Revert removal of bit extraction const prop for literals (#857)

See https://github.com/freechipsproject/chisel3/issues/867 for future API discussion

1 files changed, 19 insertions, 0 deletions

diff --git a/src/test/scala/chiselTests/UIntOps.scala b/src/test/scala/chiselTests/UIntOps.scala
index 149ec3c4..d583c0bb 100644
--- a/src/test/scala/chiselTests/UIntOps.scala
+++ b/src/test/scala/chiselTests/UIntOps.scala
@@ -96,6 +96,21 @@ class NegativeShift(t: => Bits) extends Module {
   Reg(t) >> -1
 }
 
+class UIntLitExtractTester extends BasicTester {
+  assert("b101010".U(2) === false.B)
+  assert("b101010".U(3) === true.B)
+  assert("b101010".U(100) === false.B)
+  assert("b101010".U(3, 0) === "b1010".U)
+  assert("b101010".U(9, 0) === "b0000101010".U)
+
+  assert("b101010".U(6.W)(2) === false.B)
+  assert("b101010".U(6.W)(3) === true.B)
+  assert("b101010".U(6.W)(100) === false.B)
+  assert("b101010".U(6.W)(3, 0) === "b1010".U)
+  assert("b101010".U(6.W)(9, 0) === "b0000101010".U)
+  stop()
+}
+
 class UIntOpsSpec extends ChiselPropSpec with Matchers {
   // Disable shrinking on error.
   implicit val noShrinkListVal = Shrink[List[Int]](_ => Stream.empty)
@@ -120,5 +135,9 @@ class UIntOpsSpec extends ChiselPropSpec with Matchers {
   property("Negative shift amounts are invalid") {
     a [ChiselException] should be thrownBy { elaborate(new NegativeShift(UInt())) }
   }
+
+  property("Bit extraction on literals should work for all non-negative indices") {
+    assertTesterPasses(new UIntLitExtractTester)
+  }
 }