[llvm] [NewPM] Remove LoopGuardWideningLegacyPass (PR #72937)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/72937

This pass isn't used/tested upstream at all, so remove it.

>From 240907f8faae3f4ac56ced37fb2f3a9818bb2633 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <agrossman154 at yahoo.com>
Date: Mon, 20 Nov 2023 17:34:00 -0800
Subject: [PATCH] [NewPM] Remove LoopGuardWideningLegacyPass

This pass isn't used/tested upstream at all, so remove it.
---
 llvm/include/llvm/InitializePasses.h         |  1 -
 llvm/include/llvm/LinkAllPasses.h            |  1 -
 llvm/include/llvm/Transforms/Scalar.h        | 10 ----
 llvm/lib/Transforms/Scalar/GuardWidening.cpp | 63 --------------------
 llvm/lib/Transforms/Scalar/Scalar.cpp        |  1 -
 5 files changed, 76 deletions(-)

diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 2305db4f775d49c..eff6222abd704de 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -172,7 +172,6 @@ void initializeLocalStackSlotPassPass(PassRegistry&);
 void initializeLocalizerPass(PassRegistry&);
 void initializeLoopDataPrefetchLegacyPassPass(PassRegistry&);
 void initializeLoopExtractorLegacyPassPass(PassRegistry &);
-void initializeLoopGuardWideningLegacyPassPass(PassRegistry&);
 void initializeLoopInfoWrapperPassPass(PassRegistry&);
 void initializeLoopPassPass(PassRegistry&);
 void initializeLoopPredicationLegacyPassPass(PassRegistry&);
diff --git a/llvm/include/llvm/LinkAllPasses.h b/llvm/include/llvm/LinkAllPasses.h
index 0d15481034151df..9585a32ec230a6f 100644
--- a/llvm/include/llvm/LinkAllPasses.h
+++ b/llvm/include/llvm/LinkAllPasses.h
@@ -79,7 +79,6 @@ namespace {
       (void) llvm::createDomViewerWrapperPassPass();
       (void) llvm::createAlwaysInlinerLegacyPass();
       (void) llvm::createGlobalsAAWrapperPass();
-      (void) llvm::createLoopGuardWideningPass();
       (void) llvm::createInstSimplifyLegacyPass();
       (void) llvm::createInstructionCombiningPass();
       (void) llvm::createJMCInstrumenterPass();
diff --git a/llvm/include/llvm/Transforms/Scalar.h b/llvm/include/llvm/Transforms/Scalar.h
index 111e5446603d26b..1ee1fb34cddfaf0 100644
--- a/llvm/include/llvm/Transforms/Scalar.h
+++ b/llvm/include/llvm/Transforms/Scalar.h
@@ -39,16 +39,6 @@ Pass *createRedundantDbgInstEliminationPass();
 //
 FunctionPass *createDeadCodeEliminationPass();
 
-//===----------------------------------------------------------------------===//
-//
-// LoopGuardWidening - Analogous to the GuardWidening pass, but restricted to a
-// single loop at a time for use within a LoopPassManager.  Desired effect is
-// to widen guards into preheader or a single guard within loop if that's not
-// possible.
-//
-Pass *createLoopGuardWideningPass();
-
-
 //===----------------------------------------------------------------------===//
 //
 // SROA - Replace aggregates or pieces of aggregates with scalar SSA values.
diff --git a/llvm/lib/Transforms/Scalar/GuardWidening.cpp b/llvm/lib/Transforms/Scalar/GuardWidening.cpp
index 0dd99f45f670d13..5506dd82efd4557 100644
--- a/llvm/lib/Transforms/Scalar/GuardWidening.cpp
+++ b/llvm/lib/Transforms/Scalar/GuardWidening.cpp
@@ -45,7 +45,6 @@
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/GuardUtils.h"
 #include "llvm/Analysis/LoopInfo.h"
-#include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/MemorySSAUpdater.h"
 #include "llvm/Analysis/PostDominators.h"
 #include "llvm/Analysis/ValueTracking.h"
@@ -54,8 +53,6 @@
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/PatternMatch.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/KnownBits.h"
@@ -1013,63 +1010,3 @@ PreservedAnalyses GuardWideningPass::run(Loop &L, LoopAnalysisManager &AM,
     PA.preserve<MemorySSAAnalysis>();
   return PA;
 }
-
-namespace {
-/// Restricted to a single loop at a time.  Can be
-/// scheduled with other loop passes w/o breaking out of LPM
-struct LoopGuardWideningLegacyPass : public LoopPass {
-  static char ID;
-
-  LoopGuardWideningLegacyPass() : LoopPass(ID) {
-    initializeLoopGuardWideningLegacyPassPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnLoop(Loop *L, LPPassManager &LPM) override {
-    if (skipLoop(L))
-      return false;
-    auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-    auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-    auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(
-        *L->getHeader()->getParent());
-    auto *PDTWP = getAnalysisIfAvailable<PostDominatorTreeWrapperPass>();
-    auto *PDT = PDTWP ? &PDTWP->getPostDomTree() : nullptr;
-    auto *MSSAWP = getAnalysisIfAvailable<MemorySSAWrapperPass>();
-    std::unique_ptr<MemorySSAUpdater> MSSAU;
-    if (MSSAWP)
-      MSSAU = std::make_unique<MemorySSAUpdater>(&MSSAWP->getMSSA());
-
-    BasicBlock *RootBB = L->getLoopPredecessor();
-    if (!RootBB)
-      RootBB = L->getHeader();
-    auto BlockFilter = [&](BasicBlock *BB) {
-      return BB == RootBB || L->contains(BB);
-    };
-    return GuardWideningImpl(DT, PDT, LI, AC, MSSAU ? MSSAU.get() : nullptr,
-                             DT.getNode(RootBB), BlockFilter)
-        .run();
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.setPreservesCFG();
-    getLoopAnalysisUsage(AU);
-    AU.addPreserved<PostDominatorTreeWrapperPass>();
-    AU.addPreserved<MemorySSAWrapperPass>();
-  }
-};
-}
-
-char LoopGuardWideningLegacyPass::ID = 0;
-
-INITIALIZE_PASS_BEGIN(LoopGuardWideningLegacyPass, "loop-guard-widening",
-                      "Widen guards (within a single loop, as a loop pass)",
-                      false, false)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
-INITIALIZE_PASS_END(LoopGuardWideningLegacyPass, "loop-guard-widening",
-                    "Widen guards (within a single loop, as a loop pass)",
-                    false, false)
-
-Pass *llvm::createLoopGuardWideningPass() {
-  return new LoopGuardWideningLegacyPass();
-}
diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index 80db06b03a901b3..4df270bcf0b83fb 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -21,7 +21,6 @@ using namespace llvm;
 void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeConstantHoistingLegacyPassPass(Registry);
   initializeDCELegacyPassPass(Registry);
-  initializeLoopGuardWideningLegacyPassPass(Registry);
   initializeGVNLegacyPassPass(Registry);
   initializeEarlyCSELegacyPassPass(Registry);
   initializeEarlyCSEMemSSALegacyPassPass(Registry);