Added RemoveValidIf pass.

This is to start moving stuff out of Emitter and into separate passes

1 files changed, 26 insertions, 0 deletions

diff --git a/src/main/scala/firrtl/passes/RemoveValidIf.scala b/src/main/scala/firrtl/passes/RemoveValidIf.scala
new file mode 100644
index 00000000..4bc6162a
--- /dev/null
+++ b/src/main/scala/firrtl/passes/RemoveValidIf.scala
@@ -0,0 +1,26 @@
+package firrtl
+package passes
+import firrtl.Mappers.{ExpMap, StmtMap}
+
+// Removes ValidIf as an optimization
+object RemoveValidIf extends Pass {
+   def name = "Remove ValidIfs"
+   // Recursive. Removes ValidIf's
+   private def onExp(e: Expression): Expression = {
+      e map onExp match {
+         case ValidIf(cond, value, tpe) => value
+         case x => x
+      }
+   }
+   // Recursive.
+   private def onStmt(s: Stmt): Stmt = s map onStmt map onExp
+
+   private def onModule(m: Module): Module = {
+      m match {
+         case m:InModule => InModule(m.info, m.name, m.ports, onStmt(m.body))
+         case m:ExModule => m
+      }
+   }
+
+   def run(c: Circuit): Circuit = Circuit(c.info, c.modules.map(onModule _), c.main)
+}