7 files changed, 76 insertions, 36 deletions
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 2472008548a..88a7c389233 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -65,7 +65,7 @@ void initializeTarget(PassRegistry&);
 void initializeAAEvalLegacyPassPass(PassRegistry&);
 void initializeAddDiscriminatorsPass(PassRegistry&);
 void initializeADCELegacyPassPass(PassRegistry&);
-void initializeBDCEPass(PassRegistry&);
+void initializeBDCELegacyPassPass(PassRegistry &);
 void initializeAliasSetPrinterPass(PassRegistry&);
 void initializeAlwaysInlinerPass(PassRegistry&);
 void initializeArgPromotionPass(PassRegistry&);
diff --git a/llvm/include/llvm/Transforms/Scalar/BDCE.h b/llvm/include/llvm/Transforms/Scalar/BDCE.h
new file mode 100644
index 00000000000..d7d2730a803
--- /dev/null
+++ b/llvm/include/llvm/Transforms/Scalar/BDCE.h
@@ -0,0 +1,31 @@
+//===---- BDCE.cpp - Bit-tracking dead code elimination ---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Bit-Tracking Dead Code Elimination pass. Some
+// instructions (shifts, some ands, ors, etc.) kill some of their input bits.
+// We track these dead bits and remove instructions that compute only these
+// dead bits.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_BDCE_H
+#define LLVM_TRANSFORMS_SCALAR_BDCE_H
+
+#include "llvm/IR/Function.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+// The Bit-Tracking Dead Code Elimination pass.
+struct BDCEPass : PassInfoMixin<BDCEPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+}
+
+#endif // LLVM_TRANSFORMS_SCALAR_BDCE_H
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 3c514b8e2d8..23b51cebe35 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -63,11 +63,12 @@
 #include "llvm/Transforms/InstrProfiling.h"
 #include "llvm/Transforms/PGOInstrumentation.h"
 #include "llvm/Transforms/Scalar/ADCE.h"
+#include "llvm/Transforms/Scalar/BDCE.h"
 #include "llvm/Transforms/Scalar/DCE.h"
 #include "llvm/Transforms/Scalar/DeadStoreElimination.h"
 #include "llvm/Transforms/Scalar/EarlyCSE.h"
-#include "llvm/Transforms/Scalar/GuardWidening.h"
 #include "llvm/Transforms/Scalar/GVN.h"
+#include "llvm/Transforms/Scalar/GuardWidening.h"
 #include "llvm/Transforms/Scalar/LoopRotation.h"
 #include "llvm/Transforms/Scalar/LoopSimplifyCFG.h"
 #include "llvm/Transforms/Scalar/LowerAtomic.h"
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index d517f646b2a..5d74d7108d9 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -110,6 +110,7 @@ FUNCTION_ALIAS_ANALYSIS("type-based-aa", TypeBasedAA())
 #endif
 FUNCTION_PASS("aa-eval", AAEvaluator())
 FUNCTION_PASS("adce", ADCEPass())
+FUNCTION_PASS("bdce", BDCEPass())
 FUNCTION_PASS("dce", DCEPass())
 FUNCTION_PASS("dse", DSEPass())
 FUNCTION_PASS("early-cse", EarlyCSEPass())
diff --git a/llvm/lib/Transforms/Scalar/BDCE.cpp b/llvm/lib/Transforms/Scalar/BDCE.cpp
index a357280dcef..a1331ddf44a 100644
--- a/llvm/lib/Transforms/Scalar/BDCE.cpp
+++ b/llvm/lib/Transforms/Scalar/BDCE.cpp
@@ -14,11 +14,11 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/BDCE.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/DemandedBits.h"
+#include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instructions.h"
@@ -27,6 +27,7 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "bdce"
@@ -34,35 +35,7 @@ using namespace llvm;
 STATISTIC(NumRemoved, "Number of instructions removed (unused)");
 STATISTIC(NumSimplified, "Number of instructions trivialized (dead bits)");
 
-namespace {
-struct BDCE : public FunctionPass {
-  static char ID; // Pass identification, replacement for typeid
-  BDCE() : FunctionPass(ID) {
-    initializeBDCEPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function& F) override;
-
-  void getAnalysisUsage(AnalysisUsage& AU) const override {
-    AU.setPreservesCFG();
-    AU.addRequired<DemandedBitsWrapperPass>();
-    AU.addPreserved<GlobalsAAWrapperPass>();
-  }
-};
-}
-
-char BDCE::ID = 0;
-INITIALIZE_PASS_BEGIN(BDCE, "bdce", "Bit-Tracking Dead Code Elimination",
-                      false, false)
-INITIALIZE_PASS_DEPENDENCY(DemandedBitsWrapperPass)
-INITIALIZE_PASS_END(BDCE, "bdce", "Bit-Tracking Dead Code Elimination",
-                    false, false)
-
-bool BDCE::runOnFunction(Function& F) {
-  if (skipFunction(F))
-    return false;
-  auto &DB = getAnalysis<DemandedBitsWrapperPass>().getDemandedBits();
-
+static bool bitTrackingDCE(Function &F, DemandedBits &DB) {
   SmallVector<Instruction*, 128> Worklist;
   bool Changed = false;
   for (Instruction &I : instructions(F)) {
@@ -96,7 +69,40 @@ bool BDCE::runOnFunction(Function& F) {
   return Changed;
 }
 
-FunctionPass *llvm::createBitTrackingDCEPass() {
-  return new BDCE();
+PreservedAnalyses BDCEPass::run(Function &F, FunctionAnalysisManager &AM) {
+  auto &DB = AM.getResult<DemandedBitsAnalysis>(F);
+  if (bitTrackingDCE(F, DB))
+    return PreservedAnalyses::none();
+  return PreservedAnalyses::all();
 }
 
+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(); }
diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index da6244d6ce1..eb950bc8e23 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -32,7 +32,7 @@ using namespace llvm;
 /// ScalarOpts library.
 void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeADCELegacyPassPass(Registry);
-  initializeBDCEPass(Registry);
+  initializeBDCELegacyPassPass(Registry);
   initializeAlignmentFromAssumptionsPass(Registry);
   initializeConstantHoistingPass(Registry);
   initializeConstantPropagationPass(Registry);
diff --git a/llvm/test/Transforms/BDCE/dce-pure.ll b/llvm/test/Transforms/BDCE/dce-pure.ll
index a379fa4a003..a487a04db61 100644
--- a/llvm/test/Transforms/BDCE/dce-pure.ll
+++ b/llvm/test/Transforms/BDCE/dce-pure.ll
@@ -1,4 +1,5 @@
 ; RUN: opt -bdce -S < %s | FileCheck %s
+; RUN: opt -passes=bdce -S < %s | FileCheck %s
 
 declare i32 @strlen(i8*) readonly nounwind