From fe80b39f56fb650cc67bed09f29ea42e0e5f6e52 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Tue, 15 May 2018 14:02:27 +0200
Subject: [PATCH] Fix iopadmap for loops between tristate IO buffers

Signed-off-by: Clifford Wolf <clifford@clifford.at>
---
 passes/techmap/iopadmap.cc | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/passes/techmap/iopadmap.cc b/passes/techmap/iopadmap.cc
index c20081c64..690ba87ed 100644
--- a/passes/techmap/iopadmap.cc
+++ b/passes/techmap/iopadmap.cc
@@ -175,6 +175,8 @@ struct IopadmapPass : public Pass {
 			if (!toutpad_celltype.empty() || !tinoutpad_celltype.empty())
 			{
 				dict<SigBit, pair<IdString, pool<IdString>>> tbuf_bits;
+				pool<pair<IdString, IdString>> norewrites;
+				SigMap rewrites;
 
 				for (auto cell : module->cells())
 					if (cell->type == "$_TBUF_") {
@@ -246,6 +248,9 @@ struct IopadmapPass : public Pass {
 
 							module->remove(tbuf_cell);
 							skip_wires[wire->name].insert(i);
+
+							norewrites.insert(make_pair(cell->name, RTLIL::escape_id(tinoutpad_portname4)));
+							rewrites.add(sigmap(wire_bit), owire);
 							continue;
 						}
 
@@ -283,6 +288,22 @@ struct IopadmapPass : public Pass {
 						}
 					}
 				}
+
+				if (GetSize(norewrites))
+				{
+					for (auto cell : module->cells())
+					for (auto port : cell->connections())
+					{
+						if (norewrites.count(make_pair(cell->name, port.first)))
+							continue;
+
+						SigSpec orig_sig = sigmap(port.second);
+						SigSpec new_sig = rewrites(orig_sig);
+
+						if (orig_sig != new_sig)
+							cell->setPort(port.first, new_sig);
+					}
+				}
 			}
 
 			for (auto wire : module->selected_wires())
-- 
2.30.2