From 88af5b6a162ebc4fcc753794b38491e7897b702a Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Fri, 29 Mar 2013 11:19:21 +0100
Subject: [PATCH] Improved opt_share for reduce cells

---
 kernel/rtlil.cc         | 13 ++++++++++---
 kernel/rtlil.h          |  2 ++
 passes/opt/opt_share.cc | 20 ++++++++++++++++++++
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 95114469e..b0dcfe428 100644
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -566,7 +566,7 @@ void RTLIL::SigSpec::optimize()
 	check();
 }
 
-static bool compare_sigchunks(const RTLIL::SigChunk &a, const RTLIL::SigChunk &b)
+bool RTLIL::SigChunk::compare(const RTLIL::SigChunk &a, const RTLIL::SigChunk &b)
 {
 	if (a.wire != b.wire) {
 		if (a.wire == NULL || b.wire == NULL)
@@ -583,14 +583,21 @@ static bool compare_sigchunks(const RTLIL::SigChunk &a, const RTLIL::SigChunk &b
 	return a.data.bits < b.data.bits;
 }
 
+void RTLIL::SigSpec::sort()
+{
+	expand();
+	std::sort(chunks.begin(), chunks.end(), RTLIL::SigChunk::compare);
+	optimize();
+}
+
 void RTLIL::SigSpec::sort_and_unify()
 {
 	expand();
-	std::sort(chunks.begin(), chunks.end(), compare_sigchunks);
+	std::sort(chunks.begin(), chunks.end(), RTLIL::SigChunk::compare);
 	for (size_t i = 1; i < chunks.size(); i++) {
 		RTLIL::SigChunk &ch1 = chunks[i-1];
 		RTLIL::SigChunk &ch2 = chunks[i];
-		if (!compare_sigchunks(ch1, ch2) && !compare_sigchunks(ch2, ch1)) {
+		if (!RTLIL::SigChunk::compare(ch1, ch2) && !RTLIL::SigChunk::compare(ch2, ch1)) {
 			chunks.erase(chunks.begin()+i);
 			width -= chunks[i].width;
 			i--;
diff --git a/kernel/rtlil.h b/kernel/rtlil.h
index a0d7a1a37..fe88182fa 100644
--- a/kernel/rtlil.h
+++ b/kernel/rtlil.h
@@ -277,6 +277,7 @@ struct RTLIL::SigChunk {
 	bool operator <(const RTLIL::SigChunk &other) const;
 	bool operator ==(const RTLIL::SigChunk &other) const;
 	bool operator !=(const RTLIL::SigChunk &other) const;
+	static bool compare(const RTLIL::SigChunk &a, const RTLIL::SigChunk &b);
 };
 
 struct RTLIL::SigSpec {
@@ -291,6 +292,7 @@ struct RTLIL::SigSpec {
 	SigSpec(RTLIL::State bit, int width = 1);
 	void expand();
 	void optimize();
+	void sort();
 	void sort_and_unify();
 	void replace(const RTLIL::SigSpec &pattern, const RTLIL::SigSpec &with);
 	void replace(const RTLIL::SigSpec &pattern, const RTLIL::SigSpec &with, RTLIL::SigSpec *other) const;
diff --git a/passes/opt/opt_share.cc b/passes/opt/opt_share.cc
index 6dd4daa0b..43d1a57e1 100644
--- a/passes/opt/opt_share.cc
+++ b/passes/opt/opt_share.cc
@@ -76,6 +76,18 @@ struct OptShareWorker
 				alt_conn["\\B"] = conn->at("\\A");
 			}
 			conn = &alt_conn;
+		} else
+		if (cell->type == "$reduce_xor" || cell->type == "$reduce_xnor") {
+			alt_conn = *conn;
+			assign_map.apply(alt_conn.at("\\A"));
+			alt_conn.at("\\A").sort();
+			conn = &alt_conn;
+		} else
+		if (cell->type == "$reduce_and" || cell->type == "$reduce_or" || cell->type == "$reduce_bool") {
+			alt_conn = *conn;
+			assign_map.apply(alt_conn.at("\\A"));
+			alt_conn.at("\\A").sort_and_unify();
+			conn = &alt_conn;
 		}
 
 		for (auto &it : *conn) {
@@ -151,6 +163,14 @@ struct OptShareWorker
 				conn2["\\A"] = conn2["\\B"];
 				conn2["\\B"] = tmp;
 			}
+		} else
+		if (cell1->type == "$reduce_xor" || cell1->type == "$reduce_xnor") {
+			conn1["\\A"].sort();
+			conn2["\\A"].sort();
+		} else
+		if (cell1->type == "$reduce_and" || cell1->type == "$reduce_or" || cell1->type == "$reduce_bool") {
+			conn1["\\A"].sort_and_unify();
+			conn2["\\A"].sort_and_unify();
 		}
 
 		if (conn1 != conn2) {
-- 
2.30.2