From 427095ad97ac31e994fee3d083eb18f78e701004 Mon Sep 17 00:00:00 2001
From: Jack Koenig
Date: Thu, 6 Jul 2017 18:16:33 -0700
Subject: Fix ConstProp bug where multiple names would swap with one

Fixes issue in https://github.com/freechipsproject/rocket-chip/pull/848
---
 .../firrtlTests/ConstantPropagationTests.scala     | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)

(limited to 'src/test')

diff --git a/src/test/scala/firrtlTests/ConstantPropagationTests.scala b/src/test/scala/firrtlTests/ConstantPropagationTests.scala
index 75c43cf2..380d53e5 100644
--- a/src/test/scala/firrtlTests/ConstantPropagationTests.scala
+++ b/src/test/scala/firrtlTests/ConstantPropagationTests.scala
@@ -448,6 +448,33 @@ class ConstantPropagationSpec extends FirrtlFlatSpec {
     node _T_1 = n
     z <= n
     n <= x
+"""
+      (parse(exec(input))) should be (parse(check))
+   }
+
+   // =============================
+   "ConstProp" should "only swap a given name with one other name" in {
+      val input =
+"""circuit Top :
+  module Top :
+    input x : UInt<1>
+    input y : UInt<1>
+    output z : UInt<3>
+    node _T_1 = add(x, y)
+    node n = _T_1
+    node m = _T_1
+    z <= add(n, m)
+"""
+      val check =
+"""circuit Top :
+  module Top :
+    input x : UInt<1>
+    input y : UInt<1>
+    output z : UInt<3>
+    node n = add(x, y)
+    node _T_1 = n
+    node m = n
+    z <= add(n, n)
 """
       (parse(exec(input))) should be (parse(check))
    }
-- 
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