wreduce: Introduce -mux_undef option (aligned with opt_expr).

1 files changed, 9 insertions, 1 deletions

diff --git a/passes/opt/wreduce.cc b/passes/opt/wreduce.cc
index aaad28ef0..08ab6de6f 100644
--- a/passes/opt/wreduce.cc
+++ b/passes/opt/wreduce.cc
@@ -30,6 +30,7 @@ struct WreduceConfig
 {
 	pool<IdString> supported_cell_types;
 	bool keepdc = false;
+	bool mux_undef = false;
 
 	WreduceConfig()
 	{
@@ -83,7 +84,7 @@ struct WreduceWorker
 
 			SigBit ref = sig_a[i];
 			for (int k = 0; k < GetSize(sig_s); k++) {
-				if ((config->keepdc || (ref != State::Sx && sig_b[k*GetSize(sig_a) + i] != State::Sx)) && ref != sig_b[k*GetSize(sig_a) + i])
+				if ((config->keepdc || !config->mux_undef || (ref != State::Sx && sig_b[k*GetSize(sig_a) + i] != State::Sx)) && ref != sig_b[k*GetSize(sig_a) + i])
 					goto no_match_ab;
 				if (sig_b[k*GetSize(sig_a) + i] != State::Sx)
 					ref = sig_b[k*GetSize(sig_a) + i];
@@ -479,6 +480,9 @@ struct WreducePass : public Pass {
 		log("        Do not change the width of memory address ports. Use this options in\n");
 		log("        flows that use the 'memory_memx' pass.\n");
 		log("\n");
+		log("    -mux_undef\n");
+		log("        remove 'undef' inputs from $mux, $pmux and $_MUX_ cells\n");
+		log("\n");
 		log("    -keepdc\n");
 		log("        Do not optimize explicit don't-care values.\n");
 		log("\n");
@@ -500,6 +504,10 @@ struct WreducePass : public Pass {
 				config.keepdc = true;
 				continue;
 			}
+			if (args[argidx] == "-mux_undef") {
+				config.mux_undef = true;
+				continue;
+			}
 			break;
 		}
 		extra_args(args, argidx, design);