Don't use ResolvedAnnotationPaths in ConstProp nor DCE (#1896)

Both use EliminateTargetPaths to duplicate modules based on annotations.
Currently, EliminateTargetPaths API is a little too limited so it
duplicates more than it should which effectively breaks Dedup whenever
DontTouchAnnotations are present.

Also, make ConstProp and DCE treat all HasDontTouches as local
annotations even if they are instance annotations. This is more
conservative but it is generally better to preserve deduplication than
to maximally optimize every instance.

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/src/test/scala/firrtlTests/ConstantPropagationTests.scala b/src/test/scala/firrtlTests/ConstantPropagationTests.scala
index 6ab54159..cc6377ee 100644
--- a/src/test/scala/firrtlTests/ConstantPropagationTests.scala
+++ b/src/test/scala/firrtlTests/ConstantPropagationTests.scala
@@ -1528,6 +1528,41 @@ class ConstantPropagationIntegrationSpec extends LowTransformSpec {
     execute(input, check, Seq.empty)
   }
 
+  "ConstProp" should "compose with Dedup and not duplicate modules " in {
+    val input =
+      """circuit Top :
+        |  module child :
+        |    input x : UInt<1>
+        |    output z : UInt<1>
+        |    z <= not(x)
+        |  module child_1 :
+        |    input x : UInt<1>
+        |    output z : UInt<1>
+        |    z <= not(x)
+        |  module Top :
+        |    input x : UInt<1>
+        |    output z : UInt<1>
+        |    inst c of child
+        |    inst c_1 of child_1
+        |    c.x <= x
+        |    c_1.x <= x
+        |    z <= and(c.z, c_1.z)""".stripMargin
+    val check =
+      """circuit Top :
+        |  module child :
+        |    input x : UInt<1>
+        |    output z : UInt<1>
+        |    z <= not(x)
+        |  module Top :
+        |    input x : UInt<1>
+        |    output z : UInt<1>
+        |    inst c of child
+        |    inst c_1 of child
+        |    z <= and(c.z, c_1.z)
+        |    c.x <= x
+        |    c_1.x <= x""".stripMargin
+    execute(input, check, Seq(dontTouch("child.z"), dontTouch("child_1.z")))
+  }
 }
 
 class ConstantPropagationEquivalenceSpec extends FirrtlFlatSpec {