[Moore] Add the SimplifyProcedures pass.

include/circt/Dialect/Moore/CMakeLists.txt

@@ -15,3 +15,7 @@ mlir_tablegen(MooreAttributes.cpp.inc -gen-attrdef-defs
   -attrdefs-dialect MooreDialect)
 add_public_tablegen_target(CIRCTMooreAttributesIncGen)
 add_dependencies(circt-headers CIRCTMooreAttributesIncGen)
+
+set(LLVM_TARGET_DEFINITIONS MoorePasses.td)
+mlir_tablegen(MoorePasses.h.inc -gen-pass-decls)
+add_public_tablegen_target(CIRCTMooreTransformsIncGen)

include/circt/Dialect/Moore/MoorePasses.h

@@ -0,0 +1,31 @@
+//===- Passes.h - Moore pass entry points -----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This header file defines prototypes that expose pass constructors.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CIRCT_DIALECT_MOORE_MOOREPASSES_H
+#define CIRCT_DIALECT_MOORE_MOOREPASSES_H
+
+#include "circt/Dialect/Moore/MooreOps.h"
+#include "mlir/Pass/Pass.h"
+
+namespace circt {
+namespace moore {
+
+std::unique_ptr<mlir::Pass> createSimplifyProceduresPass();
+
+/// Generate the code for registering passes.
+#define GEN_PASS_REGISTRATION
+#include "circt/Dialect/Moore/MoorePasses.h.inc"
+
+} // namespace moore
+} // namespace circt
+
+#endif // CIRCT_DIALECT_MOORE_MOOREPASSES_H

include/circt/Dialect/Moore/MoorePasses.td

@@ -0,0 +1,32 @@
+//===--- Passes.td - Moore pass definition file ------------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the passes that work on the Moore dialect.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CIRCT_DIALECT_MOORE_MOOREPASSES_TD
+#define CIRCT_DIALECT_MOORE_MOOREPASSES_TD
+
+include "mlir/Pass/PassBase.td"
+
+def SimplifyProcedures : Pass<"simplify-procedures", "moore::SVModuleOp"> {
+    let summary = "Simplify procedures";
+    let description = [{
+      Cause we want to introduce mem2reg in the moore dialect to eliminate the
+      local temporary variables, if the local variabels exist in the procedure
+      body, it can be promoted by mem2reg. But global/module-level variables
+      don't be promoted. So this pass is aimed at inserting a local "shadow"
+      variable in always blocks for every module-level variable that the
+      process modifies. Then perform mem2reg to eliminate the local "shadow"
+      variable.
+    }];
+    let constructor = "circt::moore::createSimplifyProceduresPass()";
+}
+
+#endif // CIRCT_DIALECT_MOORE_MOOREPASSES_TD

include/circt/InitAllPasses.h

@@ -28,6 +28,7 @@
 #include "circt/Dialect/Ibis/IbisPasses.h"
 #include "circt/Dialect/LLHD/Transforms/Passes.h"
 #include "circt/Dialect/MSFT/MSFTPasses.h"
+#include "circt/Dialect/Moore/MoorePasses.h"
 #include "circt/Dialect/OM/OMPasses.h"
 #include "circt/Dialect/Pipeline/PipelinePasses.h"
 #include "circt/Dialect/SSP/SSPPasses.h"
@@ -70,6 +71,7 @@ inline void registerAllPasses() {
   ssp::registerPasses();
   systemc::registerPasses();
   verif::registerPasses();
+  moore::registerPasses();
 }
 
 } // namespace circt

lib/Dialect/Moore/CMakeLists.txt

@@ -23,3 +23,5 @@ add_circt_dialect_library(CIRCTMoore
 )
 
 add_dependencies(circt-headers MLIRMooreIncGen)
+
+add_subdirectory(Transforms)

lib/Dialect/Moore/Transforms/CMakeLists.txt

@@ -0,0 +1,14 @@
+add_circt_dialect_library(CIRCTMooreTransforms
+SimplifyProcedures.cpp
+
+
+  DEPENDS
+  CIRCTMooreTransformsIncGen
+
+  LINK_LIBS PUBLIC
+  CIRCTMoore
+  CIRCTSupport
+  MLIRIR
+  MLIRPass
+  MLIRTransformUtils
+)

lib/Dialect/Moore/Transforms/PassDetail.h

@@ -0,0 +1,31 @@
+//===- PassDetail.h - Morre pass class details ------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Stuff shared between the different Moore passes.
+//
+//===----------------------------------------------------------------------===//
+
+// clang-tidy seems to expect the absolute path in the header guard on some
+// systems, so just disable it.
+// NOLINTNEXTLINE(llvm-header-guard)
+#ifndef DIALECT_MOORE_TRANSFORMS_PASSDETAIL_H
+#define DIALECT_MOORE_TRANSFORMS_PASSDETAIL_H
+
+#include "circt/Dialect/Moore/MoorePasses.h"
+#include "mlir/Pass/Pass.h"
+
+namespace circt {
+namespace moore {
+
+#define GEN_PASS_CLASSES
+#include "circt/Dialect/Moore/MoorePasses.h.inc"
+
+} // namespace moore
+} // namespace circt
+
+#endif // DIALECT_MOORE_TRANSFORMS_PASSDETAIL_H

lib/Dialect/Moore/Transforms/SimplifyProcedures.cpp

@@ -0,0 +1,95 @@
+//===- DeleteLocalVar.cpp - Delete local temporary variables --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the SimplifyProcedures pass.
+// Use to insert a local "shadow" variable in always blocks for every
+// module-level variable that the process modifies.
+//
+//===----------------------------------------------------------------------===//
+
+#include "PassDetail.h"
+#include "circt/Dialect/Moore/MooreOps.h"
+#include "circt/Dialect/Moore/MooreTypes.h"
+#include "mlir/IR/Builders.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace circt;
+using namespace moore;
+
+namespace {
+struct SimplifyProceduresPass
+    : public SimplifyProceduresBase<SimplifyProceduresPass> {
+  void runOnOperation() override;
+};
+} // namespace
+
+std::unique_ptr<mlir::Pass> circt::moore::createSimplifyProceduresPass() {
+  return std::make_unique<SimplifyProceduresPass>();
+}
+
+void SimplifyProceduresPass::runOnOperation() {
+  getOperation()->walk([&](ProcedureOp procedureOp) {
+    mlir::OpBuilder builder(&getContext());
+
+    // Use to collect blocking assignments that have been replaced by a "shadow"
+    // variable.
+    DenseSet<Operation *> assignOps;
+    for (auto &nestedOp : procedureOp) {
+      // Only create a "shadow" varaible for the global variable used by other
+      // operations in the procedure body.
+      if (isa<ReadOp>(nestedOp) &&
+          isa<SVModuleOp>(
+              nestedOp.getOperand(0).getDefiningOp()->getParentOp())) {
+        // Collect the users of the global variable that is mentioned above.
+        DenseSet<Operation *> users;
+        for (auto *user : nestedOp.getOperand(0).getUsers())
+          if (!users.contains(user))
+            users.insert(user);
+
+        auto varOp = cast<VariableOp>(nestedOp.getOperand(0).getDefiningOp());
+        auto varName = builder.getStringAttr("local_" + varOp.getName());
+        auto resultType = varOp.getResult().getType();
+        builder.setInsertionPointToStart(procedureOp.getBody());
+        auto readOp = builder.create<ReadOp>(
+            nestedOp.getLoc(), cast<RefType>(resultType).getNestedType(),
+            varOp.getResult());
+        auto newVarOp = builder.create<VariableOp>(nestedOp.getLoc(),
+                                                   resultType, varName, readOp);
+        builder.clearInsertionPoint();
+
+        // Replace the users of the global variable with a corresponding
+        // "shadow" variable.
+        for (auto *user : users) {
+          user->replaceUsesOfWith(user->getOperand(0), newVarOp);
+          if (isa<BlockingAssignOp>(user))
+            assignOps.insert(user);
+        }
+      }
+
+      // Ensure the global variable has the correct value. So needing to create
+      // a blocking assign for the global variable when the "shadow" variable
+      // has a new value.
+      for (auto *assignOp : assignOps)
+        if (auto localVarOp = llvm::dyn_cast_or_null<VariableOp>(
+                assignOp->getOperand(0).getDefiningOp())) {
+          auto resultType = localVarOp.getResult().getType();
+          builder.setInsertionPointAfter(assignOp);
+          auto readOp = builder.create<ReadOp>(
+              localVarOp.getLoc(), cast<RefType>(resultType).getNestedType(),
+              localVarOp.getResult());
+          builder.create<BlockingAssignOp>(
+              nestedOp.getLoc(),
+              localVarOp.getInitial().getDefiningOp()->getOperand(0), readOp);
+          builder.clearInsertionPoint();
+          assignOps.erase(assignOp);
+        }
+    }
+    return WalkResult::advance();
+  });
+}

test/Dialect/Moore/simplify-procedures.mlir

@@ -0,0 +1,53 @@
+// RUN: circt-opt --simplify-procedures %s | FileCheck %s
+
+// CHECK-LABEL: moore.module @Foo()
+moore.module @Foo() {
+  %a = moore.variable : <i32>
+  %x = moore.variable : <i32>
+  %y = moore.variable : <i32>
+  %z = moore.variable : <i32>
+  moore.procedure always_comb {
+    // CHECK: %0 = moore.read %a : i32
+    // CHECK: %local_a = moore.variable %0 : <i32>
+    // CHECK: %1 = moore.constant 1 : i32
+    %0 = moore.constant 1 : i32
+    // CHECK: moore.blocking_assign %local_a, %1 : i32
+    // CHECK: %2 = moore.read %local_a : i32
+    // CHECK: moore.blocking_assign %a, %2 : i32
+    moore.blocking_assign %a, %0 : i32
+    // CHECK: %3 = moore.read %local_a : i32
+    %1 = moore.read %a : i32
+    // CHECK: moore.blocking_assign %x, %3 : i32
+    moore.blocking_assign %x, %1 : i32
+    // CHECK: %4 = moore.read %local_a : i32
+    %2 = moore.read %a : i32
+    // CHECK: %5 = moore.constant 1 : i32
+    %3 = moore.constant 1 : i32
+    // CHECK: %6 = moore.add %4, %5 : i32
+    %4 = moore.add %2, %3 : i32
+    // CHECK: moore.blocking_assign %local_a, %6 : i32
+    // CHECK: %7 = moore.read %local_a : i32
+    // CHECK: moore.blocking_assign %a, %7 : i32
+    moore.blocking_assign %a, %4 : i32
+    // CHECK: %8 = moore.read %local_a : i32
+    %5 = moore.read %a : i32
+    // CHECK: moore.blocking_assign %y, %8 : i32
+    moore.blocking_assign %y, %5 : i32
+    // CHECK: %9 = moore.read %local_a : i32
+    %6 = moore.read %a : i32
+    // CHECK: %10 = moore.constant 1 : i32
+    %7 = moore.constant 1 : i32
+    // CHECK: %11 = moore.add %9, %10 : i32
+    %8 = moore.add %6, %7 : i32
+    // CHECK: moore.blocking_assign %local_a, %11 : i32
+    // CHECK: %12 = moore.read %local_a : i32
+    // CHECK: moore.blocking_assign %a, %12 : i32
+    moore.blocking_assign %a, %8 : i32
+    // CHECK: %13 = moore.read %local_a : i32
+    %9 = moore.read %a : i32
+    // CHECK: moore.blocking_assign %z, %13 : i32
+    moore.blocking_assign %z, %9 : i32
+  }
+  // CHECK: moore.output
+  moore.output
+}

tools/circt-opt/CMakeLists.txt

@@ -51,6 +51,7 @@ target_link_libraries(circt-opt
   CIRCTCombToLLVM
   CIRCTLLHDTransforms
   CIRCTMoore
+  CIRCTMooreTransforms
   CIRCTMooreToCore
   CIRCTMSFT
   CIRCTMSFTTransforms