add emitter for optimized low firrtl (#2304)

* rearrange passes to enable optimized firrtl emission

* Support ConstProp on padded arguments to comparisons with literals

* Move shr legalization logic into ConstProp

Continue calling ConstProp of shr in Legalize.

Co-authored-by: Jack Koenig <koenig@sifive.com>

Co-authored-by: Jack Koenig <koenig@sifive.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/src/test/scala/firrtlTests/LoFirrtlOptimizedEmitterTests.scala b/src/test/scala/firrtlTests/LoFirrtlOptimizedEmitterTests.scala
new file mode 100644
index 00000000..6f1c56c5
--- /dev/null
+++ b/src/test/scala/firrtlTests/LoFirrtlOptimizedEmitterTests.scala
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package firrtlTests
+
+import firrtl._
+import firrtl.stage._
+import firrtl.util.BackendCompilationUtilities
+import org.scalatest.flatspec.AnyFlatSpec
+
+class LoFirrtlOptimizedEmitterTests extends AnyFlatSpec {
+  behavior.of("LoFirrtlOptimizedEmitter")
+
+  it should "generate valid firrtl for AddNot" in { compileAndParse("AddNot") }
+  it should "generate valid firrtl for FPU" in { compileAndParse("FPU") }
+  it should "generate valid firrtl for HwachaSequencer" in { compileAndParse("HwachaSequencer") }
+  it should "generate valid firrtl for ICache" in { compileAndParse("ICache") }
+  it should "generate valid firrtl for Ops" in { compileAndParse("Ops") }
+  it should "generate valid firrtl for Rob" in { compileAndParse("Rob") }
+  it should "generate valid firrtl for RocketCore" in { compileAndParse("RocketCore") }
+
+  private def compileAndParse(name: String): Unit = {
+    val testDir = os.RelPath(
+      BackendCompilationUtilities.createTestDirectory(
+        "LoFirrtlOptimizedEmitter_should_generate_valid_firrtl_for" + name
+      )
+    )
+    val inputFile = testDir / s"$name.fir"
+    val outputFile = testDir / s"$name.opt.lo.fir"
+
+    BackendCompilationUtilities.copyResourceToFile(s"/regress/${name}.fir", (os.pwd / inputFile).toIO)
+
+    val stage = new FirrtlStage
+    // run low-opt emitter
+    val args = Array(
+      "-ll",
+      "error", // surpress warnings to keep test output clean
+      "--target-dir",
+      testDir.toString,
+      "-i",
+      inputFile.toString,
+      "-E",
+      "low-opt"
+    )
+    val res = stage.execute(args, Seq())
+
+    // load in result to check
+    stage.execute(Array("--target-dir", testDir.toString, "-i", outputFile.toString()), Seq())
+  }
+}