[Passes] Remove legacy PM version of BDCE (aka BitTrackingDCEPass)

BDCE is not used by the codegen pipeline so we should not need the
legacy PM version of the pass any longer.

Differential Revision: https://reviews.llvm.org/D148335

Author: bjope

llvm/include/llvm/InitializePasses.h

@@ -62,7 +62,6 @@ void initializeAssumptionCacheTrackerPass(PassRegistry&);
 void initializeAtomicExpandPass(PassRegistry&);
 void initializeBasicBlockSectionsProfileReaderPass(PassRegistry &);
 void initializeBasicBlockSectionsPass(PassRegistry &);
-void initializeBDCELegacyPassPass(PassRegistry&);
 void initializeBarrierNoopPass(PassRegistry&);
 void initializeBasicAAWrapperPassPass(PassRegistry&);
 void initializeBlockFrequencyInfoWrapperPassPass(PassRegistry&);

llvm/include/llvm/LinkAllPasses.h

@@ -69,7 +69,6 @@ namespace {
         return;
 
       (void) llvm::createAAEvalPass();
-      (void)llvm::createBitTrackingDCEPass();
       (void) llvm::createAlignmentFromAssumptionsPass();
       (void) llvm::createBasicAAWrapperPass();
       (void) llvm::createSCEVAAWrapperPass();

llvm/include/llvm/Transforms/Scalar.h

@@ -73,13 +73,6 @@ FunctionPass *createGuardWideningPass();
 Pass *createLoopGuardWideningPass();
 
 
-//===----------------------------------------------------------------------===//
-//
-// BitTrackingDCE - This pass uses a bit-tracking DCE algorithm in order to
-// remove computations of dead bits.
-//
-FunctionPass *createBitTrackingDCEPass();
-
 //===----------------------------------------------------------------------===//
 //
 // SROA - Replace aggregates or pieces of aggregates with scalar SSA values.

llvm/lib/Transforms/Scalar/BDCE.cpp

@@ -23,11 +23,8 @@
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instructions.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Pass.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
 
@@ -173,34 +170,3 @@ PreservedAnalyses BDCEPass::run(Function &F, FunctionAnalysisManager &AM) {
   PA.preserveSet<CFGAnalyses>();
   return PA;
 }
-
-namespace {
-struct BDCELegacyPass : public FunctionPass {
-  static char ID; // Pass identification, replacement for typeid
-  BDCELegacyPass() : FunctionPass(ID) {
-    initializeBDCELegacyPassPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override {
-    if (skipFunction(F))
-      return false;
-    auto &DB = getAnalysis<DemandedBitsWrapperPass>().getDemandedBits();
-    return bitTrackingDCE(F, DB);
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.setPreservesCFG();
-    AU.addRequired<DemandedBitsWrapperPass>();
-    AU.addPreserved<GlobalsAAWrapperPass>();
-  }
-};
-}
-
-char BDCELegacyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(BDCELegacyPass, "bdce",
-                      "Bit-Tracking Dead Code Elimination", false, false)
-INITIALIZE_PASS_DEPENDENCY(DemandedBitsWrapperPass)
-INITIALIZE_PASS_END(BDCELegacyPass, "bdce",
-                    "Bit-Tracking Dead Code Elimination", false, false)
-
-FunctionPass *llvm::createBitTrackingDCEPass() { return new BDCELegacyPass(); }

llvm/lib/Transforms/Scalar/Scalar.cpp

@@ -27,7 +27,6 @@ using namespace llvm;
 /// initializeScalarOptsPasses - Initialize all passes linked into the
 /// ScalarOpts library.
 void llvm::initializeScalarOpts(PassRegistry &Registry) {
-  initializeBDCELegacyPassPass(Registry);
   initializeAlignmentFromAssumptionsPass(Registry);
   initializeCallSiteSplittingLegacyPassPass(Registry);
   initializeConstantHoistingLegacyPassPass(Registry);