CodeGenPrepare.cpp [plain text]
#define DEBUG_TYPE "codegenprepare"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ProfileInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Transforms/Utils/AddrModeMatcher.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/PatternMatch.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/IRBuilder.h"
#include "llvm/Support/ValueHandle.h"
using namespace llvm;
using namespace llvm::PatternMatch;
STATISTIC(NumBlocksElim, "Number of blocks eliminated");
STATISTIC(NumPHIsElim, "Number of trivial PHIs eliminated");
STATISTIC(NumGEPsElim, "Number of GEPs converted to casts");
STATISTIC(NumCmpUses, "Number of uses of Cmp expressions replaced with uses of "
"sunken Cmps");
STATISTIC(NumCastUses, "Number of uses of Cast expressions replaced with uses "
"of sunken Casts");
STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "
"computations were sunk");
STATISTIC(NumExtsMoved, "Number of [s|z]ext instructions combined with loads");
STATISTIC(NumExtUses, "Number of uses of [s|z]ext instructions optimized");
STATISTIC(NumRetsDup, "Number of return instructions duplicated");
STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved");
static cl::opt<bool> DisableBranchOpts(
"disable-cgp-branch-opts", cl::Hidden, cl::init(false),
cl::desc("Disable branch optimizations in CodeGenPrepare"));
static cl::opt<bool> DisableDeleteDeadBlocks(
"disable-cgp-delete-dead-blocks", cl::Hidden, cl::init(false),
cl::desc("Disable deleting dead blocks in CodeGenPrepare"));
namespace {
class CodeGenPrepare : public FunctionPass {
const TargetLowering *TLI;
const TargetLibraryInfo *TLInfo;
DominatorTree *DT;
ProfileInfo *PFI;
BasicBlock::iterator CurInstIterator;
DenseMap<Value*, Value*> SunkAddrs;
bool ModifiedDT;
public:
static char ID; explicit CodeGenPrepare(const TargetLowering *tli = 0)
: FunctionPass(ID), TLI(tli) {
initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
}
bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<DominatorTree>();
AU.addPreserved<ProfileInfo>();
AU.addRequired<TargetLibraryInfo>();
}
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 OptimizeMemoryInst(Instruction *I, Value *Addr, Type *AccessTy);
bool OptimizeInlineAsmInst(CallInst *CS);
bool OptimizeCallInst(CallInst *CI);
bool MoveExtToFormExtLoad(Instruction *I);
bool OptimizeExtUses(Instruction *I);
bool DupRetToEnableTailCallOpts(ReturnInst *RI);
bool PlaceDbgValues(Function &F);
};
}
char CodeGenPrepare::ID = 0;
INITIALIZE_PASS_BEGIN(CodeGenPrepare, "codegenprepare",
"Optimize for code generation", false, false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
INITIALIZE_PASS_END(CodeGenPrepare, "codegenprepare",
"Optimize for code generation", false, false)
FunctionPass *llvm::createCodeGenPreparePass(const TargetLowering *TLI) {
return new CodeGenPrepare(TLI);
}
bool CodeGenPrepare::runOnFunction(Function &F) {
bool EverMadeChange = false;
ModifiedDT = false;
TLInfo = &getAnalysis<TargetLibraryInfo>();
DT = getAnalysisIfAvailable<DominatorTree>();
PFI = getAnalysisIfAvailable<ProfileInfo>();
EverMadeChange |= EliminateMostlyEmptyBlocks(F);
EverMadeChange |= PlaceDbgValues(F);
bool MadeChange = true;
while (MadeChange) {
MadeChange = false;
for (Function::iterator I = F.begin(), E = F.end(); I != E; ) {
BasicBlock *BB = I++;
MadeChange |= OptimizeBlock(*BB);
}
EverMadeChange |= MadeChange;
}
SunkAddrs.clear();
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);
if (!MadeChange) continue;
for (SmallVectorImpl<BasicBlock*>::iterator
II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
if (pred_begin(*II) == pred_end(*II))
WorkList.insert(*II);
}
if (!DisableDeleteDeadBlocks)
for (SmallPtrSet<BasicBlock*, 8>::iterator
I = WorkList.begin(), E = WorkList.end(); I != E; ++I)
DeleteDeadBlock(*I);
if (MadeChange)
ModifiedDT = true;
EverMadeChange |= MadeChange;
}
if (ModifiedDT && DT)
DT->DT->recalculate(F);
return EverMadeChange;
}
bool CodeGenPrepare::EliminateMostlyEmptyBlocks(Function &F) {
bool MadeChange = false;
for (Function::iterator I = ++F.begin(), E = F.end(); I != E; ) {
BasicBlock *BB = I++;
BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
if (!BI || !BI->isUnconditional())
continue;
BasicBlock::iterator BBI = BI;
if (BBI != BB->begin()) {
--BBI;
while (isa<DbgInfoIntrinsic>(BBI)) {
if (BBI == BB->begin())
break;
--BBI;
}
if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI))
continue;
}
BasicBlock *DestBB = BI->getSuccessor(0);
if (DestBB == BB)
continue;
if (!CanMergeBlocks(BB, DestBB))
continue;
EliminateMostlyEmptyBlock(BB);
MadeChange = true;
}
return MadeChange;
}
bool CodeGenPrepare::CanMergeBlocks(const BasicBlock *BB,
const BasicBlock *DestBB) const {
BasicBlock::const_iterator BBI = BB->begin();
while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
for (Value::const_use_iterator UI = PN->use_begin(), E = PN->use_end();
UI != E; ++UI) {
const Instruction *User = cast<Instruction>(*UI);
if (User->getParent() != DestBB || !isa<PHINode>(User))
return false;
if (User->getParent() == DestBB) {
if (const PHINode *UPN = dyn_cast<PHINode>(User))
for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
if (Insn && Insn->getParent() == BB &&
Insn->getParent() != UPN->getIncomingBlock(I))
return false;
}
}
}
}
const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
if (!DestBBPN) return true;
SmallPtrSet<const BasicBlock*, 16> BBPreds;
if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
BBPreds.insert(BBPN->getIncomingBlock(i));
} else {
BBPreds.insert(pred_begin(BB), pred_end(BB));
}
for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
if (BBPreds.count(Pred)) { BBI = DestBB->begin();
while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
const Value *V1 = PN->getIncomingValueForBlock(Pred);
const Value *V2 = PN->getIncomingValueForBlock(BB);
if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
if (V2PN->getParent() == BB)
V2 = V2PN->getIncomingValueForBlock(Pred);
if (V1 != V2) return false;
}
}
}
return true;
}
void CodeGenPrepare::EliminateMostlyEmptyBlock(BasicBlock *BB) {
BranchInst *BI = cast<BranchInst>(BB->getTerminator());
BasicBlock *DestBB = BI->getSuccessor(0);
DEBUG(dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n" << *BB << *DestBB);
if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
if (SinglePred != DestBB) {
bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
MergeBasicBlockIntoOnlyPred(DestBB, this);
if (isEntry && BB != &BB->getParent()->getEntryBlock())
BB->moveBefore(&BB->getParent()->getEntryBlock());
DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
return;
}
}
PHINode *PN;
for (BasicBlock::iterator BBI = DestBB->begin();
(PN = dyn_cast<PHINode>(BBI)); ++BBI) {
Value *InVal = PN->removeIncomingValue(BB, false);
PHINode *InValPhi = dyn_cast<PHINode>(InVal);
if (InValPhi && InValPhi->getParent() == BB) {
for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
PN->addIncoming(InValPhi->getIncomingValue(i),
InValPhi->getIncomingBlock(i));
} else {
if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
PN->addIncoming(InVal, BBPN->getIncomingBlock(i));
} else {
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
PN->addIncoming(InVal, *PI);
}
}
}
BB->replaceAllUsesWith(DestBB);
if (DT && !ModifiedDT) {
BasicBlock *BBIDom = DT->getNode(BB)->getIDom()->getBlock();
BasicBlock *DestBBIDom = DT->getNode(DestBB)->getIDom()->getBlock();
BasicBlock *NewIDom = DT->findNearestCommonDominator(BBIDom, DestBBIDom);
DT->changeImmediateDominator(DestBB, NewIDom);
DT->eraseNode(BB);
}
if (PFI) {
PFI->replaceAllUses(BB, DestBB);
PFI->removeEdge(ProfileInfo::getEdge(BB, DestBB));
}
BB->eraseFromParent();
++NumBlocksElim;
DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
}
static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI){
EVT SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
EVT DstVT = TLI.getValueType(CI->getType());
if (SrcVT.isInteger() != DstVT.isInteger())
return false;
if (SrcVT.bitsLT(DstVT)) return false;
if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
TargetLowering::TypePromoteInteger)
SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
if (TLI.getTypeAction(CI->getContext(), DstVT) ==
TargetLowering::TypePromoteInteger)
DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
if (SrcVT != DstVT)
return false;
BasicBlock *DefBB = CI->getParent();
DenseMap<BasicBlock*, CastInst*> InsertedCasts;
bool MadeChange = false;
for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
UI != E; ) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
BasicBlock *UserBB = User->getParent();
if (PHINode *PN = dyn_cast<PHINode>(User)) {
UserBB = PN->getIncomingBlock(UI);
}
++UI;
if (UserBB == DefBB) continue;
CastInst *&InsertedCast = InsertedCasts[UserBB];
if (!InsertedCast) {
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
InsertedCast =
CastInst::Create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
InsertPt);
MadeChange = true;
}
TheUse = InsertedCast;
++NumCastUses;
}
if (CI->use_empty()) {
CI->eraseFromParent();
MadeChange = true;
}
return MadeChange;
}
static bool OptimizeCmpExpression(CmpInst *CI) {
BasicBlock *DefBB = CI->getParent();
DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
bool MadeChange = false;
for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
UI != E; ) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
++UI;
if (isa<PHINode>(User))
continue;
BasicBlock *UserBB = User->getParent();
if (UserBB == DefBB) continue;
CmpInst *&InsertedCmp = InsertedCmps[UserBB];
if (!InsertedCmp) {
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
InsertedCmp =
CmpInst::Create(CI->getOpcode(),
CI->getPredicate(), CI->getOperand(0),
CI->getOperand(1), "", InsertPt);
MadeChange = true;
}
TheUse = InsertedCmp;
++NumCmpUses;
}
if (CI->use_empty())
CI->eraseFromParent();
return MadeChange;
}
namespace {
class CodeGenPrepareFortifiedLibCalls : public SimplifyFortifiedLibCalls {
protected:
void replaceCall(Value *With) {
CI->replaceAllUsesWith(With);
CI->eraseFromParent();
}
bool isFoldable(unsigned SizeCIOp, unsigned, bool) const {
if (ConstantInt *SizeCI =
dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp)))
return SizeCI->isAllOnesValue();
return false;
}
};
}
bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
BasicBlock *BB = CI->getParent();
if (TLI && isa<InlineAsm>(CI->getCalledValue())) {
if (TLI->ExpandInlineAsm(CI)) {
CurInstIterator = BB->begin();
SunkAddrs.clear();
return true;
}
if (OptimizeInlineAsmInst(CI))
return true;
}
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);
WeakVH IterHandle(CurInstIterator);
ReplaceAndSimplifyAllUses(CI, RetVal, TLI ? TLI->getTargetData() : 0,
TLInfo, ModifiedDT ? 0 : DT);
if (IterHandle != CurInstIterator) {
CurInstIterator = BB->begin();
SunkAddrs.clear();
}
return true;
}
if (CI->getCalledFunction() == 0) return false;
const TargetData *TD = TLI ? TLI->getTargetData() : 0;
if (!TD) return false;
CodeGenPrepareFortifiedLibCalls Simplifier;
return Simplifier.fold(CI, TD);
}
bool CodeGenPrepare::DupRetToEnableTailCallOpts(ReturnInst *RI) {
if (!TLI)
return false;
Value *V = RI->getReturnValue();
PHINode *PN = V ? dyn_cast<PHINode>(V) : NULL;
if (V && !PN)
return false;
BasicBlock *BB = RI->getParent();
if (PN && PN->getParent() != BB)
return false;
const Function *F = BB->getParent();
Attributes CallerRetAttr = F->getAttributes().getRetAttributes();
if ((CallerRetAttr & Attribute::ZExt) || (CallerRetAttr & Attribute::SExt))
return false;
if (PN) {
BasicBlock::iterator BI = BB->begin();
do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
if (&*BI != RI)
return false;
} else {
BasicBlock::iterator BI = BB->begin();
while (isa<DbgInfoIntrinsic>(BI)) ++BI;
if (&*BI != RI)
return false;
}
SmallVector<CallInst*, 4> TailCalls;
if (PN) {
for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
CallInst *CI = dyn_cast<CallInst>(PN->getIncomingValue(I));
if (CI && CI->hasOneUse() && CI->getParent() == PN->getIncomingBlock(I) &&
TLI->mayBeEmittedAsTailCall(CI))
TailCalls.push_back(CI);
}
} else {
SmallPtrSet<BasicBlock*, 4> VisitedBBs;
for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
if (!VisitedBBs.insert(*PI))
continue;
BasicBlock::InstListType &InstList = (*PI)->getInstList();
BasicBlock::InstListType::reverse_iterator RI = InstList.rbegin();
BasicBlock::InstListType::reverse_iterator RE = InstList.rend();
do { ++RI; } while (RI != RE && isa<DbgInfoIntrinsic>(&*RI));
if (RI == RE)
continue;
CallInst *CI = dyn_cast<CallInst>(&*RI);
if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI))
TailCalls.push_back(CI);
}
}
bool Changed = false;
for (unsigned i = 0, e = TailCalls.size(); i != e; ++i) {
CallInst *CI = TailCalls[i];
CallSite CS(CI);
Attributes CalleeRetAttr = CS.getAttributes().getRetAttributes();
if ((CalleeRetAttr ^ CallerRetAttr) & ~Attribute::NoAlias)
continue;
BasicBlock *CallBB = CI->getParent();
BranchInst *BI = dyn_cast<BranchInst>(CallBB->getTerminator());
if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
continue;
(void)FoldReturnIntoUncondBranch(RI, BB, CallBB);
ModifiedDT = Changed = true;
++NumRetsDup;
}
if (Changed && pred_begin(BB) == pred_end(BB))
BB->eraseFromParent();
return Changed;
}
static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
if (Instruction *I = dyn_cast<Instruction>(V))
return I->getParent() != BB;
return false;
}
bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
Type *AccessTy) {
Value *Repl = Addr;
SmallVector<Value*, 8> worklist;
SmallPtrSet<Value*, 16> Visited;
worklist.push_back(Addr);
Value *Consensus = 0;
unsigned NumUsesConsensus = 0;
bool IsNumUsesConsensusValid = false;
SmallVector<Instruction*, 16> AddrModeInsts;
ExtAddrMode AddrMode;
while (!worklist.empty()) {
Value *V = worklist.back();
worklist.pop_back();
if (!Visited.insert(V)) {
Consensus = 0;
break;
}
if (PHINode *P = dyn_cast<PHINode>(V)) {
for (unsigned i = 0, e = P->getNumIncomingValues(); i != e; ++i)
worklist.push_back(P->getIncomingValue(i));
continue;
}
SmallVector<Instruction*, 16> NewAddrModeInsts;
ExtAddrMode NewAddrMode =
AddressingModeMatcher::Match(V, AccessTy, MemoryInst,
NewAddrModeInsts, *TLI);
if (!Consensus) {
Consensus = V;
AddrMode = NewAddrMode;
AddrModeInsts = NewAddrModeInsts;
continue;
} else if (NewAddrMode == AddrMode) {
if (!IsNumUsesConsensusValid) {
NumUsesConsensus = Consensus->getNumUses();
IsNumUsesConsensusValid = true;
}
unsigned NumUses = V->getNumUses();
if (NumUses > NumUsesConsensus) {
Consensus = V;
NumUsesConsensus = NumUses;
AddrModeInsts = NewAddrModeInsts;
}
continue;
}
Consensus = 0;
break;
}
if (!Consensus) return false;
bool AnyNonLocal = false;
for (unsigned i = 0, e = AddrModeInsts.size(); i != e; ++i) {
if (IsNonLocalValue(AddrModeInsts[i], MemoryInst->getParent())) {
AnyNonLocal = true;
break;
}
}
if (!AnyNonLocal) {
DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrMode << "\n");
return false;
}
IRBuilder<> Builder(MemoryInst);
Value *&SunkAddr = SunkAddrs[Addr];
if (SunkAddr) {
DEBUG(dbgs() << "CGP: Reusing nonlocal addrmode: " << AddrMode << " for "
<< *MemoryInst);
if (SunkAddr->getType() != Addr->getType())
SunkAddr = Builder.CreateBitCast(SunkAddr, Addr->getType());
} else {
DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrMode << " for "
<< *MemoryInst);
Type *IntPtrTy =
TLI->getTargetData()->getIntPtrType(AccessTy->getContext());
Value *Result = 0;
if (AddrMode.BaseReg) {
Value *V = AddrMode.BaseReg;
if (V->getType()->isPointerTy())
V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
if (V->getType() != IntPtrTy)
V = Builder.CreateIntCast(V, IntPtrTy, true, "sunkaddr");
Result = V;
}
if (AddrMode.Scale) {
Value *V = AddrMode.ScaledReg;
if (V->getType() == IntPtrTy) {
} else if (V->getType()->isPointerTy()) {
V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
} else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
cast<IntegerType>(V->getType())->getBitWidth()) {
V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
} else {
V = Builder.CreateSExt(V, IntPtrTy, "sunkaddr");
}
if (AddrMode.Scale != 1)
V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
"sunkaddr");
if (Result)
Result = Builder.CreateAdd(Result, V, "sunkaddr");
else
Result = V;
}
if (AddrMode.BaseGV) {
Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
if (Result)
Result = Builder.CreateAdd(Result, V, "sunkaddr");
else
Result = V;
}
if (AddrMode.BaseOffs) {
Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
if (Result)
Result = Builder.CreateAdd(Result, V, "sunkaddr");
else
Result = V;
}
if (Result == 0)
SunkAddr = Constant::getNullValue(Addr->getType());
else
SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr");
}
MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
if (Repl->use_empty()) {
WeakVH IterHandle(CurInstIterator);
BasicBlock *BB = CurInstIterator->getParent();
RecursivelyDeleteTriviallyDeadInstructions(Repl);
if (IterHandle != CurInstIterator) {
CurInstIterator = BB->begin();
SunkAddrs.clear();
} else {
SunkAddrs[Addr] = 0;
}
}
++NumMemoryInsts;
return true;
}
bool CodeGenPrepare::OptimizeInlineAsmInst(CallInst *CS) {
bool MadeChange = false;
TargetLowering::AsmOperandInfoVector
TargetConstraints = TLI->ParseConstraints(CS);
unsigned ArgNo = 0;
for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
TLI->ComputeConstraintToUse(OpInfo, SDValue());
if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
OpInfo.isIndirect) {
Value *OpVal = CS->getArgOperand(ArgNo++);
MadeChange |= OptimizeMemoryInst(CS, OpVal, OpVal->getType());
} else if (OpInfo.Type == InlineAsm::isInput)
ArgNo++;
}
return MadeChange;
}
bool CodeGenPrepare::MoveExtToFormExtLoad(Instruction *I) {
LoadInst *LI = dyn_cast<LoadInst>(I->getOperand(0));
if (!LI) return false;
if (LI->getParent() == I->getParent())
return false;
if (!LI->hasOneUse() &&
TLI && (TLI->isTypeLegal(TLI->getValueType(LI->getType())) ||
!TLI->isTypeLegal(TLI->getValueType(I->getType()))) &&
!TLI->isTruncateFree(I->getType(), LI->getType()))
return false;
unsigned LType;
if (isa<ZExtInst>(I))
LType = ISD::ZEXTLOAD;
else {
assert(isa<SExtInst>(I) && "Unexpected ext type!");
LType = ISD::SEXTLOAD;
}
if (TLI && !TLI->isLoadExtLegal(LType, TLI->getValueType(LI->getType())))
return false;
I->removeFromParent();
I->insertAfter(LI);
++NumExtsMoved;
return true;
}
bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
BasicBlock *DefBB = I->getParent();
Value *Src = I->getOperand(0);
if (Src->hasOneUse())
return false;
if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
return false;
if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
return false;
bool DefIsLiveOut = false;
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
BasicBlock *UserBB = User->getParent();
if (UserBB == DefBB) continue;
DefIsLiveOut = true;
break;
}
if (!DefIsLiveOut)
return false;
for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
BasicBlock *UserBB = User->getParent();
if (UserBB == DefBB) continue;
if (isa<PHINode>(User) || isa<LoadInst>(User) || isa<StoreInst>(User))
return false;
}
DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
bool MadeChange = false;
for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
UI != E; ++UI) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
BasicBlock *UserBB = User->getParent();
if (UserBB == DefBB) continue;
Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
if (!InsertedTrunc) {
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
InsertedTrunc = new TruncInst(I, Src->getType(), "", InsertPt);
}
TheUse = InsertedTrunc;
++NumExtUses;
MadeChange = true;
}
return MadeChange;
}
bool CodeGenPrepare::OptimizeInst(Instruction *I) {
if (PHINode *P = dyn_cast<PHINode>(I)) {
if (Value *V = SimplifyInstruction(P)) {
P->replaceAllUsesWith(V);
P->eraseFromParent();
++NumPHIsElim;
return true;
}
return false;
}
if (CastInst *CI = dyn_cast<CastInst>(I)) {
if (isa<Constant>(CI->getOperand(0)))
return false;
if (TLI && OptimizeNoopCopyExpression(CI, *TLI))
return true;
if (isa<ZExtInst>(I) || isa<SExtInst>(I)) {
bool MadeChange = MoveExtToFormExtLoad(I);
return MadeChange | OptimizeExtUses(I);
}
return false;
}
if (CmpInst *CI = dyn_cast<CmpInst>(I))
return OptimizeCmpExpression(CI);
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (TLI)
return OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
return false;
}
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
if (TLI)
return OptimizeMemoryInst(I, SI->getOperand(1),
SI->getOperand(0)->getType());
return false;
}
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
if (GEPI->hasAllZeroIndices()) {
Instruction *NC = new BitCastInst(GEPI->getOperand(0), GEPI->getType(),
GEPI->getName(), GEPI);
GEPI->replaceAllUsesWith(NC);
GEPI->eraseFromParent();
++NumGEPsElim;
OptimizeInst(NC);
return true;
}
return false;
}
if (CallInst *CI = dyn_cast<CallInst>(I))
return OptimizeCallInst(CI);
if (ReturnInst *RI = dyn_cast<ReturnInst>(I))
return DupRetToEnableTailCallOpts(RI);
return false;
}
bool CodeGenPrepare::OptimizeBlock(BasicBlock &BB) {
SunkAddrs.clear();
bool MadeChange = false;
CurInstIterator = BB.begin();
for (BasicBlock::iterator E = BB.end(); CurInstIterator != E; )
MadeChange |= OptimizeInst(CurInstIterator++);
return MadeChange;
}
bool CodeGenPrepare::PlaceDbgValues(Function &F) {
bool MadeChange = false;
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
Instruction *PrevNonDbgInst = NULL;
for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
Instruction *Insn = BI; ++BI;
DbgValueInst *DVI = dyn_cast<DbgValueInst>(Insn);
if (!DVI) {
PrevNonDbgInst = Insn;
continue;
}
Instruction *VI = dyn_cast_or_null<Instruction>(DVI->getValue());
if (VI && VI != PrevNonDbgInst && !VI->isTerminator()) {
DEBUG(dbgs() << "Moving Debug Value before :\n" << *DVI << ' ' << *VI);
DVI->removeFromParent();
if (isa<PHINode>(VI))
DVI->insertBefore(VI->getParent()->getFirstInsertionPt());
else
DVI->insertAfter(VI);
MadeChange = true;
++NumDbgValueMoved;
}
}
}
return MadeChange;
}