc_clean(RTLIL::Module *mod, RTLIL::Process *proc, int &total_count)
+void proc_clean(RTLIL::Module *mod, RTLIL::Process *proc, int &total_count, bool quiet)
 {
 	int count = 0;
 	bool did_something = true;
@@ -160,7 +160,7 @@ void proc_clean(RTLIL::Module *mod, RTLIL::Process *proc, int &total_count)
 		did_something = false;
 		proc_clean_case(&proc->root_case, did_something, count, -1);
 	}
-	if (count > 0)
+	if (count > 0 && !quiet)
 		log("Found and cleaned up %d empty switch%s in `%s.%s'.\n", count, count == 1 ? "" : "es", mod->name.c_str(), proc->name.c_str());
 	total_count += count;
 }
@@ -171,7 +171,10 @@ struct ProcCleanPass : public Pass {
 	{
 		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 		log("\n");
-		log("    proc_clean [selection]\n");
+		log("    proc_clean [options] [selection]\n");
+		log("\n");
+		log("    -quiet\n");
+		log("        do not print any messages.\n");
 		log("\n");
 		log("This pass removes empty parts of processes and ultimately removes a process\n");
 		log("if it contains only empty structures.\n");
@@ -180,9 +183,20 @@ struct ProcCleanPass : public Pass {
 	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
 		int total_count = 0;
-		log_header(design, "Executing PROC_CLEAN pass (remove empty switches from decision trees).\n");
+		bool quiet = false;
 
-		extra_args(args, 1, design);
+		if (find(args.begin(), args.end(), "-quiet") == args.end())
+			log_header(design, "Executing PROC_CLEAN pass (remove empty switches from decision trees).\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			if (args[argidx] == "-quiet") {
+				quiet = true;
+				continue;
+			}
+		}
+		extra_args(args, argidx, design);
 
 		for (auto mod : design->modules()) {
 			std::vector<RTLIL::IdString> delme;
@@ -191,10 +205,11 @@ struct ProcCleanPass : public Pass {
 			for (auto &proc_it : mod->processes) {
 				if (!design->selected(mod, proc_it.second))
 					continue;
-				proc_clean(mod, proc_it.second, total_count);
+				proc_clean(mod, proc_it.second, total_count, quiet);
 				if (proc_it.second->syncs.size() == 0 && proc_it.second->root_case.switches.size() == 0 &&
 						proc_it.second->root_case.actions.size() == 0) {
-					log("Removing empty process `%s.%s'.\n", log_id(mod), proc_it.second->name.c_str());
+					if (!quiet)
+						log("Removing empty process `%s.%s'.\n", log_id(mod), proc_it.second->name.c_str());
 					delme.push_back(proc_it.first);
 				}
 			}
@@ -204,7 +219,8 @@ struct ProcCleanPass : public Pass {
 			}
 		}
 
-		log("Cleaned up %d empty switch%s.\n", total_count, total_count == 1 ? "" : "es");
+		if (!quiet)
+			log("Cleaned up %d empty switch%s.\n", total_count, total_count == 1 ? "" : "es");
 	}
 } ProcCleanPass;