diff options
Diffstat (limited to 'src/main/scala/firrtl/passes')
| -rw-r--r-- | src/main/scala/firrtl/passes/Passes.scala | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/src/main/scala/firrtl/passes/Passes.scala b/src/main/scala/firrtl/passes/Passes.scala index bb65201b..04bfb19c 100644 --- a/src/main/scala/firrtl/passes/Passes.scala +++ b/src/main/scala/firrtl/passes/Passes.scala @@ -183,19 +183,23 @@ object ExpandConnects extends Pass { object Legalize extends Pass { private def legalizeShiftRight(e: DoPrim): Expression = { require(e.op == Shr) - val amount = e.consts.head.toInt - val width = bitWidth(e.args.head.tpe) - lazy val msb = width - 1 - if (amount >= width) { - e.tpe match { - case UIntType(_) => zero - case SIntType(_) => - val bits = DoPrim(Bits, e.args, Seq(msb, msb), BoolType) - DoPrim(AsSInt, Seq(bits), Seq.empty, SIntType(IntWidth(1))) - case t => error(s"Unsupported type $t for Primop Shift Right") - } - } else { - e + e.args.head match { + case _: UIntLiteral | _: SIntLiteral => ConstantPropagation.foldShiftRight(e) + case _ => + val amount = e.consts.head.toInt + val width = bitWidth(e.args.head.tpe) + lazy val msb = width - 1 + if (amount >= width) { + e.tpe match { + case UIntType(_) => zero + case SIntType(_) => + val bits = DoPrim(Bits, e.args, Seq(msb, msb), BoolType) + DoPrim(AsSInt, Seq(bits), Seq.empty, SIntType(IntWidth(1))) + case t => error(s"Unsupported type $t for Primop Shift Right") + } + } else { + e + } } } private def legalizeBitExtract(expr: DoPrim): Expression = { |