//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "loop-idiom"
#include "llvm/Transforms/Scalar.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
+#define DEBUG_TYPE "loop-idiom"
+
STATISTIC(NumMemSet, "Number of memset's formed from loop stores");
STATISTIC(NumMemCpy, "Number of memcpy's formed from loop load+stores");
return dyn_cast<BranchInst>(BB->getTerminator());
}
- /// Return the condition of the branch terminating the given basic block.
- static Value *getBrCondtion(BasicBlock *);
-
/// Derive the precondition block (i.e the block that guards the loop
/// preheader) from the given preheader.
static BasicBlock *getPrecondBb(BasicBlock *PreHead);
/// the variable involved in the comparion is returned. This function will
/// be called to see if the precondition and postcondition of the loop
/// are in desirable form.
- Value *matchCondition (BranchInst *Br, BasicBlock *NonZeroTarget) const;
+ Value *matchCondition(BranchInst *Br, BasicBlock *NonZeroTarget) const;
/// Return true iff the idiom is detected in the loop. and 1) \p CntInst
- /// is set to the instruction counting the pupulation bit. 2) \p CntPhi
+ /// is set to the instruction counting the population bit. 2) \p CntPhi
/// is set to the corresponding phi node. 3) \p Var is set to the value
/// whose population bits are being counted.
bool detectIdiom
(Instruction *&CntInst, PHINode *&CntPhi, Value *&Var) const;
/// Insert ctpop intrinsic function and some obviously dead instructions.
- void transform (Instruction *CntInst, PHINode *CntPhi, Value *Var);
+ void transform(Instruction *CntInst, PHINode *CntPhi, Value *Var);
/// Create llvm.ctpop.* intrinsic function.
CallInst *createPopcntIntrinsic(IRBuilderTy &IRB, Value *Val, DebugLoc DL);
class LoopIdiomRecognize : public LoopPass {
Loop *CurLoop;
- const DataLayout *DL;
DominatorTree *DT;
ScalarEvolution *SE;
TargetLibraryInfo *TLI;
static char ID;
explicit LoopIdiomRecognize() : LoopPass(ID) {
initializeLoopIdiomRecognizePass(*PassRegistry::getPassRegistry());
- DL = 0; DT = 0; SE = 0; TLI = 0; TTI = 0;
+ DT = nullptr;
+ SE = nullptr;
+ TLI = nullptr;
+ TTI = nullptr;
}
bool runOnLoop(Loop *L, LPPassManager &LPM) override;
/// loop preheaders be inserted into the CFG.
///
void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.addRequired<LoopInfo>();
- AU.addPreserved<LoopInfo>();
+ AU.addRequired<LoopInfoWrapperPass>();
+ AU.addPreserved<LoopInfoWrapperPass>();
AU.addRequiredID(LoopSimplifyID);
AU.addPreservedID(LoopSimplifyID);
AU.addRequiredID(LCSSAID);
AU.addPreserved<ScalarEvolution>();
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addRequired<DominatorTreeWrapperPass>();
- AU.addRequired<TargetLibraryInfo>();
- AU.addRequired<TargetTransformInfo>();
- }
-
- const DataLayout *getDataLayout() {
- if (DL)
- return DL;
- DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
- DL = DLP ? &DLP->getDataLayout() : 0;
- return DL;
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ AU.addRequired<TargetTransformInfoWrapperPass>();
}
DominatorTree *getDominatorTree() {
}
TargetLibraryInfo *getTargetLibraryInfo() {
- return TLI ? TLI : (TLI = &getAnalysis<TargetLibraryInfo>());
+ if (!TLI)
+ TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+
+ return TLI;
}
const TargetTransformInfo *getTargetTransformInfo() {
- return TTI ? TTI : (TTI = &getAnalysis<TargetTransformInfo>());
+ return TTI ? TTI
+ : (TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(
+ *CurLoop->getHeader()->getParent()));
}
Loop *getLoop() const { return CurLoop; }
bool runOnNoncountableLoop();
bool runOnCountableLoop();
};
-}
+} // namespace
char LoopIdiomRecognize::ID = 0;
INITIALIZE_PASS_BEGIN(LoopIdiomRecognize, "loop-idiom", "Recognize loop idioms",
false, false)
-INITIALIZE_PASS_DEPENDENCY(LoopInfo)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
INITIALIZE_PASS_DEPENDENCY(LCSSA)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
-INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_END(LoopIdiomRecognize, "loop-idiom", "Recognize loop idioms",
false, false)
/// 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, ScalarEvolution &SE,
+static void deleteDeadInstruction(Instruction *I,
const TargetLibraryInfo *TLI) {
- SmallVector<Instruction*, 32> NowDeadInsts;
-
- NowDeadInsts.push_back(I);
-
- // Before we touch this instruction, remove it from SE!
- do {
- Instruction *DeadInst = NowDeadInsts.pop_back_val();
-
- // This instruction is dead, zap it, in stages. Start by removing it from
- // SCEV.
- SE.forgetValue(DeadInst);
-
- for (unsigned op = 0, e = DeadInst->getNumOperands(); op != e; ++op) {
- Value *Op = DeadInst->getOperand(op);
- DeadInst->setOperand(op, 0);
-
- // If this operand just became dead, add it to the NowDeadInsts list.
- if (!Op->use_empty()) continue;
-
- if (Instruction *OpI = dyn_cast<Instruction>(Op))
- if (isInstructionTriviallyDead(OpI, TLI))
- NowDeadInsts.push_back(OpI);
- }
-
- DeadInst->eraseFromParent();
-
- } while (!NowDeadInsts.empty());
-}
-
-/// deleteIfDeadInstruction - If the specified value is a dead instruction,
-/// delete it and any recursively used instructions.
-static void deleteIfDeadInstruction(Value *V, ScalarEvolution &SE,
- const TargetLibraryInfo *TLI) {
- if (Instruction *I = dyn_cast<Instruction>(V))
- if (isInstructionTriviallyDead(I, TLI))
- deleteDeadInstruction(I, SE, 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);
}
//===----------------------------------------------------------------------===//
// the concern of breaking data dependence.
bool LIRUtil::isAlmostEmpty(BasicBlock *BB) {
if (BranchInst *Br = getBranch(BB)) {
- return Br->isUnconditional() && BB->size() == 1;
+ return Br->isUnconditional() && Br == BB->begin();
}
return false;
}
-Value *LIRUtil::getBrCondtion(BasicBlock *BB) {
- BranchInst *Br = getBranch(BB);
- return Br ? Br->getCondition() : 0;
-}
-
BasicBlock *LIRUtil::getPrecondBb(BasicBlock *PreHead) {
if (BasicBlock *BB = PreHead->getSinglePredecessor()) {
BranchInst *Br = getBranch(BB);
- return Br && Br->isConditional() ? BB : 0;
+ return Br && Br->isConditional() ? BB : nullptr;
}
- return 0;
+ return nullptr;
}
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
NclPopcountRecognize::NclPopcountRecognize(LoopIdiomRecognize &TheLIR):
- LIR(TheLIR), CurLoop(TheLIR.getLoop()), PreCondBB(0) {
+ LIR(TheLIR), CurLoop(TheLIR.getLoop()), PreCondBB(nullptr) {
}
bool NclPopcountRecognize::preliminaryScreen() {
return true;
}
-Value *NclPopcountRecognize::matchCondition (BranchInst *Br,
- BasicBlock *LoopEntry) const {
+Value *NclPopcountRecognize::matchCondition(BranchInst *Br,
+ BasicBlock *LoopEntry) const {
if (!Br || !Br->isConditional())
- return 0;
+ return nullptr;
ICmpInst *Cond = dyn_cast<ICmpInst>(Br->getCondition());
if (!Cond)
- return 0;
+ return nullptr;
ConstantInt *CmpZero = dyn_cast<ConstantInt>(Cond->getOperand(1));
if (!CmpZero || !CmpZero->isZero())
- return 0;
+ return nullptr;
ICmpInst::Predicate Pred = Cond->getPredicate();
if ((Pred == ICmpInst::ICMP_NE && Br->getSuccessor(0) == LoopEntry) ||
(Pred == ICmpInst::ICMP_EQ && Br->getSuccessor(1) == LoopEntry))
return Cond->getOperand(0);
- return 0;
+ return nullptr;
}
bool NclPopcountRecognize::detectIdiom(Instruction *&CntInst,
Value *VarX1, *VarX0;
PHINode *PhiX, *CountPhi;
- DefX2 = CountInst = 0;
- VarX1 = VarX0 = 0;
- PhiX = CountPhi = 0;
+ DefX2 = CountInst = nullptr;
+ VarX1 = VarX0 = nullptr;
+ PhiX = CountPhi = nullptr;
LoopEntry = *(CurLoop->block_begin());
// step 1: Check if the loop-back branch is in desirable form.
// step 4: Find the instruction which count the population: cnt2 = cnt1 + 1
{
- CountInst = NULL;
+ CountInst = nullptr;
for (BasicBlock::iterator Iter = LoopEntry->getFirstNonPHI(),
IterE = LoopEntry->end(); Iter != IterE; Iter++) {
Instruction *Inst = Iter;
cast<ICmpInst>(Builder.CreateICmp(PreCond->getPredicate(), Opnd0, Opnd1));
PreCond->replaceAllUsesWith(NewPreCond);
- deleteDeadInstruction(PreCond, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(PreCond, TLI);
}
// Step 3: Note that the population count is exactly the trip count of the
// Step 4: All the references to the original population counter outside
// the loop are replaced with the NewCount -- the value returned from
// __builtin_ctpop().
- {
- SmallVector<Value *, 4> CntUses;
- for (User *U : CntInst->users())
- if (cast<Instruction>(U)->getParent() != Body)
- CntUses.push_back(U);
- for (unsigned Idx = 0; Idx < CntUses.size(); Idx++) {
- (cast<Instruction>(CntUses[Idx]))->replaceUsesOfWith(CntInst, NewCount);
- }
- }
+ CntInst->replaceUsesOutsideBlock(NewCount, Body);
// step 5: Forget the "non-computable" trip-count SCEV associated with the
// loop. The loop would otherwise not be deleted even if it becomes empty.
bool LoopIdiomRecognize::runOnCountableLoop() {
const SCEV *BECount = SE->getBackedgeTakenCount(CurLoop);
- if (isa<SCEVCouldNotCompute>(BECount)) return false;
+ assert(!isa<SCEVCouldNotCompute>(BECount) &&
+ "runOnCountableLoop() called on a loop without a predictable"
+ "backedge-taken count");
// If this loop executes exactly one time, then it should be peeled, not
// optimized by this pass.
if (BECst->getValue()->getValue() == 0)
return false;
- // We require target data for now.
- if (!getDataLayout())
- return false;
-
// set DT
(void)getDominatorTree();
- LoopInfo &LI = getAnalysis<LoopInfo>();
- TLI = &getAnalysis<TargetLibraryInfo>();
+ LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+ TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
// set TLI
(void)getTargetLibraryInfo();
bool MadeChange = false;
// Scan all the blocks in the loop that are not in subloops.
- for (Loop::block_iterator BI = CurLoop->block_begin(),
- E = CurLoop->block_end(); BI != E; ++BI) {
+ for (auto *BB : CurLoop->getBlocks()) {
// Ignore blocks in subloops.
- if (LI.getLoopFor(*BI) != CurLoop)
+ if (LI.getLoopFor(BB) != CurLoop)
continue;
- MadeChange |= runOnLoopBlock(*BI, BECount, ExitBlocks);
+ MadeChange |= runOnLoopBlock(BB, BECount, ExitBlocks);
}
return MadeChange;
}
// If processing the store invalidated our iterator, start over from the
// top of the block.
- if (InstPtr == 0)
+ if (!InstPtr)
I = BB->begin();
continue;
}
// If processing the memset invalidated our iterator, start over from the
// top of the block.
- if (InstPtr == 0)
+ if (!InstPtr)
I = BB->begin();
continue;
}
Value *StorePtr = SI->getPointerOperand();
// Reject stores that are so large that they overflow an unsigned.
- uint64_t SizeInBits = DL->getTypeSizeInBits(StoredVal->getType());
+ auto &DL = CurLoop->getHeader()->getModule()->getDataLayout();
+ uint64_t SizeInBits = DL.getTypeSizeInBits(StoredVal->getType());
if ((SizeInBits & 7) || (SizeInBits >> 32) != 0)
return false;
// random store we can't handle.
const SCEVAddRecExpr *StoreEv =
dyn_cast<SCEVAddRecExpr>(SE->getSCEV(StorePtr));
- if (StoreEv == 0 || StoreEv->getLoop() != CurLoop || !StoreEv->isAffine())
+ if (!StoreEv || StoreEv->getLoop() != CurLoop || !StoreEv->isAffine())
return false;
// Check to see if the stride matches the size of the store. If so, then we
unsigned StoreSize = (unsigned)SizeInBits >> 3;
const SCEVConstant *Stride = dyn_cast<SCEVConstant>(StoreEv->getOperand(1));
- if (Stride == 0 || StoreSize != Stride->getValue()->getValue()) {
+ if (!Stride || StoreSize != Stride->getValue()->getValue()) {
// TODO: Could also handle negative stride here someday, that will require
// the validity check in mayLoopAccessLocation to be updated though.
// Enable this to print exact negative strides.
// loop, which indicates a strided store. If we have something else, it's a
// random store we can't handle.
const SCEVAddRecExpr *Ev = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(Pointer));
- if (Ev == 0 || Ev->getLoop() != CurLoop || !Ev->isAffine())
+ if (!Ev || Ev->getLoop() != CurLoop || !Ev->isAffine())
return false;
// Reject memsets that are so large that they overflow an unsigned.
// TODO: Could also handle negative stride here someday, that will require the
// validity check in mayLoopAccessLocation to be updated though.
- if (Stride == 0 || MSI->getLength() != Stride->getValue())
+ if (!Stride || MSI->getLength() != Stride->getValue())
return false;
return processLoopStridedStore(Pointer, (unsigned)SizeInBytes,
// 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.
- uint64_t AccessSize = AliasAnalysis::UnknownSize;
+ uint64_t AccessSize = MemoryLocation::UnknownSize;
// If the loop iterates a fixed number of times, we can refine the access size
// to be exactly the size of the memset, which is (BECount+1)*StoreSize
// operand in the store. Store to &A[i] of 100 will always return may alias
// with store of &A[100], we need to StoreLoc to be "A" with size of 100,
// which will then no-alias a store to &A[100].
- AliasAnalysis::Location StoreLoc(Ptr, AccessSize);
+ MemoryLocation StoreLoc(Ptr, AccessSize);
for (Loop::block_iterator BI = L->block_begin(), E = L->block_end(); BI != E;
++BI)
// array. We could theoretically do a store to an alloca or something, but
// that doesn't seem worthwhile.
Constant *C = dyn_cast<Constant>(V);
- if (C == 0) return 0;
+ if (!C) return nullptr;
// Only handle simple values that are a power of two bytes in size.
uint64_t Size = DL.getTypeSizeInBits(V->getType());
if (Size == 0 || (Size & 7) || (Size & (Size-1)))
- return 0;
+ return nullptr;
// Don't care enough about darwin/ppc to implement this.
if (DL.isBigEndian())
- return 0;
+ return nullptr;
// Convert to size in bytes.
Size /= 8;
// TODO: If CI is larger than 16-bytes, we can try slicing it in half to see
// if the top and bottom are the same (e.g. for vectors and large integers).
- if (Size > 16) return 0;
+ if (Size > 16) return nullptr;
// If the constant is exactly 16 bytes, just use it.
if (Size == 16) return C;
// are stored. A store of i32 0x01020304 can never be turned into a memset,
// but it can be turned into memset_pattern if the target supports it.
Value *SplatValue = isBytewiseValue(StoredVal);
- Constant *PatternValue = 0;
-
+ Constant *PatternValue = nullptr;
+ auto &DL = CurLoop->getHeader()->getModule()->getDataLayout();
unsigned DestAS = DestPtr->getType()->getPointerAddressSpace();
// If we're allowed to form a memset, and the stored value would be acceptable
// promote the memset.
CurLoop->isLoopInvariant(SplatValue)) {
// Keep and use SplatValue.
- PatternValue = 0;
- } else if (DestAS == 0 &&
- TLI->has(LibFunc::memset_pattern16) &&
- (PatternValue = getMemSetPatternValue(StoredVal, *DL))) {
+ PatternValue = nullptr;
+ } else if (DestAS == 0 && TLI->has(LibFunc::memset_pattern16) &&
+ (PatternValue = getMemSetPatternValue(StoredVal, DL))) {
// Don't create memset_pattern16s with address spaces.
// It looks like we can use PatternValue!
- SplatValue = 0;
+ SplatValue = nullptr;
} else {
// Otherwise, this isn't an idiom we can transform. For example, we can't
// do anything with a 3-byte store.
// header. This allows us to insert code for it in the preheader.
BasicBlock *Preheader = CurLoop->getLoopPreheader();
IRBuilder<> Builder(Preheader->getTerminator());
- SCEVExpander Expander(*SE, "loop-idiom");
+ SCEVExpander Expander(*SE, DL, "loop-idiom");
Type *DestInt8PtrTy = Builder.getInt8PtrTy(DestAS);
StoreSize, getAnalysis<AliasAnalysis>(), TheStore)) {
Expander.clear();
// If we generated new code for the base pointer, clean up.
- deleteIfDeadInstruction(BasePtr, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(BasePtr, TLI);
return false;
}
Int8PtrTy,
Int8PtrTy,
IntPtr,
- (void*)0);
+ (void*)nullptr);
// 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::InternalLinkage,
+ GlobalValue::PrivateLinkage,
PatternValue, ".memset_pattern");
GV->setUnnamedAddr(true); // Ok to merge these.
GV->setAlignment(16);
Value *PatternPtr = ConstantExpr::getBitCast(GV, Int8PtrTy);
- NewCall = Builder.CreateCall3(MSP, BasePtr, PatternPtr, NumBytes);
+ NewCall = Builder.CreateCall(MSP, {BasePtr, PatternPtr, NumBytes});
}
DEBUG(dbgs() << " Formed memset: " << *NewCall << "\n"
// Okay, the memset has been formed. Zap the original store and anything that
// feeds into it.
- deleteDeadInstruction(TheStore, *SE, TLI);
+ deleteDeadInstruction(TheStore, TLI);
++NumMemSet;
return true;
}
// header. This allows us to insert code for it in the preheader.
BasicBlock *Preheader = CurLoop->getLoopPreheader();
IRBuilder<> Builder(Preheader->getTerminator());
- SCEVExpander Expander(*SE, "loop-idiom");
+ const DataLayout &DL = Preheader->getModule()->getDataLayout();
+ SCEVExpander Expander(*SE, DL, "loop-idiom");
// Okay, we have a strided store "p[i]" of a loaded value. We can turn
// this into a memcpy in the loop preheader now if we want. However, this
getAnalysis<AliasAnalysis>(), SI)) {
Expander.clear();
// If we generated new code for the base pointer, clean up.
- deleteIfDeadInstruction(StoreBasePtr, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(StoreBasePtr, TLI);
return false;
}
StoreSize, getAnalysis<AliasAnalysis>(), SI)) {
Expander.clear();
// If we generated new code for the base pointer, clean up.
- deleteIfDeadInstruction(LoadBasePtr, *SE, TLI);
- deleteIfDeadInstruction(StoreBasePtr, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(LoadBasePtr, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(StoreBasePtr, TLI);
return false;
}
// Okay, the memset has been formed. Zap the original store and anything that
// feeds into it.
- deleteDeadInstruction(SI, *SE, TLI);
+ deleteDeadInstruction(SI, TLI);
++NumMemCpy;
return true;
}