From eb5530e621aafedeecafcc25594a6492c0a1e6c3 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i@maskray.me>
Date: Tue, 14 Feb 2023 15:51:09 -0800
Subject: [PATCH] [LoopDistribute] Remove legacy pass

Following recent changes to remove non-core features of the legacy PM/optimization pipeline.
---
 llvm/include/llvm/InitializePasses.h          |  1 -
 llvm/include/llvm/Transforms/Scalar.h         |  6 ---
 .../lib/Transforms/IPO/PassManagerBuilder.cpp |  6 ---
 llvm/lib/Transforms/Scalar/LoopDistribute.cpp | 54 -------------------
 llvm/lib/Transforms/Scalar/Scalar.cpp         |  1 -
 5 files changed, 68 deletions(-)

diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 8fa9e1e2948d..e0c1f49893e4 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -207,7 +207,6 @@ void initializeLocalizerPass(PassRegistry&);
 void initializeLoopAccessLegacyAnalysisPass(PassRegistry&);
 void initializeLoopDataPrefetchLegacyPassPass(PassRegistry&);
 void initializeLoopDeletionLegacyPassPass(PassRegistry&);
-void initializeLoopDistributeLegacyPass(PassRegistry&);
 void initializeLoopExtractorLegacyPassPass(PassRegistry &);
 void initializeLoopGuardWideningLegacyPassPass(PassRegistry&);
 void initializeLoopFuseLegacyPass(PassRegistry&);
diff --git a/llvm/include/llvm/Transforms/Scalar.h b/llvm/include/llvm/Transforms/Scalar.h
index 8fbe14293114..7bac07f2f1ba 100644
--- a/llvm/include/llvm/Transforms/Scalar.h
+++ b/llvm/include/llvm/Transforms/Scalar.h
@@ -478,12 +478,6 @@ FunctionPass *createFloat2IntPass();
 //
 FunctionPass *createNaryReassociatePass();
 
-//===----------------------------------------------------------------------===//
-//
-// LoopDistribute - Distribute loops.
-//
-FunctionPass *createLoopDistributePass();
-
 //===----------------------------------------------------------------------===//
 //
 // LoopFuse - Fuse loops.
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 893cca50efc4..42849e940409 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -389,12 +389,6 @@ void PassManagerBuilder::populateModulePassManager(
   // on the rotated form. Disable header duplication at -Oz.
   MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1, false));
 
-  // Distribute loops to allow partial vectorization.  I.e. isolate dependences
-  // into separate loop that would otherwise inhibit vectorization.  This is
-  // currently only performed for loops marked with the metadata
-  // llvm.loop.distribute=true or when -enable-loop-distribute is specified.
-  MPM.add(createLoopDistributePass());
-
   addVectorPasses(MPM, /* IsFullLTO */ false);
 
   // GlobalOpt already deletes dead functions and globals, at -O2 try a
diff --git a/llvm/lib/Transforms/Scalar/LoopDistribute.cpp b/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
index 7b52b7dca85f..08c0cf789583 100644
--- a/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDistribute.cpp
@@ -995,45 +995,6 @@ static bool runImpl(Function &F, LoopInfo *LI, DominatorTree *DT,
   return Changed;
 }
 
-namespace {
-
-/// The pass class.
-class LoopDistributeLegacy : public FunctionPass {
-public:
-  static char ID;
-
-  LoopDistributeLegacy() : FunctionPass(ID) {
-    // The default is set by the caller.
-    initializeLoopDistributeLegacyPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override {
-    if (skipFunction(F))
-      return false;
-
-    auto *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-    auto *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-    auto *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
-    auto *ORE = &getAnalysis<OptimizationRemarkEmitterWrapperPass>().getORE();
-    auto &LAIs = getAnalysis<LoopAccessLegacyAnalysis>().getLAIs();
-
-    return runImpl(F, LI, DT, SE, ORE, LAIs);
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<ScalarEvolutionWrapperPass>();
-    AU.addRequired<LoopInfoWrapperPass>();
-    AU.addPreserved<LoopInfoWrapperPass>();
-    AU.addRequired<LoopAccessLegacyAnalysis>();
-    AU.addRequired<DominatorTreeWrapperPass>();
-    AU.addPreserved<DominatorTreeWrapperPass>();
-    AU.addRequired<OptimizationRemarkEmitterWrapperPass>();
-    AU.addPreserved<GlobalsAAWrapperPass>();
-  }
-};
-
-} // end anonymous namespace
-
 PreservedAnalyses LoopDistributePass::run(Function &F,
                                           FunctionAnalysisManager &AM) {
   auto &LI = AM.getResult<LoopAnalysis>(F);
@@ -1050,18 +1011,3 @@ PreservedAnalyses LoopDistributePass::run(Function &F,
   PA.preserve<DominatorTreeAnalysis>();
   return PA;
 }
-
-char LoopDistributeLegacy::ID;
-
-static const char ldist_name[] = "Loop Distribution";
-
-INITIALIZE_PASS_BEGIN(LoopDistributeLegacy, LDIST_NAME, ldist_name, false,
-                      false)
-INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(LoopAccessLegacyAnalysis)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(OptimizationRemarkEmitterWrapperPass)
-INITIALIZE_PASS_END(LoopDistributeLegacy, LDIST_NAME, ldist_name, false, false)
-
-FunctionPass *llvm::createLoopDistributePass() { return new LoopDistributeLegacy(); }
diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index e4a58b126537..11f819eb4b6e 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -104,7 +104,6 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializePlaceBackedgeSafepointsImplPass(Registry);
   initializePlaceSafepointsPass(Registry);
   initializeFloat2IntLegacyPassPass(Registry);
-  initializeLoopDistributeLegacyPass(Registry);
   initializeLoopLoadEliminationPass(Registry);
   initializeLoopSimplifyCFGLegacyPassPass(Registry);
   initializeLoopVersioningLegacyPassPass(Registry);
-- 
2.34.1