[IR&Pass] Add DCE Pass for new ir. (#54935)

paddle/ir/CMakeLists.txt

@@ -40,6 +40,7 @@ endif()
 add_subdirectory(core)
 add_subdirectory(pass)
 add_subdirectory(pattern_rewrite)
+add_subdirectory(transforms)
 
 if(WIN32)
   if(WITH_SHARED_IR)

paddle/ir/transforms/CMakeLists.txt

+file(GLOB PATTERN_SRCS "*.cc")
+
+ir_library(
+  ir_builtin_transforms
+  SRCS
+  ${PATTERN_SRCS}
+  DEPS
+  ir_core
+  ir_pattern_rewrite
+  ir_pass)

paddle/ir/transforms/dce.cc

+// Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/ir/transforms/dce.h"
+#include <memory>
+#include "paddle/ir/core/builtin_op.h"
+#include "paddle/ir/pass/pass.h"
+
+namespace {
+
+// TODO(wilber): After support SideEffectTrait, Only NoSideEffectTrait op can be
+// removed by dce pass.
+// Now just a naive implementation.
+class DCEPass : public ir::Pass {
+ public:
+  DCEPass() : ir::Pass("DCEPass", 0) {}
+
+  void Run(ir::Operation *op) override {
+    auto module_op = op->dyn_cast<ir::ModuleOp>();
+    IR_ENFORCE(module_op, "DCEPass should run on module op.");
+    auto *block = module_op.block();
+    std::vector<ir::Operation> erased_op;
+    for (auto it = block->begin(); it != block->end(); ++it) {
+      // TODO(wilber): Support NoSideEffect trait.
+      // if (!(*it)->HasTrait<NoSideEffect>()) continue;
+
+      bool use_empty = true;
+      for (uint32_t i = 0; i < (*it)->num_results(); ++i) {
+        use_empty &= (*it)->result(i).use_empty();
+      }
+      if (use_empty && (*it)->name() != "pd.fetch") {
+        erased_op.push_back(**it);
+      }
+    }
+
+    for (auto ep : erased_op) block->erase(ep);
+  }
+
+  bool CanApplyOn(ir::Operation *op) const override {
+    return op->name() == "builtin.module" && op->num_regions() > 0;
+  }
+};
+
+}  // namespace
+
+namespace ir {
+
+std::unique_ptr<Pass> CreateDCEPass() { return std::make_unique<DCEPass>(); }
+
+}  // namespace ir

paddle/ir/transforms/dce.h

+// Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <memory>
+#include "paddle/ir/core/dll_decl.h"
+
+namespace ir {
+class Pass;
+
+IR_API std::unique_ptr<Pass> CreateDCEPass();
+
+}  // namespace ir

test/cpp/ir/pattern_rewrite/pattern_rewrite_test.cc

@@ -22,6 +22,7 @@
 #include "paddle/ir/core/builder.h"
 #include "paddle/ir/core/builtin_attribute.h"
 #include "paddle/ir/core/builtin_dialect.h"
+#include "paddle/ir/core/builtin_op.h"
 #include "paddle/ir/core/cast_utils.h"
 #include "paddle/ir/core/dialect.h"
 #include "paddle/ir/core/enforce.h"
@@ -34,6 +35,7 @@
 #include "paddle/ir/pattern_rewrite/pattern_applicator.h"
 #include "paddle/ir/pattern_rewrite/pattern_match.h"
 #include "paddle/ir/pattern_rewrite/pattern_rewrite_driver.h"
+#include "paddle/ir/transforms/dce.h"
 
 // NOTE(zhangbo9674): File pd_op.h is generated by op_gen.py, see details in
 // paddle/fluid/ir/dialect/CMakeLists.txt.
@@ -235,7 +237,7 @@ class TestPass : public ir::Pass {
     ir::FrozenRewritePatternSet frozen_ps(std::move(ps));
     ir::GreedyRewriteConfig cfg;
     cfg.use_top_down_traversal = true;
-    cfg.max_iterations = 1;
+    cfg.max_iterations = 10;
     ir::ApplyPatternsGreedily(op->region(0), frozen_ps, cfg);
   }
 
@@ -255,10 +257,10 @@ void BuildProgram(ir::Builder &builder) {  // NOLINT
   auto transpose1_op = builder.Build<paddle::dialect::TransposeOp>(
       full_op_output, std::vector<int>{0, 2, 3, 1});
 
-  builder.Build<paddle::dialect::TransposeOp>(transpose1_op.out(),
-                                              std::vector<int>{0, 3, 1, 2});
+  auto transpose2_op = builder.Build<paddle::dialect::TransposeOp>(
+      transpose1_op.out(), std::vector<int>{0, 3, 1, 2});
 
-  // builder.Build<paddle::dialect::FetchOp>(transpose2_op.out());
+  builder.Build<paddle::dialect::FetchOp>(transpose2_op.out(), "out");
 }
 
 // TODO(wilber): Add a normal test.
@@ -268,10 +270,11 @@ TEST(PatternRewrite, GreedyPatternRewriteDriver) {
   ir::Program program(ctx);
   ir::Builder builder = ir::Builder(ctx, program.block());
   BuildProgram(builder);
-  EXPECT_EQ(program.block()->size(), 3u);
+  EXPECT_EQ(program.block()->size(), 4u);
 
   ir::PassManager pm(ctx);
   pm.AddPass(std::make_unique<TestPass>());
+  pm.AddPass(ir::CreateDCEPass());
   std::stringstream o1, o2;
   program.Print(o1);
   LOG(INFO) << o1.str();