Use the space freed up by sparc and zaurus to import LLVM.

ok hackroom@

1 files changed, 131 insertions, 333 deletions

diff --git a/gnu/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/gnu/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 5fec51c095d..4521640e394 100644
--- a/gnu/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/gnu/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -11,12 +11,6 @@
 // non-loop form.  In cases that this kicks in, it can be a significant
 // performance win.
 //
-// If compiling for code size we avoid idiom recognition if the resulting
-// code could be larger than the code for the original loop. One way this could
-// happen is if the loop is not removable after idiom recognition due to the
-// presence of non-idiom instructions. The initial implementation of the
-// heuristics applies to idioms in multi-block loops.
-//
 //===----------------------------------------------------------------------===//
 //
 // TODO List:
@@ -32,19 +26,21 @@
 // i64 and larger types when i64 is legal and the value has few bits set.  It
 // would be good to enhance isel to emit a loop for ctpop in this case.
 //
+// We should enhance the memset/memcpy recognition to handle multiple stores in
+// the loop.  This would handle things like:
+//   void foo(_Complex float *P)
+//     for (i) { __real__(*P) = 0;  __imag__(*P) = 0; }
+//
 // This could recognize common matrix multiplies and dot product idioms and
 // replace them with calls to BLAS (if linked in??).
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar/LoopIdiomRecognize.h"
-#include "llvm/ADT/MapVector.h"
-#include "llvm/ADT/SetVector.h"
+#include "llvm/Transforms/Scalar.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/BasicAliasAnalysis.h"
 #include "llvm/Analysis/GlobalsModRef.h"
-#include "llvm/Analysis/LoopAccessAnalysis.h"
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
 #include "llvm/Analysis/ScalarEvolutionExpander.h"
@@ -59,11 +55,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Transforms/Scalar/LoopPassManager.h"
-#include "llvm/Transforms/Utils/BuildLibCalls.h"
 #include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Utils/LoopUtils.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "loop-idiom"
@@ -71,15 +63,9 @@ using namespace llvm;
 STATISTIC(NumMemSet, "Number of memset's formed from loop stores");
 STATISTIC(NumMemCpy, "Number of memcpy's formed from loop load+stores");
 
-static cl::opt<bool> UseLIRCodeSizeHeurs(
-    "use-lir-code-size-heurs",
-    cl::desc("Use loop idiom recognition code size heuristics when compiling"
-             "with -Os/-Oz"),
-    cl::init(true), cl::Hidden);
-
 namespace {
 
-class LoopIdiomRecognize {
+class LoopIdiomRecognize : public LoopPass {
   Loop *CurLoop;
   AliasAnalysis *AA;
   DominatorTree *DT;
@@ -88,24 +74,41 @@ class LoopIdiomRecognize {
   TargetLibraryInfo *TLI;
   const TargetTransformInfo *TTI;
   const DataLayout *DL;
-  bool ApplyCodeSizeHeuristics;
 
 public:
-  explicit LoopIdiomRecognize(AliasAnalysis *AA, DominatorTree *DT,
-                              LoopInfo *LI, ScalarEvolution *SE,
-                              TargetLibraryInfo *TLI,
-                              const TargetTransformInfo *TTI,
-                              const DataLayout *DL)
-      : CurLoop(nullptr), AA(AA), DT(DT), LI(LI), SE(SE), TLI(TLI), TTI(TTI),
-        DL(DL) {}
+  static char ID;
+  explicit LoopIdiomRecognize() : LoopPass(ID) {
+    initializeLoopIdiomRecognizePass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnLoop(Loop *L, LPPassManager &LPM) override;
 
-  bool runOnLoop(Loop *L);
+  /// This transformation requires natural loop information & requires that
+  /// loop preheaders be inserted into the CFG.
+  ///
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<LoopInfoWrapperPass>();
+    AU.addPreserved<LoopInfoWrapperPass>();
+    AU.addRequiredID(LoopSimplifyID);
+    AU.addPreservedID(LoopSimplifyID);
+    AU.addRequiredID(LCSSAID);
+    AU.addPreservedID(LCSSAID);
+    AU.addRequired<AAResultsWrapperPass>();
+    AU.addPreserved<AAResultsWrapperPass>();
+    AU.addRequired<ScalarEvolutionWrapperPass>();
+    AU.addPreserved<ScalarEvolutionWrapperPass>();
+    AU.addPreserved<SCEVAAWrapperPass>();
+    AU.addRequired<DominatorTreeWrapperPass>();
+    AU.addPreserved<DominatorTreeWrapperPass>();
+    AU.addRequired<TargetLibraryInfoWrapperPass>();
+    AU.addRequired<TargetTransformInfoWrapperPass>();
+    AU.addPreserved<BasicAAWrapperPass>();
+    AU.addPreserved<GlobalsAAWrapperPass>();
+  }
 
 private:
   typedef SmallVector<StoreInst *, 8> StoreList;
-  typedef MapVector<Value *, StoreList> StoreListMap;
-  StoreListMap StoreRefsForMemset;
-  StoreListMap StoreRefsForMemsetPattern;
+  StoreList StoreRefsForMemset;
   StoreList StoreRefsForMemcpy;
   bool HasMemset;
   bool HasMemsetPattern;
@@ -119,21 +122,15 @@ private:
                       SmallVectorImpl<BasicBlock *> &ExitBlocks);
 
   void collectStores(BasicBlock *BB);
-  bool isLegalStore(StoreInst *SI, bool &ForMemset, bool &ForMemsetPattern,
-                    bool &ForMemcpy);
-  bool processLoopStores(SmallVectorImpl<StoreInst *> &SL, const SCEV *BECount,
-                         bool ForMemset);
+  bool isLegalStore(StoreInst *SI, bool &ForMemset, bool &ForMemcpy);
+  bool processLoopStore(StoreInst *SI, const SCEV *BECount);
   bool processLoopMemSet(MemSetInst *MSI, const SCEV *BECount);
 
   bool processLoopStridedStore(Value *DestPtr, unsigned StoreSize,
                                unsigned StoreAlignment, Value *StoredVal,
-                               Instruction *TheStore,
-                               SmallPtrSetImpl<Instruction *> &Stores,
-                               const SCEVAddRecExpr *Ev, const SCEV *BECount,
-                               bool NegStride, bool IsLoopMemset = false);
+                               Instruction *TheStore, const SCEVAddRecExpr *Ev,
+                               const SCEV *BECount, bool NegStride);
   bool processLoopStoreOfLoopLoad(StoreInst *SI, const SCEV *BECount);
-  bool avoidLIRForMultiBlockLoop(bool IsMemset = false,
-                                 bool IsLoopMemset = false);
 
   /// @}
   /// \name Noncountable Loop Idiom Handling
@@ -148,70 +145,38 @@ private:
   /// @}
 };
 
-class LoopIdiomRecognizeLegacyPass : public LoopPass {
-public:
-  static char ID;
-  explicit LoopIdiomRecognizeLegacyPass() : LoopPass(ID) {
-    initializeLoopIdiomRecognizeLegacyPassPass(
-        *PassRegistry::getPassRegistry());
-  }
-
-  bool runOnLoop(Loop *L, LPPassManager &LPM) override {
-    if (skipLoop(L))
-      return false;
-
-    AliasAnalysis *AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
-    DominatorTree *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-    LoopInfo *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-    ScalarEvolution *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
-    TargetLibraryInfo *TLI =
-        &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
-    const TargetTransformInfo *TTI =
-        &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(
-            *L->getHeader()->getParent());
-    const DataLayout *DL = &L->getHeader()->getModule()->getDataLayout();
-
-    LoopIdiomRecognize LIR(AA, DT, LI, SE, TLI, TTI, DL);
-    return LIR.runOnLoop(L);
-  }
-
-  /// This transformation requires natural loop information & requires that
-  /// loop preheaders be inserted into the CFG.
-  ///
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<TargetLibraryInfoWrapperPass>();
-    AU.addRequired<TargetTransformInfoWrapperPass>();
-    getLoopAnalysisUsage(AU);
-  }
-};
 } // End anonymous namespace.
 
-PreservedAnalyses LoopIdiomRecognizePass::run(Loop &L, LoopAnalysisManager &AM,
-                                              LoopStandardAnalysisResults &AR,
-                                              LPMUpdater &) {
-  const auto *DL = &L.getHeader()->getModule()->getDataLayout();
-
-  LoopIdiomRecognize LIR(&AR.AA, &AR.DT, &AR.LI, &AR.SE, &AR.TLI, &AR.TTI, DL);
-  if (!LIR.runOnLoop(&L))
-    return PreservedAnalyses::all();
-
-  return getLoopPassPreservedAnalyses();
-}
-
-char LoopIdiomRecognizeLegacyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(LoopIdiomRecognizeLegacyPass, "loop-idiom",
-                      "Recognize loop idioms", false, false)
-INITIALIZE_PASS_DEPENDENCY(LoopPass)
+char LoopIdiomRecognize::ID = 0;
+INITIALIZE_PASS_BEGIN(LoopIdiomRecognize, "loop-idiom", "Recognize loop idioms",
+                      false, false)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
+INITIALIZE_PASS_DEPENDENCY(LCSSA)
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(BasicAAWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
-INITIALIZE_PASS_END(LoopIdiomRecognizeLegacyPass, "loop-idiom",
-                    "Recognize loop idioms", false, false)
+INITIALIZE_PASS_END(LoopIdiomRecognize, "loop-idiom", "Recognize loop idioms",
+                    false, false)
 
-Pass *llvm::createLoopIdiomPass() { return new LoopIdiomRecognizeLegacyPass(); }
+Pass *llvm::createLoopIdiomPass() { return new LoopIdiomRecognize(); }
 
-static void deleteDeadInstruction(Instruction *I) {
+/// deleteDeadInstruction - Delete this instruction.  Before we do, go through
+/// and zero out all the operands of this instruction.  If any of them become
+/// dead, delete them and the computation tree that feeds them.
+///
+static void deleteDeadInstruction(Instruction *I,
+                                  const TargetLibraryInfo *TLI) {
+  SmallVector<Value *, 16> Operands(I->value_op_begin(), I->value_op_end());
   I->replaceAllUsesWith(UndefValue::get(I->getType()));
   I->eraseFromParent();
+  for (Value *Op : Operands)
+    RecursivelyDeleteTriviallyDeadInstructions(Op, TLI);
 }
 
 //===----------------------------------------------------------------------===//
@@ -220,7 +185,10 @@ static void deleteDeadInstruction(Instruction *I) {
 //
 //===----------------------------------------------------------------------===//
 
-bool LoopIdiomRecognize::runOnLoop(Loop *L) {
+bool LoopIdiomRecognize::runOnLoop(Loop *L, LPPassManager &LPM) {
+  if (skipOptnoneFunction(L))
+    return false;
+
   CurLoop = L;
   // If the loop could not be converted to canonical form, it must have an
   // indirectbr in it, just give up.
@@ -232,9 +200,14 @@ bool LoopIdiomRecognize::runOnLoop(Loop *L) {
   if (Name == "memset" || Name == "memcpy")
     return false;
 
-  // Determine if code size heuristics need to be applied.
-  ApplyCodeSizeHeuristics =
-      L->getHeader()->getParent()->optForSize() && UseLIRCodeSizeHeurs;
+  AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
+  DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+  SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
+  TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+  TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(
+      *CurLoop->getHeader()->getParent());
+  DL = &CurLoop->getHeader()->getModule()->getDataLayout();
 
   HasMemset = TLI->has(LibFunc::memset);
   HasMemsetPattern = TLI->has(LibFunc::memset_pattern16);
@@ -267,14 +240,6 @@ bool LoopIdiomRecognize::runOnCountableLoop() {
                << CurLoop->getHeader()->getName() << "\n");
 
   bool MadeChange = false;
-
-  // The following transforms hoist stores/memsets into the loop pre-header.
-  // Give up if the loop has instructions may throw.
-  LoopSafetyInfo SafetyInfo;
-  computeLoopSafetyInfo(&SafetyInfo, CurLoop);
-  if (SafetyInfo.MayThrow)
-    return MadeChange;
-
   // Scan all the blocks in the loop that are not in subloops.
   for (auto *BB : CurLoop->getBlocks()) {
     // Ignore blocks in subloops.
@@ -293,9 +258,9 @@ static unsigned getStoreSizeInBytes(StoreInst *SI, const DataLayout *DL) {
   return (unsigned)SizeInBits >> 3;
 }
 
-static APInt getStoreStride(const SCEVAddRecExpr *StoreEv) {
+static unsigned getStoreStride(const SCEVAddRecExpr *StoreEv) {
   const SCEVConstant *ConstStride = cast<SCEVConstant>(StoreEv->getOperand(1));
-  return ConstStride->getAPInt();
+  return ConstStride->getAPInt().getZExtValue();
 }
 
 /// getMemSetPatternValue - If a strided store of the specified value is safe to
@@ -340,15 +305,11 @@ static Constant *getMemSetPatternValue(Value *V, const DataLayout *DL) {
 }
 
 bool LoopIdiomRecognize::isLegalStore(StoreInst *SI, bool &ForMemset,
-                                      bool &ForMemsetPattern, bool &ForMemcpy) {
+                                      bool &ForMemcpy) {
   // Don't touch volatile stores.
   if (!SI->isSimple())
     return false;
 
-  // Avoid merging nontemporal stores.
-  if (SI->getMetadata(LLVMContext::MD_nontemporal))
-    return false;
-
   Value *StoredVal = SI->getValueOperand();
   Value *StorePtr = SI->getPointerOperand();
 
@@ -392,7 +353,7 @@ bool LoopIdiomRecognize::isLegalStore(StoreInst *SI, bool &ForMemset,
              StorePtr->getType()->getPointerAddressSpace() == 0 &&
              (PatternValue = getMemSetPatternValue(StoredVal, DL))) {
     // It looks like we can use PatternValue!
-    ForMemsetPattern = true;
+    ForMemset = true;
     return true;
   }
 
@@ -400,7 +361,7 @@ bool LoopIdiomRecognize::isLegalStore(StoreInst *SI, bool &ForMemset,
   if (HasMemcpy) {
     // Check to see if the stride matches the size of the store.  If so, then we
     // know that every byte is touched in the loop.
-    APInt Stride = getStoreStride(StoreEv);
+    unsigned Stride = getStoreStride(StoreEv);
     unsigned StoreSize = getStoreSizeInBytes(SI, DL);
     if (StoreSize != Stride && StoreSize != -Stride)
       return false;
@@ -432,7 +393,6 @@ bool LoopIdiomRecognize::isLegalStore(StoreInst *SI, bool &ForMemset,
 
 void LoopIdiomRecognize::collectStores(BasicBlock *BB) {
   StoreRefsForMemset.clear();
-  StoreRefsForMemsetPattern.clear();
   StoreRefsForMemcpy.clear();
   for (Instruction &I : *BB) {
     StoreInst *SI = dyn_cast<StoreInst>(&I);
@@ -440,22 +400,15 @@ void LoopIdiomRecognize::collectStores(BasicBlock *BB) {
       continue;
 
     bool ForMemset = false;
-    bool ForMemsetPattern = false;
     bool ForMemcpy = false;
     // Make sure this is a strided store with a constant stride.
-    if (!isLegalStore(SI, ForMemset, ForMemsetPattern, ForMemcpy))
+    if (!isLegalStore(SI, ForMemset, ForMemcpy))
       continue;
 
     // Save the store locations.
-    if (ForMemset) {
-      // Find the base pointer.
-      Value *Ptr = GetUnderlyingObject(SI->getPointerOperand(), *DL);
-      StoreRefsForMemset[Ptr].push_back(SI);
-    } else if (ForMemsetPattern) {
-      // Find the base pointer.
-      Value *Ptr = GetUnderlyingObject(SI->getPointerOperand(), *DL);
-      StoreRefsForMemsetPattern[Ptr].push_back(SI);
-    } else if (ForMemcpy)
+    if (ForMemset)
+      StoreRefsForMemset.push_back(SI);
+    else if (ForMemcpy)
       StoreRefsForMemcpy.push_back(SI);
   }
 }
@@ -477,14 +430,9 @@ bool LoopIdiomRecognize::runOnLoopBlock(
   // Look for store instructions, which may be optimized to memset/memcpy.
   collectStores(BB);
 
-  // Look for a single store or sets of stores with a common base, which can be
-  // optimized into a memset (memset_pattern).  The latter most commonly happens
-  // with structs and handunrolled loops.
-  for (auto &SL : StoreRefsForMemset)
-    MadeChange |= processLoopStores(SL.second, BECount, true);
-
-  for (auto &SL : StoreRefsForMemsetPattern)
-    MadeChange |= processLoopStores(SL.second, BECount, false);
+  // Look for a single store which can be optimized into a memset.
+  for (auto &SI : StoreRefsForMemset)
+    MadeChange |= processLoopStore(SI, BECount);
 
   // Optimize the store into a memcpy, if it feeds an similarly strided load.
   for (auto &SI : StoreRefsForMemcpy)
@@ -510,144 +458,26 @@ bool LoopIdiomRecognize::runOnLoopBlock(
   return MadeChange;
 }
 
-/// processLoopStores - See if this store(s) can be promoted to a memset.
-bool LoopIdiomRecognize::processLoopStores(SmallVectorImpl<StoreInst *> &SL,
-                                           const SCEV *BECount,
-                                           bool ForMemset) {
-  // Try to find consecutive stores that can be transformed into memsets.
-  SetVector<StoreInst *> Heads, Tails;
-  SmallDenseMap<StoreInst *, StoreInst *> ConsecutiveChain;
-
-  // Do a quadratic search on all of the given stores and find
-  // all of the pairs of stores that follow each other.
-  SmallVector<unsigned, 16> IndexQueue;
-  for (unsigned i = 0, e = SL.size(); i < e; ++i) {
-    assert(SL[i]->isSimple() && "Expected only non-volatile stores.");
-
-    Value *FirstStoredVal = SL[i]->getValueOperand();
-    Value *FirstStorePtr = SL[i]->getPointerOperand();
-    const SCEVAddRecExpr *FirstStoreEv =
-        cast<SCEVAddRecExpr>(SE->getSCEV(FirstStorePtr));
-    APInt FirstStride = getStoreStride(FirstStoreEv);
-    unsigned FirstStoreSize = getStoreSizeInBytes(SL[i], DL);
-
-    // See if we can optimize just this store in isolation.
-    if (FirstStride == FirstStoreSize || -FirstStride == FirstStoreSize) {
-      Heads.insert(SL[i]);
-      continue;
-    }
-
-    Value *FirstSplatValue = nullptr;
-    Constant *FirstPatternValue = nullptr;
-
-    if (ForMemset)
-      FirstSplatValue = isBytewiseValue(FirstStoredVal);
-    else
-      FirstPatternValue = getMemSetPatternValue(FirstStoredVal, DL);
-
-    assert((FirstSplatValue || FirstPatternValue) &&
-           "Expected either splat value or pattern value.");
-
-    IndexQueue.clear();
-    // If a store has multiple consecutive store candidates, search Stores
-    // array according to the sequence: from i+1 to e, then from i-1 to 0.
-    // This is because usually pairing with immediate succeeding or preceding
-    // candidate create the best chance to find memset opportunity.
-    unsigned j = 0;
-    for (j = i + 1; j < e; ++j)
-      IndexQueue.push_back(j);
-    for (j = i; j > 0; --j)
-      IndexQueue.push_back(j - 1);
-
-    for (auto &k : IndexQueue) {
-      assert(SL[k]->isSimple() && "Expected only non-volatile stores.");
-      Value *SecondStorePtr = SL[k]->getPointerOperand();
-      const SCEVAddRecExpr *SecondStoreEv =
-          cast<SCEVAddRecExpr>(SE->getSCEV(SecondStorePtr));
-      APInt SecondStride = getStoreStride(SecondStoreEv);
-
-      if (FirstStride != SecondStride)
-        continue;
-
-      Value *SecondStoredVal = SL[k]->getValueOperand();
-      Value *SecondSplatValue = nullptr;
-      Constant *SecondPatternValue = nullptr;
-
-      if (ForMemset)
-        SecondSplatValue = isBytewiseValue(SecondStoredVal);
-      else
-        SecondPatternValue = getMemSetPatternValue(SecondStoredVal, DL);
-
-      assert((SecondSplatValue || SecondPatternValue) &&
-             "Expected either splat value or pattern value.");
-
-      if (isConsecutiveAccess(SL[i], SL[k], *DL, *SE, false)) {
-        if (ForMemset) {
-          if (FirstSplatValue != SecondSplatValue)
-            continue;
-        } else {
-          if (FirstPatternValue != SecondPatternValue)
-            continue;
-        }
-        Tails.insert(SL[k]);
-        Heads.insert(SL[i]);
-        ConsecutiveChain[SL[i]] = SL[k];
-        break;
-      }
-    }
-  }
-
-  // We may run into multiple chains that merge into a single chain. We mark the
-  // stores that we transformed so that we don't visit the same store twice.
-  SmallPtrSet<Value *, 16> TransformedStores;
-  bool Changed = false;
-
-  // For stores that start but don't end a link in the chain:
-  for (SetVector<StoreInst *>::iterator it = Heads.begin(), e = Heads.end();
-       it != e; ++it) {
-    if (Tails.count(*it))
-      continue;
-
-    // We found a store instr that starts a chain. Now follow the chain and try
-    // to transform it.
-    SmallPtrSet<Instruction *, 8> AdjacentStores;
-    StoreInst *I = *it;
-
-    StoreInst *HeadStore = I;
-    unsigned StoreSize = 0;
-
-    // Collect the chain into a list.
-    while (Tails.count(I) || Heads.count(I)) {
-      if (TransformedStores.count(I))
-        break;
-      AdjacentStores.insert(I);
-
-      StoreSize += getStoreSizeInBytes(I, DL);
-      // Move to the next value in the chain.
-      I = ConsecutiveChain[I];
-    }
-
-    Value *StoredVal = HeadStore->getValueOperand();
-    Value *StorePtr = HeadStore->getPointerOperand();
-    const SCEVAddRecExpr *StoreEv = cast<SCEVAddRecExpr>(SE->getSCEV(StorePtr));
-    APInt Stride = getStoreStride(StoreEv);
+/// processLoopStore - See if this store can be promoted to a memset.
+bool LoopIdiomRecognize::processLoopStore(StoreInst *SI, const SCEV *BECount) {
+  assert(SI->isSimple() && "Expected only non-volatile stores.");
 
-    // Check to see if the stride matches the size of the stores.  If so, then
-    // we know that every byte is touched in the loop.
-    if (StoreSize != Stride && StoreSize != -Stride)
-      continue;
+  Value *StoredVal = SI->getValueOperand();
+  Value *StorePtr = SI->getPointerOperand();
 
-    bool NegStride = StoreSize == -Stride;
+  // Check to see if the stride matches the size of the store.  If so, then we
+  // know that every byte is touched in the loop.
+  const SCEVAddRecExpr *StoreEv = cast<SCEVAddRecExpr>(SE->getSCEV(StorePtr));
+  unsigned Stride = getStoreStride(StoreEv);
+  unsigned StoreSize = getStoreSizeInBytes(SI, DL);
+  if (StoreSize != Stride && StoreSize != -Stride)
+    return false;
 
-    if (processLoopStridedStore(StorePtr, StoreSize, HeadStore->getAlignment(),
-                                StoredVal, HeadStore, AdjacentStores, StoreEv,
-                                BECount, NegStride)) {
-      TransformedStores.insert(AdjacentStores.begin(), AdjacentStores.end());
-      Changed = true;
-    }
-  }
+  bool NegStride = StoreSize == -Stride;
 
-  return Changed;
+  // See if we can optimize just this store in isolation.
+  return processLoopStridedStore(StorePtr, StoreSize, SI->getAlignment(),
+                                 StoredVal, SI, StoreEv, BECount, NegStride);
 }
 
 /// processLoopMemSet - See if this memset can be promoted to a large memset.
@@ -658,7 +488,7 @@ bool LoopIdiomRecognize::processLoopMemSet(MemSetInst *MSI,
     return false;
 
   // If we're not allowed to hack on memset, we fail.
-  if (!HasMemset)
+  if (!TLI->has(LibFunc::memset))
     return false;
 
   Value *Pointer = MSI->getDest();
@@ -677,12 +507,11 @@ bool LoopIdiomRecognize::processLoopMemSet(MemSetInst *MSI,
 
   // Check to see if the stride matches the size of the memset.  If so, then we
   // know that every byte is touched in the loop.
-  const SCEVConstant *ConstStride = dyn_cast<SCEVConstant>(Ev->getOperand(1));
-  if (!ConstStride)
-    return false;
+  const SCEVConstant *Stride = dyn_cast<SCEVConstant>(Ev->getOperand(1));
 
-  APInt Stride = ConstStride->getAPInt();
-  if (SizeInBytes != Stride && SizeInBytes != -Stride)
+  // TODO: Could also handle negative stride here someday, that will require the
+  // validity check in mayLoopAccessLocation to be updated though.
+  if (!Stride || MSI->getLength() != Stride->getValue())
     return false;
 
   // Verify that the memset value is loop invariant.  If not, we can't promote
@@ -691,22 +520,18 @@ bool LoopIdiomRecognize::processLoopMemSet(MemSetInst *MSI,
   if (!SplatValue || !CurLoop->isLoopInvariant(SplatValue))
     return false;
 
-  SmallPtrSet<Instruction *, 1> MSIs;
-  MSIs.insert(MSI);
-  bool NegStride = SizeInBytes == -Stride;
   return processLoopStridedStore(Pointer, (unsigned)SizeInBytes,
-                                 MSI->getAlignment(), SplatValue, MSI, MSIs, Ev,
-                                 BECount, NegStride, /*IsLoopMemset=*/true);
+                                 MSI->getAlignment(), SplatValue, MSI, Ev,
+                                 BECount, /*NegStride=*/false);
 }
 
 /// mayLoopAccessLocation - Return true if the specified loop might access the
 /// specified pointer location, which is a loop-strided access.  The 'Access'
 /// argument specifies what the verboten forms of access are (read or write).
-static bool
-mayLoopAccessLocation(Value *Ptr, ModRefInfo Access, Loop *L,
-                      const SCEV *BECount, unsigned StoreSize,
-                      AliasAnalysis &AA,
-                      SmallPtrSetImpl<Instruction *> &IgnoredStores) {
+static bool mayLoopAccessLocation(Value *Ptr, ModRefInfo Access, Loop *L,
+                                  const SCEV *BECount, unsigned StoreSize,
+                                  AliasAnalysis &AA,
+                                  Instruction *IgnoredStore) {
   // Get the location that may be stored across the loop.  Since the access is
   // strided positively through memory, we say that the modified location starts
   // at the pointer and has infinite size.
@@ -725,9 +550,8 @@ mayLoopAccessLocation(Value *Ptr, ModRefInfo Access, Loop *L,
 
   for (Loop::block_iterator BI = L->block_begin(), E = L->block_end(); BI != E;
        ++BI)
-    for (Instruction &I : **BI)
-      if (IgnoredStores.count(&I) == 0 &&
-          (AA.getModRefInfo(&I, StoreLoc) & Access))
+    for (BasicBlock::iterator I = (*BI)->begin(), E = (*BI)->end(); I != E; ++I)
+      if (&*I != IgnoredStore && (AA.getModRefInfo(&*I, StoreLoc) & Access))
         return true;
 
   return false;
@@ -750,9 +574,8 @@ static const SCEV *getStartForNegStride(const SCEV *Start, const SCEV *BECount,
 /// transform this into a memset or memset_pattern in the loop preheader, do so.
 bool LoopIdiomRecognize::processLoopStridedStore(
     Value *DestPtr, unsigned StoreSize, unsigned StoreAlignment,
-    Value *StoredVal, Instruction *TheStore,
-    SmallPtrSetImpl<Instruction *> &Stores, const SCEVAddRecExpr *Ev,
-    const SCEV *BECount, bool NegStride, bool IsLoopMemset) {
+    Value *StoredVal, Instruction *TheStore, const SCEVAddRecExpr *Ev,
+    const SCEV *BECount, bool NegStride) {
   Value *SplatValue = isBytewiseValue(StoredVal);
   Constant *PatternValue = nullptr;
 
@@ -786,16 +609,13 @@ bool LoopIdiomRecognize::processLoopStridedStore(
   Value *BasePtr =
       Expander.expandCodeFor(Start, DestInt8PtrTy, Preheader->getTerminator());
   if (mayLoopAccessLocation(BasePtr, MRI_ModRef, CurLoop, BECount, StoreSize,
-                            *AA, Stores)) {
+                            *AA, TheStore)) {
     Expander.clear();
     // If we generated new code for the base pointer, clean up.
     RecursivelyDeleteTriviallyDeadInstructions(BasePtr, TLI);
     return false;
   }
 
-  if (avoidLIRForMultiBlockLoop(/*IsMemset=*/true, IsLoopMemset))
-    return false;
-
   // Okay, everything looks good, insert the memset.
 
   // The # stored bytes is (BECount+1)*Size.  Expand the trip count out to
@@ -824,14 +644,13 @@ bool LoopIdiomRecognize::processLoopStridedStore(
     Value *MSP =
         M->getOrInsertFunction("memset_pattern16", Builder.getVoidTy(),
                                Int8PtrTy, Int8PtrTy, IntPtr, (void *)nullptr);
-    inferLibFuncAttributes(*M->getFunction("memset_pattern16"), *TLI);
 
     // Otherwise we should form a memset_pattern16.  PatternValue is known to be
     // an constant array of 16-bytes.  Plop the value into a mergable global.
     GlobalVariable *GV = new GlobalVariable(*M, PatternValue->getType(), true,
                                             GlobalValue::PrivateLinkage,
                                             PatternValue, ".memset_pattern");
-    GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global); // Ok to merge these.
+    GV->setUnnamedAddr(true); // Ok to merge these.
     GV->setAlignment(16);
     Value *PatternPtr = ConstantExpr::getBitCast(GV, Int8PtrTy);
     NewCall = Builder.CreateCall(MSP, {BasePtr, PatternPtr, NumBytes});
@@ -843,8 +662,7 @@ bool LoopIdiomRecognize::processLoopStridedStore(
 
   // Okay, the memset has been formed.  Zap the original store and anything that
   // feeds into it.
-  for (auto *I : Stores)
-    deleteDeadInstruction(I);
+  deleteDeadInstruction(TheStore, TLI);
   ++NumMemSet;
   return true;
 }
@@ -858,7 +676,7 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(StoreInst *SI,
 
   Value *StorePtr = SI->getPointerOperand();
   const SCEVAddRecExpr *StoreEv = cast<SCEVAddRecExpr>(SE->getSCEV(StorePtr));
-  APInt Stride = getStoreStride(StoreEv);
+  unsigned Stride = getStoreStride(StoreEv);
   unsigned StoreSize = getStoreSizeInBytes(SI, DL);
   bool NegStride = StoreSize == -Stride;
 
@@ -896,10 +714,8 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(StoreInst *SI,
   Value *StoreBasePtr = Expander.expandCodeFor(
       StrStart, Builder.getInt8PtrTy(StrAS), Preheader->getTerminator());
 
-  SmallPtrSet<Instruction *, 1> Stores;
-  Stores.insert(SI);
   if (mayLoopAccessLocation(StoreBasePtr, MRI_ModRef, CurLoop, BECount,
-                            StoreSize, *AA, Stores)) {
+                            StoreSize, *AA, SI)) {
     Expander.clear();
     // If we generated new code for the base pointer, clean up.
     RecursivelyDeleteTriviallyDeadInstructions(StoreBasePtr, TLI);
@@ -919,7 +735,7 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(StoreInst *SI,
       LdStart, Builder.getInt8PtrTy(LdAS), Preheader->getTerminator());
 
   if (mayLoopAccessLocation(LoadBasePtr, MRI_Mod, CurLoop, BECount, StoreSize,
-                            *AA, Stores)) {
+                            *AA, SI)) {
     Expander.clear();
     // If we generated new code for the base pointer, clean up.
     RecursivelyDeleteTriviallyDeadInstructions(LoadBasePtr, TLI);
@@ -927,9 +743,6 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(StoreInst *SI,
     return false;
   }
 
-  if (avoidLIRForMultiBlockLoop())
-    return false;
-
   // Okay, everything is safe, we can transform this!
 
   // The # stored bytes is (BECount+1)*Size.  Expand the trip count out to
@@ -956,28 +769,11 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(StoreInst *SI,
 
   // Okay, the memcpy has been formed.  Zap the original store and anything that
   // feeds into it.
-  deleteDeadInstruction(SI);
+  deleteDeadInstruction(SI, TLI);
   ++NumMemCpy;
   return true;
 }
 
-// When compiling for codesize we avoid idiom recognition for a multi-block loop
-// unless it is a loop_memset idiom or a memset/memcpy idiom in a nested loop.
-//
-bool LoopIdiomRecognize::avoidLIRForMultiBlockLoop(bool IsMemset,
-                                                   bool IsLoopMemset) {
-  if (ApplyCodeSizeHeuristics && CurLoop->getNumBlocks() > 1) {
-    if (!CurLoop->getParentLoop() && (!IsMemset || !IsLoopMemset)) {
-      DEBUG(dbgs() << "  " << CurLoop->getHeader()->getParent()->getName()
-                   << " : LIR " << (IsMemset ? "Memset" : "Memcpy")
-                   << " avoided: multi-block top-level loop\n");
-      return true;
-    }
-  }
-
-  return false;
-}
-
 bool LoopIdiomRecognize::runOnNoncountableLoop() {
   return recognizePopcount();
 }
@@ -985,7 +781,7 @@ bool LoopIdiomRecognize::runOnNoncountableLoop() {
 /// Check if the given conditional branch is based on the comparison between
 /// a variable and zero, and if the variable is non-zero, the control yields to
 /// the loop entry. If the branch matches the behavior, the variable involved
-/// in the comparison is returned. This function will be called to see if the
+/// in the comparion is returned. This function will be called to see if the
 /// precondition and postcondition of the loop are in desirable form.
 static Value *matchCondition(BranchInst *BI, BasicBlock *LoopEntry) {
   if (!BI || !BI->isConditional())
@@ -1169,7 +965,9 @@ bool LoopIdiomRecognize::recognizePopcount() {
 
   // It should have a preheader containing nothing but an unconditional branch.
   BasicBlock *PH = CurLoop->getLoopPreheader();
-  if (!PH || &PH->front() != PH->getTerminator())
+  if (!PH)
+    return false;
+  if (&PH->front() != PH->getTerminator())
     return false;
   auto *EntryBI = dyn_cast<BranchInst>(PH->getTerminator());
   if (!EntryBI || EntryBI->isConditional())
@@ -1195,7 +993,7 @@ bool LoopIdiomRecognize::recognizePopcount() {
 }
 
 static CallInst *createPopcntIntrinsic(IRBuilder<> &IRBuilder, Value *Val,
-                                       const DebugLoc &DL) {
+                                       DebugLoc DL) {
   Value *Ops[] = {Val};
   Type *Tys[] = {Val->getType()};