[NewPM] Remove MergedLoadStoreMotionLegacyPass (#72813)

This pass isn't used anywhere and thus isn't tested anywhere. Because of
these reasons, remove it.

Author: boomanaiden154

llvm/include/llvm/InitializePasses.h

@@ -228,7 +228,6 @@ void initializeMachineVerifierPassPass(PassRegistry&);
 void initializeMemoryDependenceWrapperPassPass(PassRegistry&);
 void initializeMemorySSAWrapperPassPass(PassRegistry&);
 void initializeMergeICmpsLegacyPassPass(PassRegistry &);
-void initializeMergedLoadStoreMotionLegacyPassPass(PassRegistry&);
 void initializeModuleSummaryIndexWrapperPassPass(PassRegistry&);
 void initializeModuloScheduleTestPass(PassRegistry&);
 void initializeNaryReassociateLegacyPassPass(PassRegistry&);

llvm/include/llvm/LinkAllPasses.h

@@ -124,7 +124,6 @@ namespace {
       (void) llvm::createConstantHoistingPass();
       (void) llvm::createCodeGenPreparePass();
       (void) llvm::createEarlyCSEPass();
-      (void) llvm::createMergedLoadStoreMotionPass();
       (void) llvm::createGVNPass();
       (void) llvm::createPostDomTree();
       (void) llvm::createMergeICmpsLegacyPass();

llvm/include/llvm/Transforms/Scalar.h

@@ -147,13 +147,6 @@ FunctionPass *createTailCallEliminationPass();
 //
 FunctionPass *createEarlyCSEPass(bool UseMemorySSA = false);
 
-//===----------------------------------------------------------------------===//
-//
-// MergedLoadStoreMotion - This pass merges loads and stores in diamonds. Loads
-// are hoisted into the header, while stores sink into the footer.
-//
-FunctionPass *createMergedLoadStoreMotionPass(bool SplitFooterBB = false);
-
 //===----------------------------------------------------------------------===//
 //
 // ConstantHoisting - This pass prepares a function for expensive constants.

llvm/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp

@@ -80,7 +80,6 @@
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
-#include "llvm/InitializePasses.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Scalar.h"
@@ -378,52 +377,6 @@ bool MergedLoadStoreMotion::run(Function &F, AliasAnalysis &AA) {
   return Changed;
 }
 
-namespace {
-class MergedLoadStoreMotionLegacyPass : public FunctionPass {
-  const bool SplitFooterBB;
-public:
-  static char ID; // Pass identification, replacement for typeid
-  MergedLoadStoreMotionLegacyPass(bool SplitFooterBB = false)
-      : FunctionPass(ID), SplitFooterBB(SplitFooterBB) {
-    initializeMergedLoadStoreMotionLegacyPassPass(
-        *PassRegistry::getPassRegistry());
-  }
-
-  ///
-  /// Run the transformation for each function
-  ///
-  bool runOnFunction(Function &F) override {
-    if (skipFunction(F))
-      return false;
-    MergedLoadStoreMotion Impl(SplitFooterBB);
-    return Impl.run(F, getAnalysis<AAResultsWrapperPass>().getAAResults());
-  }
-
-private:
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    if (!SplitFooterBB)
-      AU.setPreservesCFG();
-    AU.addRequired<AAResultsWrapperPass>();
-    AU.addPreserved<GlobalsAAWrapperPass>();
-  }
-};
-
-char MergedLoadStoreMotionLegacyPass::ID = 0;
-} // anonymous namespace
-
-///
-/// createMergedLoadStoreMotionPass - The public interface to this file.
-///
-FunctionPass *llvm::createMergedLoadStoreMotionPass(bool SplitFooterBB) {
-  return new MergedLoadStoreMotionLegacyPass(SplitFooterBB);
-}
-
-INITIALIZE_PASS_BEGIN(MergedLoadStoreMotionLegacyPass, "mldst-motion",
-                      "MergedLoadStoreMotion", false, false)
-INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
-INITIALIZE_PASS_END(MergedLoadStoreMotionLegacyPass, "mldst-motion",
-                    "MergedLoadStoreMotion", false, false)
-
 PreservedAnalyses
 MergedLoadStoreMotionPass::run(Function &F, FunctionAnalysisManager &AM) {
   MergedLoadStoreMotion Impl(Options.SplitFooterBB);

llvm/lib/Transforms/Scalar/Scalar.cpp

@@ -40,7 +40,6 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeLowerConstantIntrinsicsPass(Registry);
   initializeLowerWidenableConditionLegacyPassPass(Registry);
   initializeMergeICmpsLegacyPassPass(Registry);
-  initializeMergedLoadStoreMotionLegacyPassPass(Registry);
   initializeNaryReassociateLegacyPassPass(Registry);
   initializePartiallyInlineLibCallsLegacyPassPass(Registry);
   initializeReassociateLegacyPassPass(Registry);