diff --git a/techlibs/common/synth.cc b/techlibs/common/synth.cc
index d9565131e..ccfa76e02 100644
--- a/techlibs/common/synth.cc
+++ b/techlibs/common/synth.cc
@@ -51,6 +51,9 @@ struct SynthPass : public ScriptPass
 		log("    -encfile <file>\n");
 		log("        passed to 'fsm_recode' via 'fsm'\n");
 		log("\n");
+		log("    -lut <k>\n");
+		log("        perform synthesis for a k-LUT architecture.\n");
+		log("\n");
 		log("    -nofsm\n");
 		log("        do not run FSM optimization\n");
 		log("\n");
@@ -80,6 +83,7 @@ struct SynthPass : public ScriptPass
 
 	string top_module, fsm_opts, memory_opts;
 	bool autotop, flatten, noalumacc, nofsm, noabc, noshare;
+	int lut;
 
 	void clear_flags() YS_OVERRIDE
 	{
@@ -89,6 +93,7 @@ struct SynthPass : public ScriptPass
 
 		autotop = false;
 		flatten = false;
+		lut = 0;
 		noalumacc = false;
 		nofsm = false;
 		noabc = false;
@@ -130,6 +135,10 @@ struct SynthPass : public ScriptPass
 				flatten = true;
 				continue;
 			}
+			if (args[argidx] == "-lut") {
+				lut = atoi(args[++argidx].c_str());
+				continue;
+			}
 			if (args[argidx] == "-nofsm") {
 				nofsm = true;
 				continue;
@@ -186,19 +195,23 @@ struct SynthPass : public ScriptPass
 		{
 			run("proc");
 			if (help_mode || flatten)
-				run("flatten", "(if -flatten)");
+				run("flatten", "  (if -flatten)");
 			run("opt_expr");
 			run("opt_clean");
 			run("check");
 			run("opt");
 			run("wreduce");
+			if (help_mode)
+				run("techmap -map +/cmp2lut.v", " (if -lut)");
+			else
+				run(stringf("techmap -map +/cmp2lut.v -D LUT_WIDTH=%d", lut));
 			if (!noalumacc)
-				run("alumacc");
+				run("alumacc", "  (unless -noalumacc)");
 			if (!noshare)
-				run("share");
+				run("share", "    (unless -noshare)");
 			run("opt");
 			if (!nofsm)
-				run("fsm" + fsm_opts);
+				run("fsm" + fsm_opts, "      (unless -nofsm)");
 			run("opt -fast");
 			run("memory -nomap" + memory_opts);
 			run("opt_clean");
@@ -210,12 +223,33 @@ struct SynthPass : public ScriptPass
 			run("memory_map");
 			run("opt -full");
 			run("techmap");
+			if (help_mode)
+			{
+				run("techmap -map +/gate2lut.v", "(if -noabc and -lut)");
+				run("clean; opt_lut", "           (if -noabc and -lut)");
+			}
+			else if (noabc && lut)
+			{
+				run(stringf("techmap -map +/gate2lut.v -D LUT_WIDTH=%d", lut));
+				run("clean; opt_lut");
+			}
 			run("opt -fast");
 
 			if (!noabc) {
 		#ifdef YOSYS_ENABLE_ABC
-				run("abc -fast");
-				run("opt -fast");
+				if (help_mode)
+				{
+					run("abc -fast", "       (unless -noabc, unless -lut)");
+					run("abc -fast -lut k", "(unless -noabc, if -lut)");
+				}
+				else
+				{
+					if (lut)
+						run(stringf("abc -fast -lut %d", lut));
+					else
+						run("abc -fast");
+				}
+				run("opt -fast", "       (unless -noabc)");
 		#endif
 			}
 		}
diff --git a/techlibs/ice40/synth_ice40.cc b/techlibs/ice40/synth_ice40.cc
index 626f6d381..f900453e8 100644
--- a/techlibs/ice40/synth_ice40.cc
+++ b/techlibs/ice40/synth_ice40.cc
@@ -226,7 +226,7 @@ struct SynthIce40Pass : public ScriptPass
 
 		if (check_label("coarse"))
 		{
-			run("synth -run coarse");
+			run("synth -lut 4 -run coarse");
 		}
 
 		if (!nobram && check_label("bram", "(skip if -nobram)"))