From b42620e4907642775613a194473a4ee5860186a3 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Thu, 13 Dec 2018 02:35:46 +0000
Subject: [PATCH] back.rtlil: match shape of $mux ports A/B/Y.

---
 nmigen/back/rtlil.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/nmigen/back/rtlil.py b/nmigen/back/rtlil.py
index c008369..808ae32 100644
--- a/nmigen/back/rtlil.py
+++ b/nmigen/back/rtlil.py
@@ -349,14 +349,17 @@ class _ValueTransformer(xfrm.ValueTransformer):
         lhs_bits, lhs_sign = lhs.shape()
         rhs_bits, rhs_sign = rhs.shape()
         res_bits, res_sign = node.shape()
+        lhs_bits = rhs_bits = res_bits = max(lhs_bits, rhs_bits, res_bits)
+        lhs_wire = self.match_shape(lhs, lhs_bits, lhs_sign)
+        rhs_wire = self.match_shape(rhs, rhs_bits, rhs_sign)
         res = self.rtlil.wire(width=res_bits)
         self.rtlil.cell("$mux", ports={
-            "\\A": self(lhs),
-            "\\B": self(rhs),
+            "\\A": lhs_wire,
+            "\\B": rhs_wire,
             "\\S": self(sel),
             "\\Y": res,
         }, params={
-            "WIDTH": max(lhs_bits, rhs_bits, res_bits)
+            "WIDTH": res_bits
         })
         return res
 
-- 
2.30.2