#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PatternMatch.h"
+#include "llvm/IR/Statepoint.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/IR/ValueMap.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/Transforms/Utils/BypassSlowDivision.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
using namespace llvm;
using namespace llvm::PatternMatch;
"disable-cgp-branch-opts", cl::Hidden, cl::init(false),
cl::desc("Disable branch optimizations in CodeGenPrepare"));
+static cl::opt<bool>
+ DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false),
+ cl::desc("Disable GC optimizations in CodeGenPrepare"));
+
static cl::opt<bool> DisableSelectToBranch(
"disable-cgp-select2branch", cl::Hidden, cl::init(false),
cl::desc("Disable select to branch conversion."));
"stress-cgp-store-extract", cl::Hidden, cl::init(false),
cl::desc("Stress test store(extract) optimizations in CodeGenPrepare"));
+static cl::opt<bool> DisableExtLdPromotion(
+ "disable-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
+ cl::desc("Disable ext(promotable(ld)) -> promoted(ext(ld)) optimization in "
+ "CodeGenPrepare"));
+
+static cl::opt<bool> StressExtLdPromotion(
+ "stress-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
+ cl::desc("Stress test ext(promotable(ld)) -> promoted(ext(ld)) "
+ "optimization in CodeGenPrepare"));
+
namespace {
typedef SmallPtrSet<Instruction *, 16> SetOfInstrs;
struct TypeIsSExt {
TypeIsSExt(Type *Ty, bool IsSExt) : Ty(Ty), IsSExt(IsSExt) {}
};
typedef DenseMap<Instruction *, TypeIsSExt> InstrToOrigTy;
+class TypePromotionTransaction;
class CodeGenPrepare : public FunctionPass {
/// TLI - Keep a pointer of a TargetLowering to consult for determining
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addPreserved<DominatorTreeWrapperPass>();
- AU.addRequired<TargetLibraryInfo>();
- AU.addRequired<TargetTransformInfo>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ AU.addRequired<TargetTransformInfoWrapperPass>();
}
private:
bool EliminateMostlyEmptyBlocks(Function &F);
bool CanMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
void EliminateMostlyEmptyBlock(BasicBlock *BB);
- bool OptimizeBlock(BasicBlock &BB);
- bool OptimizeInst(Instruction *I);
+ bool OptimizeBlock(BasicBlock &BB, bool& ModifiedDT);
+ bool OptimizeInst(Instruction *I, bool& ModifiedDT);
bool OptimizeMemoryInst(Instruction *I, Value *Addr, Type *AccessTy);
bool OptimizeInlineAsmInst(CallInst *CS);
- bool OptimizeCallInst(CallInst *CI);
- bool MoveExtToFormExtLoad(Instruction *I);
+ bool OptimizeCallInst(CallInst *CI, bool& ModifiedDT);
+ bool MoveExtToFormExtLoad(Instruction *&I);
bool OptimizeExtUses(Instruction *I);
bool OptimizeSelectInst(SelectInst *SI);
bool OptimizeShuffleVectorInst(ShuffleVectorInst *SI);
bool DupRetToEnableTailCallOpts(BasicBlock *BB);
bool PlaceDbgValues(Function &F);
bool sinkAndCmp(Function &F);
+ bool ExtLdPromotion(TypePromotionTransaction &TPT, LoadInst *&LI,
+ Instruction *&Inst,
+ const SmallVectorImpl<Instruction *> &Exts,
+ unsigned CreatedInst);
bool splitBranchCondition(Function &F);
+ bool simplifyOffsetableRelocate(Instruction &I);
};
}
ModifiedDT = false;
if (TM)
- TLI = TM->getSubtargetImpl()->getTargetLowering();
- TLInfo = &getAnalysis<TargetLibraryInfo>();
- TTI = &getAnalysis<TargetTransformInfo>();
+ TLI = TM->getSubtargetImpl(F)->getTargetLowering();
+ TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+ TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
DominatorTreeWrapperPass *DTWP =
getAnalysisIfAvailable<DominatorTreeWrapperPass>();
DT = DTWP ? &DTWP->getDomTree() : nullptr;
MadeChange = false;
for (Function::iterator I = F.begin(); I != F.end(); ) {
BasicBlock *BB = I++;
- MadeChange |= OptimizeBlock(*BB);
+ bool ModifiedDTOnIteration = false;
+ MadeChange |= OptimizeBlock(*BB, ModifiedDTOnIteration);
+
+ // Restart BB iteration if the dominator tree of the Function was changed
+ ModifiedDT |= ModifiedDTOnIteration;
+ if (ModifiedDTOnIteration)
+ break;
}
EverMadeChange |= MadeChange;
}
if (!DisableBranchOpts) {
MadeChange = false;
SmallPtrSet<BasicBlock*, 8> WorkList;
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
- SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
- MadeChange |= ConstantFoldTerminator(BB, true);
+ for (BasicBlock &BB : F) {
+ SmallVector<BasicBlock *, 2> Successors(succ_begin(&BB), succ_end(&BB));
+ MadeChange |= ConstantFoldTerminator(&BB, true);
if (!MadeChange) continue;
for (SmallVectorImpl<BasicBlock*>::iterator
EverMadeChange |= MadeChange;
}
+ if (!DisableGCOpts) {
+ SmallVector<Instruction *, 2> Statepoints;
+ for (BasicBlock &BB : F)
+ for (Instruction &I : BB)
+ if (isStatepoint(I))
+ Statepoints.push_back(&I);
+ for (auto &I : Statepoints)
+ EverMadeChange |= simplifyOffsetableRelocate(*I);
+ }
+
if (ModifiedDT && DT)
DT->recalculate(F);
// Remember if SinglePred was the entry block of the function.
// If so, we will need to move BB back to the entry position.
bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
- MergeBasicBlockIntoOnlyPred(BB, this);
+ MergeBasicBlockIntoOnlyPred(BB, DT);
if (isEntry && BB != &BB->getParent()->getEntryBlock())
BB->moveBefore(&BB->getParent()->getEntryBlock());
// Remember if SinglePred was the entry block of the function. If so, we
// will need to move BB back to the entry position.
bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
- MergeBasicBlockIntoOnlyPred(DestBB, this);
+ MergeBasicBlockIntoOnlyPred(DestBB, DT);
if (isEntry && BB != &BB->getParent()->getEntryBlock())
BB->moveBefore(&BB->getParent()->getEntryBlock());
DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
}
+// Computes a map of base pointer relocation instructions to corresponding
+// derived pointer relocation instructions given a vector of all relocate calls
+static void computeBaseDerivedRelocateMap(
+ const SmallVectorImpl<User *> &AllRelocateCalls,
+ DenseMap<IntrinsicInst *, SmallVector<IntrinsicInst *, 2>> &
+ RelocateInstMap) {
+ // Collect information in two maps: one primarily for locating the base object
+ // while filling the second map; the second map is the final structure holding
+ // a mapping between Base and corresponding Derived relocate calls
+ DenseMap<std::pair<unsigned, unsigned>, IntrinsicInst *> RelocateIdxMap;
+ for (auto &U : AllRelocateCalls) {
+ GCRelocateOperands ThisRelocate(U);
+ IntrinsicInst *I = cast<IntrinsicInst>(U);
+ auto K = std::make_pair(ThisRelocate.basePtrIndex(),
+ ThisRelocate.derivedPtrIndex());
+ RelocateIdxMap.insert(std::make_pair(K, I));
+ }
+ for (auto &Item : RelocateIdxMap) {
+ std::pair<unsigned, unsigned> Key = Item.first;
+ if (Key.first == Key.second)
+ // Base relocation: nothing to insert
+ continue;
+
+ IntrinsicInst *I = Item.second;
+ auto BaseKey = std::make_pair(Key.first, Key.first);
+ IntrinsicInst *Base = RelocateIdxMap[BaseKey];
+ if (!Base)
+ // TODO: We might want to insert a new base object relocate and gep off
+ // that, if there are enough derived object relocates.
+ continue;
+ RelocateInstMap[Base].push_back(I);
+ }
+}
+
+// Accepts a GEP and extracts the operands into a vector provided they're all
+// small integer constants
+static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
+ SmallVectorImpl<Value *> &OffsetV) {
+ for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
+ // Only accept small constant integer operands
+ auto Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
+ if (!Op || Op->getZExtValue() > 20)
+ return false;
+ }
+
+ for (unsigned i = 1; i < GEP->getNumOperands(); i++)
+ OffsetV.push_back(GEP->getOperand(i));
+ return true;
+}
+
+// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
+// replace, computes a replacement, and affects it.
+static bool
+simplifyRelocatesOffABase(IntrinsicInst *RelocatedBase,
+ const SmallVectorImpl<IntrinsicInst *> &Targets) {
+ bool MadeChange = false;
+ for (auto &ToReplace : Targets) {
+ GCRelocateOperands MasterRelocate(RelocatedBase);
+ GCRelocateOperands ThisRelocate(ToReplace);
+
+ assert(ThisRelocate.basePtrIndex() == MasterRelocate.basePtrIndex() &&
+ "Not relocating a derived object of the original base object");
+ if (ThisRelocate.basePtrIndex() == ThisRelocate.derivedPtrIndex()) {
+ // A duplicate relocate call. TODO: coalesce duplicates.
+ continue;
+ }
+
+ Value *Base = ThisRelocate.basePtr();
+ auto Derived = dyn_cast<GetElementPtrInst>(ThisRelocate.derivedPtr());
+ if (!Derived || Derived->getPointerOperand() != Base)
+ continue;
+
+ SmallVector<Value *, 2> OffsetV;
+ if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
+ continue;
+
+ // Create a Builder and replace the target callsite with a gep
+ IRBuilder<> Builder(ToReplace);
+ Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
+ Value *Replacement =
+ Builder.CreateGEP(RelocatedBase, makeArrayRef(OffsetV));
+ Instruction *ReplacementInst = cast<Instruction>(Replacement);
+ ReplacementInst->removeFromParent();
+ ReplacementInst->insertAfter(RelocatedBase);
+ Replacement->takeName(ToReplace);
+ ToReplace->replaceAllUsesWith(Replacement);
+ ToReplace->eraseFromParent();
+
+ MadeChange = true;
+ }
+ return MadeChange;
+}
+
+// Turns this:
+//
+// %base = ...
+// %ptr = gep %base + 15
+// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
+// %base' = relocate(%tok, i32 4, i32 4)
+// %ptr' = relocate(%tok, i32 4, i32 5)
+// %val = load %ptr'
+//
+// into this:
+//
+// %base = ...
+// %ptr = gep %base + 15
+// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
+// %base' = gc.relocate(%tok, i32 4, i32 4)
+// %ptr' = gep %base' + 15
+// %val = load %ptr'
+bool CodeGenPrepare::simplifyOffsetableRelocate(Instruction &I) {
+ bool MadeChange = false;
+ SmallVector<User *, 2> AllRelocateCalls;
+
+ for (auto *U : I.users())
+ if (isGCRelocate(dyn_cast<Instruction>(U)))
+ // Collect all the relocate calls associated with a statepoint
+ AllRelocateCalls.push_back(U);
+
+ // We need atleast one base pointer relocation + one derived pointer
+ // relocation to mangle
+ if (AllRelocateCalls.size() < 2)
+ return false;
+
+ // RelocateInstMap is a mapping from the base relocate instruction to the
+ // corresponding derived relocate instructions
+ DenseMap<IntrinsicInst *, SmallVector<IntrinsicInst *, 2>> RelocateInstMap;
+ computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
+ if (RelocateInstMap.empty())
+ return false;
+
+ for (auto &Item : RelocateInstMap)
+ // Item.first is the RelocatedBase to offset against
+ // Item.second is the vector of Targets to replace
+ MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
+ return MadeChange;
+}
+
/// SinkCast - Sink the specified cast instruction into its user blocks
static bool SinkCast(CastInst *CI) {
BasicBlock *DefBB = CI->getParent();
return MadeChange;
}
-namespace {
-class CodeGenPrepareFortifiedLibCalls : public SimplifyFortifiedLibCalls {
-protected:
- void replaceCall(Value *With) override {
- CI->replaceAllUsesWith(With);
- CI->eraseFromParent();
+// ScalarizeMaskedLoad() translates masked load intrinsic, like
+// <16 x i32 > @llvm.masked.load( <16 x i32>* %addr, i32 align,
+// <16 x i1> %mask, <16 x i32> %passthru)
+// to a chain of basic blocks, whith loading element one-by-one if
+// the appropriate mask bit is set
+//
+// %1 = bitcast i8* %addr to i32*
+// %2 = extractelement <16 x i1> %mask, i32 0
+// %3 = icmp eq i1 %2, true
+// br i1 %3, label %cond.load, label %else
+//
+//cond.load: ; preds = %0
+// %4 = getelementptr i32* %1, i32 0
+// %5 = load i32* %4
+// %6 = insertelement <16 x i32> undef, i32 %5, i32 0
+// br label %else
+//
+//else: ; preds = %0, %cond.load
+// %res.phi.else = phi <16 x i32> [ %6, %cond.load ], [ undef, %0 ]
+// %7 = extractelement <16 x i1> %mask, i32 1
+// %8 = icmp eq i1 %7, true
+// br i1 %8, label %cond.load1, label %else2
+//
+//cond.load1: ; preds = %else
+// %9 = getelementptr i32* %1, i32 1
+// %10 = load i32* %9
+// %11 = insertelement <16 x i32> %res.phi.else, i32 %10, i32 1
+// br label %else2
+//
+//else2: ; preds = %else, %cond.load1
+// %res.phi.else3 = phi <16 x i32> [ %11, %cond.load1 ], [ %res.phi.else, %else ]
+// %12 = extractelement <16 x i1> %mask, i32 2
+// %13 = icmp eq i1 %12, true
+// br i1 %13, label %cond.load4, label %else5
+//
+static void ScalarizeMaskedLoad(CallInst *CI) {
+ Value *Ptr = CI->getArgOperand(0);
+ Value *Src0 = CI->getArgOperand(3);
+ Value *Mask = CI->getArgOperand(2);
+ VectorType *VecType = dyn_cast<VectorType>(CI->getType());
+ Type *EltTy = VecType->getElementType();
+
+ assert(VecType && "Unexpected return type of masked load intrinsic");
+
+ IRBuilder<> Builder(CI->getContext());
+ Instruction *InsertPt = CI;
+ BasicBlock *IfBlock = CI->getParent();
+ BasicBlock *CondBlock = nullptr;
+ BasicBlock *PrevIfBlock = CI->getParent();
+ Builder.SetInsertPoint(InsertPt);
+
+ Builder.SetCurrentDebugLocation(CI->getDebugLoc());
+
+ // Bitcast %addr fron i8* to EltTy*
+ Type *NewPtrType =
+ EltTy->getPointerTo(cast<PointerType>(Ptr->getType())->getAddressSpace());
+ Value *FirstEltPtr = Builder.CreateBitCast(Ptr, NewPtrType);
+ Value *UndefVal = UndefValue::get(VecType);
+
+ // The result vector
+ Value *VResult = UndefVal;
+
+ PHINode *Phi = nullptr;
+ Value *PrevPhi = UndefVal;
+
+ unsigned VectorWidth = VecType->getNumElements();
+ for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
+
+ // Fill the "else" block, created in the previous iteration
+ //
+ // %res.phi.else3 = phi <16 x i32> [ %11, %cond.load1 ], [ %res.phi.else, %else ]
+ // %mask_1 = extractelement <16 x i1> %mask, i32 Idx
+ // %to_load = icmp eq i1 %mask_1, true
+ // br i1 %to_load, label %cond.load, label %else
+ //
+ if (Idx > 0) {
+ Phi = Builder.CreatePHI(VecType, 2, "res.phi.else");
+ Phi->addIncoming(VResult, CondBlock);
+ Phi->addIncoming(PrevPhi, PrevIfBlock);
+ PrevPhi = Phi;
+ VResult = Phi;
+ }
+
+ Value *Predicate = Builder.CreateExtractElement(Mask, Builder.getInt32(Idx));
+ Value *Cmp = Builder.CreateICmp(ICmpInst::ICMP_EQ, Predicate,
+ ConstantInt::get(Predicate->getType(), 1));
+
+ // Create "cond" block
+ //
+ // %EltAddr = getelementptr i32* %1, i32 0
+ // %Elt = load i32* %EltAddr
+ // VResult = insertelement <16 x i32> VResult, i32 %Elt, i32 Idx
+ //
+ CondBlock = IfBlock->splitBasicBlock(InsertPt, "cond.load");
+ Builder.SetInsertPoint(InsertPt);
+
+ Value* Gep = Builder.CreateInBoundsGEP(FirstEltPtr, Builder.getInt32(Idx));
+ LoadInst* Load = Builder.CreateLoad(Gep, false);
+ VResult = Builder.CreateInsertElement(VResult, Load, Builder.getInt32(Idx));
+
+ // Create "else" block, fill it in the next iteration
+ BasicBlock *NewIfBlock = CondBlock->splitBasicBlock(InsertPt, "else");
+ Builder.SetInsertPoint(InsertPt);
+ Instruction *OldBr = IfBlock->getTerminator();
+ BranchInst::Create(CondBlock, NewIfBlock, Cmp, OldBr);
+ OldBr->eraseFromParent();
+ PrevIfBlock = IfBlock;
+ IfBlock = NewIfBlock;
}
- bool isFoldable(unsigned SizeCIOp, unsigned, bool) const override {
- if (ConstantInt *SizeCI =
- dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp)))
- return SizeCI->isAllOnesValue();
- return false;
+
+ Phi = Builder.CreatePHI(VecType, 2, "res.phi.select");
+ Phi->addIncoming(VResult, CondBlock);
+ Phi->addIncoming(PrevPhi, PrevIfBlock);
+ Value *NewI = Builder.CreateSelect(Mask, Phi, Src0);
+ CI->replaceAllUsesWith(NewI);
+ CI->eraseFromParent();
+}
+
+// ScalarizeMaskedStore() translates masked store intrinsic, like
+// void @llvm.masked.store(<16 x i32> %src, <16 x i32>* %addr, i32 align,
+// <16 x i1> %mask)
+// to a chain of basic blocks, that stores element one-by-one if
+// the appropriate mask bit is set
+//
+// %1 = bitcast i8* %addr to i32*
+// %2 = extractelement <16 x i1> %mask, i32 0
+// %3 = icmp eq i1 %2, true
+// br i1 %3, label %cond.store, label %else
+//
+// cond.store: ; preds = %0
+// %4 = extractelement <16 x i32> %val, i32 0
+// %5 = getelementptr i32* %1, i32 0
+// store i32 %4, i32* %5
+// br label %else
+//
+// else: ; preds = %0, %cond.store
+// %6 = extractelement <16 x i1> %mask, i32 1
+// %7 = icmp eq i1 %6, true
+// br i1 %7, label %cond.store1, label %else2
+//
+// cond.store1: ; preds = %else
+// %8 = extractelement <16 x i32> %val, i32 1
+// %9 = getelementptr i32* %1, i32 1
+// store i32 %8, i32* %9
+// br label %else2
+// . . .
+static void ScalarizeMaskedStore(CallInst *CI) {
+ Value *Ptr = CI->getArgOperand(1);
+ Value *Src = CI->getArgOperand(0);
+ Value *Mask = CI->getArgOperand(3);
+
+ VectorType *VecType = dyn_cast<VectorType>(Src->getType());
+ Type *EltTy = VecType->getElementType();
+
+ assert(VecType && "Unexpected data type in masked store intrinsic");
+
+ IRBuilder<> Builder(CI->getContext());
+ Instruction *InsertPt = CI;
+ BasicBlock *IfBlock = CI->getParent();
+ Builder.SetInsertPoint(InsertPt);
+ Builder.SetCurrentDebugLocation(CI->getDebugLoc());
+
+ // Bitcast %addr fron i8* to EltTy*
+ Type *NewPtrType =
+ EltTy->getPointerTo(cast<PointerType>(Ptr->getType())->getAddressSpace());
+ Value *FirstEltPtr = Builder.CreateBitCast(Ptr, NewPtrType);
+
+ unsigned VectorWidth = VecType->getNumElements();
+ for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
+
+ // Fill the "else" block, created in the previous iteration
+ //
+ // %mask_1 = extractelement <16 x i1> %mask, i32 Idx
+ // %to_store = icmp eq i1 %mask_1, true
+ // br i1 %to_load, label %cond.store, label %else
+ //
+ Value *Predicate = Builder.CreateExtractElement(Mask, Builder.getInt32(Idx));
+ Value *Cmp = Builder.CreateICmp(ICmpInst::ICMP_EQ, Predicate,
+ ConstantInt::get(Predicate->getType(), 1));
+
+ // Create "cond" block
+ //
+ // %OneElt = extractelement <16 x i32> %Src, i32 Idx
+ // %EltAddr = getelementptr i32* %1, i32 0
+ // %store i32 %OneElt, i32* %EltAddr
+ //
+ BasicBlock *CondBlock = IfBlock->splitBasicBlock(InsertPt, "cond.store");
+ Builder.SetInsertPoint(InsertPt);
+
+ Value *OneElt = Builder.CreateExtractElement(Src, Builder.getInt32(Idx));
+ Value* Gep = Builder.CreateInBoundsGEP(FirstEltPtr, Builder.getInt32(Idx));
+ Builder.CreateStore(OneElt, Gep);
+
+ // Create "else" block, fill it in the next iteration
+ BasicBlock *NewIfBlock = CondBlock->splitBasicBlock(InsertPt, "else");
+ Builder.SetInsertPoint(InsertPt);
+ Instruction *OldBr = IfBlock->getTerminator();
+ BranchInst::Create(CondBlock, NewIfBlock, Cmp, OldBr);
+ OldBr->eraseFromParent();
+ IfBlock = NewIfBlock;
}
-};
-} // end anonymous namespace
+ CI->eraseFromParent();
+}
-bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
+bool CodeGenPrepare::OptimizeCallInst(CallInst *CI, bool& ModifiedDT) {
BasicBlock *BB = CI->getParent();
// Lower inline assembly if we can.
return true;
}
- // Lower all uses of llvm.objectsize.*
IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
- if (II && II->getIntrinsicID() == Intrinsic::objectsize) {
- bool Min = (cast<ConstantInt>(II->getArgOperand(1))->getZExtValue() == 1);
- Type *ReturnTy = CI->getType();
- Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL);
-
- // Substituting this can cause recursive simplifications, which can
- // invalidate our iterator. Use a WeakVH to hold onto it in case this
- // happens.
- WeakVH IterHandle(CurInstIterator);
+ if (II) {
+ switch (II->getIntrinsicID()) {
+ default: break;
+ case Intrinsic::objectsize: {
+ // Lower all uses of llvm.objectsize.*
+ bool Min = (cast<ConstantInt>(II->getArgOperand(1))->getZExtValue() == 1);
+ Type *ReturnTy = CI->getType();
+ Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL);
+
+ // Substituting this can cause recursive simplifications, which can
+ // invalidate our iterator. Use a WeakVH to hold onto it in case this
+ // happens.
+ WeakVH IterHandle(CurInstIterator);
+
+ replaceAndRecursivelySimplify(CI, RetVal,
+ TLI ? TLI->getDataLayout() : nullptr,
+ TLInfo, ModifiedDT ? nullptr : DT);
- replaceAndRecursivelySimplify(CI, RetVal,
- TLI ? TLI->getDataLayout() : nullptr,
- TLInfo, ModifiedDT ? nullptr : DT);
-
- // If the iterator instruction was recursively deleted, start over at the
- // start of the block.
- if (IterHandle != CurInstIterator) {
- CurInstIterator = BB->begin();
- SunkAddrs.clear();
+ // If the iterator instruction was recursively deleted, start over at the
+ // start of the block.
+ if (IterHandle != CurInstIterator) {
+ CurInstIterator = BB->begin();
+ SunkAddrs.clear();
+ }
+ return true;
+ }
+ case Intrinsic::masked_load: {
+ // Scalarize unsupported vector masked load
+ if (!TTI->isLegalMaskedLoad(CI->getType(), 1)) {
+ ScalarizeMaskedLoad(CI);
+ ModifiedDT = true;
+ return true;
+ }
+ return false;
+ }
+ case Intrinsic::masked_store: {
+ if (!TTI->isLegalMaskedStore(CI->getArgOperand(0)->getType(), 1)) {
+ ScalarizeMaskedStore(CI);
+ ModifiedDT = true;
+ return true;
+ }
+ return false;
+ }
}
- return true;
- }
- if (II && TLI) {
- SmallVector<Value*, 2> PtrOps;
- Type *AccessTy;
- if (TLI->GetAddrModeArguments(II, PtrOps, AccessTy))
- while (!PtrOps.empty())
- if (OptimizeMemoryInst(II, PtrOps.pop_back_val(), AccessTy))
- return true;
+ if (TLI) {
+ SmallVector<Value*, 2> PtrOps;
+ Type *AccessTy;
+ if (TLI->GetAddrModeArguments(II, PtrOps, AccessTy))
+ while (!PtrOps.empty())
+ if (OptimizeMemoryInst(II, PtrOps.pop_back_val(), AccessTy))
+ return true;
+ }
}
// From here on out we're working with named functions.
// Lower all default uses of _chk calls. This is very similar
// to what InstCombineCalls does, but here we are only lowering calls
- // that have the default "don't know" as the objectsize. Anything else
- // should be left alone.
- CodeGenPrepareFortifiedLibCalls Simplifier;
- return Simplifier.fold(CI, TD, TLInfo);
+ // to fortified library functions (e.g. __memcpy_chk) that have the default
+ // "don't know" as the objectsize. Anything else should be left alone.
+ FortifiedLibCallSimplifier Simplifier(TD, TLInfo, true);
+ if (Value *V = Simplifier.optimizeCall(CI)) {
+ CI->replaceAllUsesWith(V);
+ CI->eraseFromParent();
+ return true;
+ }
+ return false;
}
/// DupRetToEnableTailCallOpts - Look for opportunities to duplicate return
}
}
+/// \brief Check whether or not \p Val is a legal instruction for \p TLI.
+/// \note \p Val is assumed to be the product of some type promotion.
+/// Therefore if \p Val has an undefined state in \p TLI, this is assumed
+/// to be legal, as the non-promoted value would have had the same state.
+static bool isPromotedInstructionLegal(const TargetLowering &TLI, Value *Val) {
+ Instruction *PromotedInst = dyn_cast<Instruction>(Val);
+ if (!PromotedInst)
+ return false;
+ int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
+ // If the ISDOpcode is undefined, it was undefined before the promotion.
+ if (!ISDOpcode)
+ return true;
+ // Otherwise, check if the promoted instruction is legal or not.
+ return TLI.isOperationLegalOrCustom(
+ ISDOpcode, TLI.getValueType(PromotedInst->getType()));
+}
+
/// \brief Hepler class to perform type promotion.
class TypePromotionHelper {
/// \brief Utility function to check whether or not a sign or zero extension
/// \p PromotedInsts maps the instructions to their type before promotion.
/// \p CreatedInsts[out] contains how many non-free instructions have been
/// created to promote the operand of Ext.
+ /// Newly added extensions are inserted in \p Exts.
+ /// Newly added truncates are inserted in \p Truncs.
/// Should never be called directly.
/// \return The promoted value which is used instead of Ext.
- static Value *promoteOperandForTruncAndAnyExt(Instruction *Ext,
- TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts);
+ static Value *promoteOperandForTruncAndAnyExt(
+ Instruction *Ext, TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
+ SmallVectorImpl<Instruction *> *Exts,
+ SmallVectorImpl<Instruction *> *Truncs);
/// \brief Utility function to promote the operand of \p Ext when this
/// operand is promotable and is not a supported trunc or sext.
/// \p PromotedInsts maps the instructions to their type before promotion.
/// \p CreatedInsts[out] contains how many non-free instructions have been
/// created to promote the operand of Ext.
+ /// Newly added extensions are inserted in \p Exts.
+ /// Newly added truncates are inserted in \p Truncs.
/// Should never be called directly.
/// \return The promoted value which is used instead of Ext.
- static Value *promoteOperandForOther(Instruction *Ext,
- TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts, bool IsSExt);
+ static Value *
+ promoteOperandForOther(Instruction *Ext, TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
+ SmallVectorImpl<Instruction *> *Exts,
+ SmallVectorImpl<Instruction *> *Truncs, bool IsSExt);
/// \see promoteOperandForOther.
- static Value *signExtendOperandForOther(Instruction *Ext,
- TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts) {
- return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInsts, true);
+ static Value *
+ signExtendOperandForOther(Instruction *Ext, TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts,
+ unsigned &CreatedInsts,
+ SmallVectorImpl<Instruction *> *Exts,
+ SmallVectorImpl<Instruction *> *Truncs) {
+ return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInsts, Exts,
+ Truncs, true);
}
/// \see promoteOperandForOther.
- static Value *zeroExtendOperandForOther(Instruction *Ext,
- TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts) {
- return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInsts, false);
+ static Value *
+ zeroExtendOperandForOther(Instruction *Ext, TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts,
+ unsigned &CreatedInsts,
+ SmallVectorImpl<Instruction *> *Exts,
+ SmallVectorImpl<Instruction *> *Truncs) {
+ return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInsts, Exts,
+ Truncs, false);
}
public:
/// Type for the utility function that promotes the operand of Ext.
typedef Value *(*Action)(Instruction *Ext, TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts);
+ InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
+ SmallVectorImpl<Instruction *> *Exts,
+ SmallVectorImpl<Instruction *> *Truncs);
/// \brief Given a sign/zero extend instruction \p Ext, return the approriate
/// action to promote the operand of \p Ext instead of using Ext.
/// \return NULL if no promotable action is possible with the current
Type *ConsideredExtType,
const InstrToOrigTy &PromotedInsts,
bool IsSExt) {
+ // The promotion helper does not know how to deal with vector types yet.
+ // To be able to fix that, we would need to fix the places where we
+ // statically extend, e.g., constants and such.
+ if (Inst->getType()->isVectorTy())
+ return false;
+
// We can always get through zext.
if (isa<ZExtInst>(Inst))
return true;
// Check if we can use this operand in the extension.
// If the type is larger than the result type of the extension,
// we cannot.
- if (OpndVal->getType()->getIntegerBitWidth() >
- ConsideredExtType->getIntegerBitWidth())
+ if (!OpndVal->getType()->isIntegerTy() ||
+ OpndVal->getType()->getIntegerBitWidth() >
+ ConsideredExtType->getIntegerBitWidth())
return false;
// If the operand of the truncate is not an instruction, we will not have
Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
llvm::Instruction *SExt, TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts) {
+ InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
+ SmallVectorImpl<Instruction *> *Exts,
+ SmallVectorImpl<Instruction *> *Truncs) {
// By construction, the operand of SExt is an instruction. Otherwise we cannot
// get through it and this method should not be called.
Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
// Check if the extension is still needed.
Instruction *ExtInst = dyn_cast<Instruction>(ExtVal);
- if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType())
+ if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) {
+ if (ExtInst && Exts)
+ Exts->push_back(ExtInst);
return ExtVal;
+ }
// At this point we have: ext ty opnd to ty.
// Reassign the uses of ExtInst to the opnd and remove ExtInst.
Value *TypePromotionHelper::promoteOperandForOther(
Instruction *Ext, TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts, bool IsSExt) {
+ InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
+ SmallVectorImpl<Instruction *> *Exts,
+ SmallVectorImpl<Instruction *> *Truncs, bool IsSExt) {
// By construction, the operand of Ext is an instruction. Otherwise we cannot
// get through it and this method should not be called.
Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0));
ITrunc->removeFromParent();
// Insert it just after the definition.
ITrunc->insertAfter(ExtOpnd);
+ if (Truncs)
+ Truncs->push_back(ITrunc);
}
TPT.replaceAllUsesWith(ExtOpnd, Trunc);
if (!ExtForOpnd) {
// If yes, create a new one.
DEBUG(dbgs() << "More operands to ext\n");
- ExtForOpnd =
- cast<Instruction>(IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
- : TPT.createZExt(Ext, Opnd, Ext->getType()));
+ Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
+ : TPT.createZExt(Ext, Opnd, Ext->getType());
+ if (!isa<Instruction>(ValForExtOpnd)) {
+ TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd);
+ continue;
+ }
+ ExtForOpnd = cast<Instruction>(ValForExtOpnd);
++CreatedInsts;
}
-
+ if (Exts)
+ Exts->push_back(ExtForOpnd);
TPT.setOperand(ExtForOpnd, 0, Opnd);
// Move the sign extension before the insertion point.
// The promotion is neutral but it may help folding the sign extension in
// loads for instance.
// Check that we did not create an illegal instruction.
- Instruction *PromotedInst = dyn_cast<Instruction>(PromotedOperand);
- if (!PromotedInst)
- return false;
- int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
- // If the ISDOpcode is undefined, it was undefined before the promotion.
- if (!ISDOpcode)
- return true;
- // Otherwise, check if the promoted instruction is legal or not.
- return TLI.isOperationLegalOrCustom(
- ISDOpcode, TLI.getValueType(PromotedInst->getType()));
+ return isPromotedInstructionLegal(TLI, PromotedOperand);
}
/// MatchOperationAddr - Given an instruction or constant expr, see if we can
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
TPT.getRestorationPoint();
unsigned CreatedInsts = 0;
- Value *PromotedOperand = TPH(Ext, TPT, PromotedInsts, CreatedInsts);
+ Value *PromotedOperand =
+ TPH(Ext, TPT, PromotedInsts, CreatedInsts, nullptr, nullptr);
// SExt has been moved away.
// Thus either it will be rematched later in the recursive calls or it is
// gone. Anyway, we must not fold it into the addressing mode at this point.
<< *MemoryInst << "\n");
if (SunkAddr->getType() != Addr->getType())
SunkAddr = Builder.CreateBitCast(SunkAddr, Addr->getType());
- } else if (AddrSinkUsingGEPs || (!AddrSinkUsingGEPs.getNumOccurrences() &&
- TM && TM->getSubtarget<TargetSubtargetInfo>().useAA())) {
+ } else if (AddrSinkUsingGEPs ||
+ (!AddrSinkUsingGEPs.getNumOccurrences() && TM &&
+ TM->getSubtargetImpl(*MemoryInst->getParent()->getParent())
+ ->useAA())) {
// By default, we use the GEP-based method when AA is used later. This
// prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrMode << " for "
return MadeChange;
}
+/// \brief Check if all the uses of \p Inst are equivalent (or free) zero or
+/// sign extensions.
+static bool hasSameExtUse(Instruction *Inst, const TargetLowering &TLI) {
+ assert(!Inst->use_empty() && "Input must have at least one use");
+ const Instruction *FirstUser = cast<Instruction>(*Inst->user_begin());
+ bool IsSExt = isa<SExtInst>(FirstUser);
+ Type *ExtTy = FirstUser->getType();
+ for (const User *U : Inst->users()) {
+ const Instruction *UI = cast<Instruction>(U);
+ if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI)))
+ return false;
+ Type *CurTy = UI->getType();
+ // Same input and output types: Same instruction after CSE.
+ if (CurTy == ExtTy)
+ continue;
+
+ // If IsSExt is true, we are in this situation:
+ // a = Inst
+ // b = sext ty1 a to ty2
+ // c = sext ty1 a to ty3
+ // Assuming ty2 is shorter than ty3, this could be turned into:
+ // a = Inst
+ // b = sext ty1 a to ty2
+ // c = sext ty2 b to ty3
+ // However, the last sext is not free.
+ if (IsSExt)
+ return false;
+
+ // This is a ZExt, maybe this is free to extend from one type to another.
+ // In that case, we would not account for a different use.
+ Type *NarrowTy;
+ Type *LargeTy;
+ if (ExtTy->getScalarType()->getIntegerBitWidth() >
+ CurTy->getScalarType()->getIntegerBitWidth()) {
+ NarrowTy = CurTy;
+ LargeTy = ExtTy;
+ } else {
+ NarrowTy = ExtTy;
+ LargeTy = CurTy;
+ }
+
+ if (!TLI.isZExtFree(NarrowTy, LargeTy))
+ return false;
+ }
+ // All uses are the same or can be derived from one another for free.
+ return true;
+}
+
+/// \brief Try to form ExtLd by promoting \p Exts until they reach a
+/// load instruction.
+/// If an ext(load) can be formed, it is returned via \p LI for the load
+/// and \p Inst for the extension.
+/// Otherwise LI == nullptr and Inst == nullptr.
+/// When some promotion happened, \p TPT contains the proper state to
+/// revert them.
+///
+/// \return true when promoting was necessary to expose the ext(load)
+/// opportunity, false otherwise.
+///
+/// Example:
+/// \code
+/// %ld = load i32* %addr
+/// %add = add nuw i32 %ld, 4
+/// %zext = zext i32 %add to i64
+/// \endcode
+/// =>
+/// \code
+/// %ld = load i32* %addr
+/// %zext = zext i32 %ld to i64
+/// %add = add nuw i64 %zext, 4
+/// \encode
+/// Thanks to the promotion, we can match zext(load i32*) to i64.
+bool CodeGenPrepare::ExtLdPromotion(TypePromotionTransaction &TPT,
+ LoadInst *&LI, Instruction *&Inst,
+ const SmallVectorImpl<Instruction *> &Exts,
+ unsigned CreatedInsts = 0) {
+ // Iterate over all the extensions to see if one form an ext(load).
+ for (auto I : Exts) {
+ // Check if we directly have ext(load).
+ if ((LI = dyn_cast<LoadInst>(I->getOperand(0)))) {
+ Inst = I;
+ // No promotion happened here.
+ return false;
+ }
+ // Check whether or not we want to do any promotion.
+ if (!TLI || !TLI->enableExtLdPromotion() || DisableExtLdPromotion)
+ continue;
+ // Get the action to perform the promotion.
+ TypePromotionHelper::Action TPH = TypePromotionHelper::getAction(
+ I, InsertedTruncsSet, *TLI, PromotedInsts);
+ // Check if we can promote.
+ if (!TPH)
+ continue;
+ // Save the current state.
+ TypePromotionTransaction::ConstRestorationPt LastKnownGood =
+ TPT.getRestorationPoint();
+ SmallVector<Instruction *, 4> NewExts;
+ unsigned NewCreatedInsts = 0;
+ // Promote.
+ Value *PromotedVal =
+ TPH(I, TPT, PromotedInsts, NewCreatedInsts, &NewExts, nullptr);
+ assert(PromotedVal &&
+ "TypePromotionHelper should have filtered out those cases");
+
+ // We would be able to merge only one extension in a load.
+ // Therefore, if we have more than 1 new extension we heuristically
+ // cut this search path, because it means we degrade the code quality.
+ // With exactly 2, the transformation is neutral, because we will merge
+ // one extension but leave one. However, we optimistically keep going,
+ // because the new extension may be removed too.
+ unsigned TotalCreatedInsts = CreatedInsts + NewCreatedInsts;
+ if (!StressExtLdPromotion &&
+ (TotalCreatedInsts > 1 ||
+ !isPromotedInstructionLegal(*TLI, PromotedVal))) {
+ // The promotion is not profitable, rollback to the previous state.
+ TPT.rollback(LastKnownGood);
+ continue;
+ }
+ // The promotion is profitable.
+ // Check if it exposes an ext(load).
+ (void)ExtLdPromotion(TPT, LI, Inst, NewExts, TotalCreatedInsts);
+ if (LI && (StressExtLdPromotion || NewCreatedInsts == 0 ||
+ // If we have created a new extension, i.e., now we have two
+ // extensions. We must make sure one of them is merged with
+ // the load, otherwise we may degrade the code quality.
+ (LI->hasOneUse() || hasSameExtUse(LI, *TLI))))
+ // Promotion happened.
+ return true;
+ // If this does not help to expose an ext(load) then, rollback.
+ TPT.rollback(LastKnownGood);
+ }
+ // None of the extension can form an ext(load).
+ LI = nullptr;
+ Inst = nullptr;
+ return false;
+}
+
/// MoveExtToFormExtLoad - Move a zext or sext fed by a load into the same
/// basic block as the load, unless conditions are unfavorable. This allows
/// SelectionDAG to fold the extend into the load.
+/// \p I[in/out] the extension may be modified during the process if some
+/// promotions apply.
///
-bool CodeGenPrepare::MoveExtToFormExtLoad(Instruction *I) {
+bool CodeGenPrepare::MoveExtToFormExtLoad(Instruction *&I) {
+ // Try to promote a chain of computation if it allows to form
+ // an extended load.
+ TypePromotionTransaction TPT;
+ TypePromotionTransaction::ConstRestorationPt LastKnownGood =
+ TPT.getRestorationPoint();
+ SmallVector<Instruction *, 1> Exts;
+ Exts.push_back(I);
// Look for a load being extended.
- LoadInst *LI = dyn_cast<LoadInst>(I->getOperand(0));
- if (!LI) return false;
+ LoadInst *LI = nullptr;
+ Instruction *OldExt = I;
+ bool HasPromoted = ExtLdPromotion(TPT, LI, I, Exts);
+ if (!LI || !I) {
+ assert(!HasPromoted && !LI && "If we did not match any load instruction "
+ "the code must remain the same");
+ I = OldExt;
+ return false;
+ }
// If they're already in the same block, there's nothing to do.
- if (LI->getParent() == I->getParent())
+ // Make the cheap checks first if we did not promote.
+ // If we promoted, we need to check if it is indeed profitable.
+ if (!HasPromoted && LI->getParent() == I->getParent())
return false;
EVT VT = TLI->getValueType(I->getType());
// isn't worthwhile.
if (!LI->hasOneUse() && TLI &&
(TLI->isTypeLegal(LoadVT) || !TLI->isTypeLegal(VT)) &&
- !TLI->isTruncateFree(I->getType(), LI->getType()))
+ !TLI->isTruncateFree(I->getType(), LI->getType())) {
+ I = OldExt;
+ TPT.rollback(LastKnownGood);
return false;
+ }
// Check whether the target supports casts folded into loads.
unsigned LType;
assert(isa<SExtInst>(I) && "Unexpected ext type!");
LType = ISD::SEXTLOAD;
}
- if (TLI && !TLI->isLoadExtLegal(LType, LoadVT))
+ if (TLI && !TLI->isLoadExtLegal(LType, VT, LoadVT)) {
+ I = OldExt;
+ TPT.rollback(LastKnownGood);
return false;
+ }
// Move the extend into the same block as the load, so that SelectionDAG
// can fold it.
+ TPT.commit();
I->removeFromParent();
I->insertAfter(LI);
++NumExtsMoved;
isa<UndefValue>(Val) ||
canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo()));
} else
- assert(0 && "Did you modified shouldPromote and forgot to update this?");
+ llvm_unreachable("Did you modified shouldPromote and forgot to update "
+ "this?");
ToBePromoted->setOperand(U.getOperandNo(), NewVal);
}
Transition->removeFromParent();
Transition->setOperand(getTransitionOriginalValueIdx(), ToBePromoted);
}
+// See if we can speculate calls to intrinsic cttz/ctlz.
+//
+// Example:
+// entry:
+// ...
+// %cmp = icmp eq i64 %val, 0
+// br i1 %cmp, label %end.bb, label %then.bb
+//
+// then.bb:
+// %c = tail call i64 @llvm.cttz.i64(i64 %val, i1 true)
+// br label %EndBB
+//
+// end.bb:
+// %cond = phi i64 [ %c, %then.bb ], [ 64, %entry ]
+//
+// ==>
+//
+// entry:
+// ...
+// %c = tail call i64 @llvm.cttz.i64(i64 %val, i1 false)
+//
+static bool OptimizeBranchInst(BranchInst *BrInst, const TargetLowering &TLI) {
+ assert(BrInst->isConditional() && "Expected a conditional branch!");
+ BasicBlock *ThenBB = BrInst->getSuccessor(1);
+ BasicBlock *EndBB = BrInst->getSuccessor(0);
+
+ // See if ThenBB contains only one instruction (excluding the
+ // terminator and DbgInfoIntrinsic calls).
+ IntrinsicInst *II = nullptr;
+ CastInst *CI = nullptr;
+ for (BasicBlock::iterator I = ThenBB->begin(),
+ E = std::prev(ThenBB->end()); I != E; ++I) {
+ // Skip debug info.
+ if (isa<DbgInfoIntrinsic>(I))
+ continue;
+
+ // Check if this is a zero extension or a truncate of a previously
+ // matched call to intrinsic cttz/ctlz.
+ if (II) {
+ // Early exit if we already found a "free" zero extend/truncate.
+ if (CI)
+ return false;
+
+ Type *SrcTy = II->getType();
+ Type *DestTy = I->getType();
+ Value *V;
+
+ if (match(cast<Instruction>(I), m_ZExt(m_Value(V))) && V == II) {
+ // Speculate this zero extend only if it is "free" for the target.
+ if (TLI.isZExtFree(SrcTy, DestTy)) {
+ CI = cast<CastInst>(I);
+ continue;
+ }
+ } else if (match(cast<Instruction>(I), m_Trunc(m_Value(V))) && V == II) {
+ // Speculate this truncate only if it is "free" for the target.
+ if (TLI.isTruncateFree(SrcTy, DestTy)) {
+ CI = cast<CastInst>(I);
+ continue;
+ }
+ } else {
+ // Avoid speculating more than one instruction.
+ return false;
+ }
+ }
+
+ // See if this is a call to intrinsic cttz/ctlz.
+ if (match(cast<Instruction>(I), m_Intrinsic<Intrinsic::cttz>())) {
+ // Avoid speculating expensive intrinsic calls.
+ if (!TLI.isCheapToSpeculateCttz())
+ return false;
+ }
+ else if (match(cast<Instruction>(I), m_Intrinsic<Intrinsic::ctlz>())) {
+ // Avoid speculating expensive intrinsic calls.
+ if (!TLI.isCheapToSpeculateCtlz())
+ return false;
+ } else
+ return false;
+
+ II = cast<IntrinsicInst>(I);
+ }
+
+ // Look for PHI nodes with 'II' as the incoming value from 'ThenBB'.
+ BasicBlock *EntryBB = BrInst->getParent();
+ for (BasicBlock::iterator I = EndBB->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I) {
+ Value *ThenV = PN->getIncomingValueForBlock(ThenBB);
+ Value *OrigV = PN->getIncomingValueForBlock(EntryBB);
+
+ if (!OrigV)
+ return false;
+
+ if (ThenV != II && (!CI || ThenV != CI))
+ return false;
+
+ if (ConstantInt *CInt = dyn_cast<ConstantInt>(OrigV)) {
+ unsigned BitWidth = II->getType()->getIntegerBitWidth();
+
+ // Don't try to simplify this phi node if 'ThenV' is a cttz/ctlz
+ // intrinsic call, but 'OrigV' is not equal to the 'size-of' in bits
+ // of the value in input to the cttz/ctlz.
+ if (CInt->getValue() != BitWidth)
+ return false;
+
+ // Hoist the call to cttz/ctlz from ThenBB into EntryBB.
+ EntryBB->getInstList().splice(BrInst, ThenBB->getInstList(),
+ ThenBB->begin(), std::prev(ThenBB->end()));
+
+ // Update PN setting ThenV as the incoming value from both 'EntryBB'
+ // and 'ThenBB'. Eventually, method 'OptimizeInst' will fold this
+ // phi node if all the incoming values are the same.
+ PN->setIncomingValue(PN->getBasicBlockIndex(EntryBB), ThenV);
+ PN->setIncomingValue(PN->getBasicBlockIndex(ThenBB), ThenV);
+
+ // Clear the 'undef on zero' flag of the cttz/ctlz intrinsic call.
+ if (cast<ConstantInt>(II->getArgOperand(1))->isOne()) {
+ Type *Ty = II->getArgOperand(0)->getType();
+ Value *Args[] = { II->getArgOperand(0),
+ ConstantInt::getFalse(II->getContext()) };
+ Module *M = EntryBB->getParent()->getParent();
+ Value *IF = Intrinsic::getDeclaration(M, II->getIntrinsicID(), Ty);
+ IRBuilder<> Builder(II);
+ Instruction *NewI = Builder.CreateCall(IF, Args);
+
+ // Replace the old call to cttz/ctlz.
+ II->replaceAllUsesWith(NewI);
+ II->eraseFromParent();
+ }
+
+ // Update BrInst condition so that the branch to EndBB is always taken.
+ // Later on, method 'ConstantFoldTerminator' will simplify this branch
+ // replacing it with a direct branch to 'EndBB'.
+ // As a side effect, CodeGenPrepare will attempt to simplify the control
+ // flow graph by deleting basic block 'ThenBB' and merging 'EntryBB' into
+ // 'EndBB' (calling method 'EliminateFallThrough').
+ BrInst->setCondition(ConstantInt::getTrue(BrInst->getContext()));
+ return true;
+ }
+ }
+
+ return false;
+}
+
/// Some targets can do store(extractelement) with one instruction.
/// Try to push the extractelement towards the stores when the target
/// has this feature and this is profitable.
return false;
}
-bool CodeGenPrepare::OptimizeInst(Instruction *I) {
+bool CodeGenPrepare::OptimizeInst(Instruction *I, bool& ModifiedDT) {
if (PHINode *P = dyn_cast<PHINode>(I)) {
// It is possible for very late stage optimizations (such as SimplifyCFG)
// to introduce PHI nodes too late to be cleaned up. If we detect such a
GEPI->replaceAllUsesWith(NC);
GEPI->eraseFromParent();
++NumGEPsElim;
- OptimizeInst(NC);
+ OptimizeInst(NC, ModifiedDT);
return true;
}
return false;
}
if (CallInst *CI = dyn_cast<CallInst>(I))
- return OptimizeCallInst(CI);
+ return OptimizeCallInst(CI, ModifiedDT);
if (SelectInst *SI = dyn_cast<SelectInst>(I))
return OptimizeSelectInst(SI);
if (isa<ExtractElementInst>(I))
return OptimizeExtractElementInst(I);
+ if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
+ if (TLI && BI->isConditional() && BI->getCondition()->hasOneUse()) {
+ // Check if the branch condition compares a value agaist zero.
+ if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) {
+ if (ICI->getPredicate() == ICmpInst::ICMP_EQ &&
+ match(ICI->getOperand(1), m_Zero())) {
+ BasicBlock *ThenBB = BI->getSuccessor(1);
+ BasicBlock *EndBB = BI->getSuccessor(0);
+
+ // Check if ThenBB is only reachable from this basic block; also,
+ // check if EndBB has more than one predecessor.
+ if (ThenBB->getSinglePredecessor() &&
+ !EndBB->getSinglePredecessor()) {
+ TerminatorInst *TI = ThenBB->getTerminator();
+
+ if (TI->getNumSuccessors() == 1 && TI->getSuccessor(0) == EndBB &&
+ // Try to speculate calls to intrinsic cttz/ctlz from 'ThenBB'.
+ OptimizeBranchInst(BI, *TLI)) {
+ ModifiedDT = true;
+ return true;
+ }
+ }
+ }
+ }
+ }
+ return false;
+ }
+
return false;
}
// In this pass we look for GEP and cast instructions that are used
// across basic blocks and rewrite them to improve basic-block-at-a-time
// selection.
-bool CodeGenPrepare::OptimizeBlock(BasicBlock &BB) {
+bool CodeGenPrepare::OptimizeBlock(BasicBlock &BB, bool& ModifiedDT) {
SunkAddrs.clear();
bool MadeChange = false;
CurInstIterator = BB.begin();
- while (CurInstIterator != BB.end())
- MadeChange |= OptimizeInst(CurInstIterator++);
-
+ while (CurInstIterator != BB.end()) {
+ MadeChange |= OptimizeInst(CurInstIterator++, ModifiedDT);
+ if (ModifiedDT)
+ return true;
+ }
MadeChange |= DupRetToEnableTailCallOpts(&BB);
return MadeChange;
// find a node corresponding to the value.
bool CodeGenPrepare::PlaceDbgValues(Function &F) {
bool MadeChange = false;
- for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
+ for (BasicBlock &BB : F) {
Instruction *PrevNonDbgInst = nullptr;
- for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
- Instruction *Insn = BI; ++BI;
+ for (BasicBlock::iterator BI = BB.begin(), BE = BB.end(); BI != BE;) {
+ Instruction *Insn = BI++;
DbgValueInst *DVI = dyn_cast<DbgValueInst>(Insn);
// Leave dbg.values that refer to an alloca alone. These
// instrinsics describe the address of a variable (= the alloca)
return MadeChange;
}
+/// \brief Retrieve the probabilities of a conditional branch. Returns true on
+/// success, or returns false if no or invalid metadata was found.
+static bool extractBranchMetadata(BranchInst *BI,
+ uint64_t &ProbTrue, uint64_t &ProbFalse) {
+ assert(BI->isConditional() &&
+ "Looking for probabilities on unconditional branch?");
+ auto *ProfileData = BI->getMetadata(LLVMContext::MD_prof);
+ if (!ProfileData || ProfileData->getNumOperands() != 3)
+ return false;
+
+ const auto *CITrue =
+ mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(1));
+ const auto *CIFalse =
+ mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2));
+ if (!CITrue || !CIFalse)
+ return false;
+
+ ProbTrue = CITrue->getValue().getZExtValue();
+ ProbFalse = CIFalse->getValue().getZExtValue();
+
+ return true;
+}
+
/// \brief Scale down both weights to fit into uint32_t.
static void scaleWeights(uint64_t &NewTrue, uint64_t &NewFalse) {
uint64_t NewMax = (NewTrue > NewFalse) ? NewTrue : NewFalse;
continue;
unsigned Opc;
- Instruction *Cond1, *Cond2;
- if (match(LogicOp, m_And(m_OneUse(m_Instruction(Cond1)),
- m_OneUse(m_Instruction(Cond2)))))
+ Value *Cond1, *Cond2;
+ if (match(LogicOp, m_And(m_OneUse(m_Value(Cond1)),
+ m_OneUse(m_Value(Cond2)))))
Opc = Instruction::And;
- else if (match(LogicOp, m_Or(m_OneUse(m_Instruction(Cond1)),
- m_OneUse(m_Instruction(Cond2)))))
+ else if (match(LogicOp, m_Or(m_OneUse(m_Value(Cond1)),
+ m_OneUse(m_Value(Cond2)))))
Opc = Instruction::Or;
else
continue;
auto *Br1 = cast<BranchInst>(BB.getTerminator());
Br1->setCondition(Cond1);
LogicOp->eraseFromParent();
- Cond2->removeFromParent();
+
// Depending on the conditon we have to either replace the true or the false
// successor of the original branch instruction.
if (Opc == Instruction::And)
// Fill in the new basic block.
auto *Br2 = IRBuilder<>(TmpBB).CreateCondBr(Cond2, TBB, FBB);
- Cond2->insertBefore(Br2);
+ if (auto *I = dyn_cast<Instruction>(Cond2)) {
+ I->removeFromParent();
+ I->insertBefore(Br2);
+ }
// Update PHI nodes in both successors. The original BB needs to be
// replaced in one succesor's PHI nodes, because the branch comes now from
// Another choice is to assume TrueProb for BB1 equals to TrueProb for
// TmpBB, but the math is more complicated.
uint64_t TrueWeight, FalseWeight;
- if (Br1->getBranchWeights(TrueWeight, FalseWeight)) {
+ if (extractBranchMetadata(Br1, TrueWeight, FalseWeight)) {
uint64_t NewTrueWeight = TrueWeight;
uint64_t NewFalseWeight = TrueWeight + 2 * FalseWeight;
scaleWeights(NewTrueWeight, NewFalseWeight);
// assumes that
// FalseProb for BB1 == TrueProb for BB1 * FalseProb for TmpBB.
uint64_t TrueWeight, FalseWeight;
- if (Br1->getBranchWeights(TrueWeight, FalseWeight)) {
+ if (extractBranchMetadata(Br1, TrueWeight, FalseWeight)) {
uint64_t NewTrueWeight = 2 * TrueWeight + FalseWeight;
uint64_t NewFalseWeight = FalseWeight;
scaleWeights(NewTrueWeight, NewFalseWeight);
projects / oota-llvm.git / blobdiff