Add NoConstantPropagationAnnotation to disable constatnt propagation (#2150)

* add --no-constant-propagation to disable constant propagation

* add test

* deprecate DisableFold.

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

1 files changed, 11 insertions, 0 deletions

diff --git a/src/test/scala/firrtlTests/ConstantPropagationTests.scala b/src/test/scala/firrtlTests/ConstantPropagationTests.scala
index 60cf1b8b..bc7f92e6 100644
--- a/src/test/scala/firrtlTests/ConstantPropagationTests.scala
+++ b/src/test/scala/firrtlTests/ConstantPropagationTests.scala
@@ -908,6 +908,17 @@ class ConstantPropagationIntegrationSpec extends LowTransformSpec {
     execute(input, check, Seq(dontTouch("Child.in1")))
   }
 
+  it should "NOT optimize if no-constant-propagation is enabled" in {
+    val input =
+      """circuit Foo:
+        |  module Foo:
+        |    input a: UInt<1>
+        |    output b: UInt<1>
+        |    b <= and(UInt<1>(0), a)""".stripMargin
+    val check = parse(input).serialize
+    execute(input, check, Seq(NoConstantPropagationAnnotation))
+  }
+
   it should "still propagate constants even when there is name swapping" in {
     val input =
       """circuit Top :