[SandboxVec] Boilerplate for vectorization passes (#108603)

This patch implements a new empty pass for the Bottom-up vectorizer and
creates a pass pipeline that includes it.
The SandboxVectorizer LLVM pass runs the Sandbox IR pass pipeline.

Author: vporpo

llvm/include/llvm/SandboxIR/Pass.h

@@ -40,6 +40,8 @@ class Pass {
   virtual void print(raw_ostream &OS) const { OS << Name; }
   LLVM_DUMP_METHOD virtual void dump() const;
 #endif
+  /// Similar to print() but adds a newline. Used for testing.
+  void printPipeline(raw_ostream &OS) const { OS << Name << "\n"; }
 };
 
 /// A pass that runs on a sandbox::Function.

llvm/include/llvm/SandboxIR/PassManager.h

@@ -49,6 +49,7 @@ class PassManager : public ParentPass {
   void print(raw_ostream &OS) const override {
     OS << this->getName();
     OS << "(";
+    // TODO: This should call Pass->print(OS) because Pass may be a PM.
     interleave(Passes, OS, [&OS](auto *Pass) { OS << Pass->getName(); }, ",");
     OS << ")";
   }
@@ -57,6 +58,12 @@ class PassManager : public ParentPass {
     dbgs() << "\n";
   }
 #endif
+  /// Similar to print() but prints one pass per line. Used for testing.
+  void printPipeline(raw_ostream &OS) const {
+    OS << this->getName() << "\n";
+    for (const auto &PassPtr : Passes)
+      PassPtr->printPipeline(OS);
+  }
 };
 
 class FunctionPassManager final

llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h

@@ -0,0 +1,28 @@
+//===- BottomUpVec.h --------------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// A Bottom-Up Vectorizer pass.
+//
+
+#ifndef LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_BOTTOMUPVEC_H
+#define LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_BOTTOMUPVEC_H
+
+#include "llvm/SandboxIR/Pass.h"
+
+namespace llvm::sandboxir {
+
+class BottomUpVec final : public FunctionPass {
+
+public:
+  BottomUpVec() : FunctionPass("bottom-up-vec") {}
+  bool runOnFunction(Function &F) final;
+};
+
+} // namespace llvm::sandboxir
+
+#endif // LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_BOTTOMUPVEC_H

llvm/lib/Transforms/Vectorize/CMakeLists.txt

@@ -3,6 +3,7 @@ add_llvm_component_library(LLVMVectorize
   LoopIdiomVectorize.cpp
   LoopVectorizationLegality.cpp
   LoopVectorize.cpp
+  SandboxVectorizer/Passes/BottomUpVec.cpp
   SandboxVectorizer/SandboxVectorizer.cpp
   SLPVectorizer.cpp
   Vectorize.cpp

llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.cpp

@@ -0,0 +1,13 @@
+//===- BottomUpVec.cpp - A bottom-up vectorizer pass ----------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h"
+
+using namespace llvm::sandboxir;
+
+bool BottomUpVec::runOnFunction(Function &F) { return false; }

llvm/lib/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizer.cpp

@@ -8,13 +8,20 @@
 
 #include "llvm/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizer.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/SandboxIR/PassManager.h"
 #include "llvm/SandboxIR/SandboxIR.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/BottomUpVec.h"
 
 using namespace llvm;
 
 #define SV_NAME "sandbox-vectorizer"
 #define DEBUG_TYPE SV_NAME
 
+cl::opt<bool>
+    PrintPassPipeline("sbvec-print-pass-pipeline", cl::init(false), cl::Hidden,
+                      cl::desc("Prints the pass pipeline and returns."));
+
 PreservedAnalyses SandboxVectorizerPass::run(Function &F,
                                              FunctionAnalysisManager &AM) {
   TTI = &AM.getResult<TargetIRAnalysis>(F);
@@ -44,8 +51,22 @@ bool SandboxVectorizerPass::runImpl(Function &LLVMF) {
   sandboxir::Context Ctx(LLVMF.getContext());
   // Create SandboxIR for `LLVMF`.
   sandboxir::Function &F = *Ctx.createFunction(&LLVMF);
-  // TODO: Initialize SBVec Pass Manager
-  (void)F;
+  // Create the passes and register them with the PassRegistry.
+  sandboxir::PassRegistry PR;
+  auto &PM = static_cast<sandboxir::FunctionPassManager &>(
+      PR.registerPass(std::make_unique<sandboxir::FunctionPassManager>("pm")));
+  auto &BottomUpVecPass = static_cast<sandboxir::FunctionPass &>(
+      PR.registerPass(std::make_unique<sandboxir::BottomUpVec>()));
+
+  // Create the default pass pipeline.
+  PM.addPass(&BottomUpVecPass);
+
+  if (PrintPassPipeline) {
+    PM.printPipeline(outs());
+    return false;
+  }
 
-  return false;
+  // Run the pass pipeline.
+  bool Change = PM.runOnFunction(F);
+  return Change;
 }

llvm/test/Transforms/SandboxVectorizer/default_pass_pipeline.ll

@@ -0,0 +1,11 @@
+; RUN: opt -passes=sandbox-vectorizer -sbvec-print-pass-pipeline %s -disable-output | FileCheck %s
+
+; !!!WARNING!!! This won't get updated by update_test_checks.py !
+
+; This checks the default pass pipeline for the sandbox vectorizer.
+define void @pipeline() {
+; CHECK: pm
+; CHECK: bottom-up-vec
+; CHECK-EMPTY:
+  ret void
+}