Rename dffmuxext -> dffmux, also remove constants in dff+mux

4 files changed, 91 insertions, 57 deletions

diff --git a/passes/pmgen/Makefile.inc b/passes/pmgen/Makefile.inc
index 6648e2ec0..98691d0fe 100644
--- a/passes/pmgen/Makefile.inc
+++ b/passes/pmgen/Makefile.inc
@@ -27,7 +27,7 @@ $(eval $(call add_extra_objs,passes/pmgen/peepopt_pm.h))
 
 PEEPOPT_PATTERN  = passes/pmgen/peepopt_shiftmul.pmg
 PEEPOPT_PATTERN += passes/pmgen/peepopt_muldiv.pmg
-PEEPOPT_PATTERN += passes/pmgen/peepopt_dffmuxext.pmg
+PEEPOPT_PATTERN += passes/pmgen/peepopt_dffmux.pmg
 
 passes/pmgen/peepopt_pm.h: passes/pmgen/pmgen.py $(PEEPOPT_PATTERN)
 	$(P) mkdir -p passes/pmgen && python3 $< -o $@ -p peepopt $(filter-out $<,$^)
diff --git a/passes/pmgen/peepopt.cc b/passes/pmgen/peepopt.cc
index b57d26cef..72b02127a 100644
--- a/passes/pmgen/peepopt.cc
+++ b/passes/pmgen/peepopt.cc
@@ -60,7 +60,7 @@ struct PeepoptPass : public Pass {
 				peepopt_pm pm(module, module->selected_cells());
 				pm.run_shiftmul();
 				pm.run_muldiv();
-				pm.run_dffmuxext();
+				pm.run_dffmux();
 			}
 		}
 	}
diff --git a/passes/pmgen/peepopt_dffmux.pmg b/passes/pmgen/peepopt_dffmux.pmg
new file mode 100644
index 000000000..4fc8e3b4c
--- /dev/null
+++ b/passes/pmgen/peepopt_dffmux.pmg
@@ -0,0 +1,89 @@
+pattern dffmux
+
+state <IdString> muxAB
+
+match dff
+	select dff->type == $dff
+	select GetSize(port(dff, \D)) > 1
+endmatch
+
+match mux
+	select mux->type == $mux
+	select GetSize(port(mux, \Y)) > 1
+	choice <IdString> AB {\A, \B}
+	//select port(mux, AB)[GetSize(port(mux, \Y))-1].wire
+	index <SigSpec> port(mux, \Y) === port(dff, \D)
+	define <IdString> BA (AB == \A ? \B : \A)
+	index <SigSpec> port(mux, BA) === port(dff, \Q)
+	set muxAB AB
+endmatch
+
+code
+	SigSpec &D = mux->connections_.at(muxAB);
+	SigSpec &Q = dff->connections_.at(\Q);
+	int width = GetSize(D);
+
+	SigSpec AB = port(mux, muxAB);
+	if (AB[width-1] == AB[width-2]) {
+		did_something = true;
+
+		SigBit sign = D[width-1];
+		bool is_signed = sign.wire;
+		int i;
+		for (i = width-1; i >= 2; i--) {
+			if (!is_signed) {
+				module->connect(Q[i], sign);
+				if (D[i-1] != sign)
+					break;
+			}
+			else {
+				module->connect(Q[i], Q[i-1]);
+				if (D[i-2] != sign)
+					break;
+			}
+		}
+
+		mux->connections_.at(\A).remove(i, width-i);
+		mux->connections_.at(\B).remove(i, width-i);
+		mux->connections_.at(\Y).remove(i, width-i);
+		mux->fixup_parameters();
+		dff->connections_.at(\D).remove(i, width-i);
+		dff->connections_.at(\Q).remove(i, width-i);
+		dff->fixup_parameters();
+
+		log("dffmux pattern in %s: dff=%s, mux=%s; removed top %d bits.\n", log_id(module), log_id(dff), log_id(mux), width-i);
+		accept;
+	}
+	else {
+		int count = 0;
+		for (int i = width-1; i >= 0; i--) {
+			if (AB[i].wire)
+				continue;
+			Wire *w = Q[i].wire;
+			auto it = w->attributes.find(\init);
+			State init;
+			if (it != w->attributes.end())
+				init = it->second[Q[i].offset];
+			else
+				init = State::Sx;
+
+			if (init == State::Sx || init == AB[i].data) {
+				count++;
+				module->connect(Q[i], AB[i]);
+				mux->connections_.at(\A).remove(i);
+				mux->connections_.at(\B).remove(i);
+				mux->connections_.at(\Y).remove(i);
+				dff->connections_.at(\D).remove(i);
+				dff->connections_.at(\Q).remove(i);
+			}
+		}
+		if (count > 0) {
+			did_something = true;
+			mux->fixup_parameters();
+			dff->fixup_parameters();
+		}
+
+		log("dffmux pattern in %s: dff=%s, mux=%s; removed %d constant bits.\n", log_id(module), log_id(dff), log_id(mux), count);
+		accept;
+	}
+endcode
diff --git a/passes/pmgen/peepopt_dffmuxext.pmg b/passes/pmgen/peepopt_dffmuxext.pmg
deleted file mode 100644
index 2465d6171..000000000
--- a/passes/pmgen/peepopt_dffmuxext.pmg
+++ /dev/null
@@ -1,55 +0,0 @@
-pattern dffmuxext
-
-state <IdString> muxAB
-
-match dff
-	select dff->type == $dff
-	select GetSize(port(dff, \D)) > 1
-endmatch
-
-match mux
-	select mux->type == $mux
-	select GetSize(port(mux, \Y)) > 1
-	choice <IdString> AB {\A, \B}
-	//select port(mux, AB)[GetSize(port(mux, \Y))-1].wire
-	index <SigSpec> port(mux, \Y) === port(dff, \D)
-	define <IdString> BA (AB == \A ? \B : \A)
-	index <SigSpec> port(mux, BA) === port(dff, \Q)
-	filter port(mux, AB)[GetSize(port(mux, \Y))-1] == port(mux, AB)[GetSize(port(mux, \Y))-2]
-	set muxAB AB
-endmatch
-
-code
-	did_something = true;
-
-	SigSpec &D = mux->connections_.at(muxAB);
-	SigSpec &Q = dff->connections_.at(\Q);
-	int width = GetSize(D);
-
-	SigBit sign = D[width-1];
-	bool is_signed = sign.wire;
-	int i;
-	for (i = width-1; i >= 2; i--) {
-		if (!is_signed) {
-			module->connect(Q[i], sign);
-			if (D[i-1] != sign)
-				break;
-		}
-		else {
-			module->connect(Q[i], Q[i-1]);
-			if (D[i-2] != sign)
-				break;
-		}
-	}
-
-	mux->connections_.at(\A).remove(i, width-i);
-	mux->connections_.at(\B).remove(i, width-i);
-	mux->connections_.at(\Y).remove(i, width-i);
-	mux->fixup_parameters();
-	dff->connections_.at(\D).remove(i, width-i);
-	dff->connections_.at(\Q).remove(i, width-i);
-	dff->fixup_parameters();
-
-	log("dffmuxext pattern in %s: dff=%s, mux=%s; removed top %d bits.\n", log_id(module), log_id(dff), log_id(mux), width-i);
-	accept;
-endcode