createMachineFunctionPrinterPass(raw_ostream &OS,
const std::string &Banner ="");
+ /// createCodeGenPreparePass - Transform the code to expose more pattern
+ /// matching during instruction selection.
+ FunctionPass *createCodeGenPreparePass(const TargetMachine *TM = 0);
+
/// MachineLoopInfo - This pass is a loop analysis pass.
extern char &MachineLoopInfoID;
//
FunctionPass *createConstantHoistingPass();
-//===----------------------------------------------------------------------===//
-//
-// CodeGenPrepare - This pass prepares a function for instruction selection.
-//
-FunctionPass *createCodeGenPreparePass(const TargetMachine *TM = 0);
-
//===----------------------------------------------------------------------===//
//
// InstructionNamer - Give any unnamed non-void instructions "tmp" names.
CalcSpillWeights.cpp
CallingConvLower.cpp
CodeGen.cpp
+ CodeGenPrepare.cpp
CriticalAntiDepBreaker.cpp
DFAPacketizer.cpp
DeadMachineInstructionElim.cpp
void llvm::initializeCodeGen(PassRegistry &Registry) {
initializeBasicTTIPass(Registry);
initializeBranchFolderPassPass(Registry);
+ initializeCodeGenPreparePass(Registry);
initializeDeadMachineInstructionElimPass(Registry);
initializeEarlyIfConverterPass(Registry);
initializeExpandPostRAPass(Registry);
--- /dev/null
+//===- CodeGenPrepare.cpp - Prepare a function for code generation --------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass munges the code in the input function to better prepare it for
+// SelectionDAG-based code generation. This works around limitations in it's
+// basic-block-at-a-time approach. It should eventually be removed.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "codegenprepare"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/ValueMap.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/Pass.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/ValueHandle.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Target/TargetLowering.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"
+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");
+STATISTIC(NumSelectsExpanded, "Number of selects turned into branches");
+
+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> DisableSelectToBranch(
+ "disable-cgp-select2branch", cl::Hidden, cl::init(false),
+ cl::desc("Disable select to branch conversion."));
+
+namespace {
+typedef SmallPtrSet<Instruction *, 16> SetOfInstrs;
+typedef DenseMap<Instruction *, Type *> InstrToOrigTy;
+
+ class CodeGenPrepare : public FunctionPass {
+ /// TLI - Keep a pointer of a TargetLowering to consult for determining
+ /// transformation profitability.
+ const TargetMachine *TM;
+ const TargetLowering *TLI;
+ const TargetLibraryInfo *TLInfo;
+ DominatorTree *DT;
+
+ /// CurInstIterator - As we scan instructions optimizing them, this is the
+ /// next instruction to optimize. Xforms that can invalidate this should
+ /// update it.
+ BasicBlock::iterator CurInstIterator;
+
+ /// Keeps track of non-local addresses that have been sunk into a block.
+ /// This allows us to avoid inserting duplicate code for blocks with
+ /// multiple load/stores of the same address.
+ ValueMap<Value*, Value*> SunkAddrs;
+
+ /// Keeps track of all truncates inserted for the current function.
+ SetOfInstrs InsertedTruncsSet;
+ /// Keeps track of the type of the related instruction before their
+ /// promotion for the current function.
+ InstrToOrigTy PromotedInsts;
+
+ /// ModifiedDT - If CFG is modified in anyway, dominator tree may need to
+ /// be updated.
+ bool ModifiedDT;
+
+ /// OptSize - True if optimizing for size.
+ bool OptSize;
+
+ public:
+ static char ID; // Pass identification, replacement for typeid
+ explicit CodeGenPrepare(const TargetMachine *TM = 0)
+ : FunctionPass(ID), TM(TM), TLI(0) {
+ initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
+ }
+ bool runOnFunction(Function &F);
+
+ const char *getPassName() const { return "CodeGen Prepare"; }
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addPreserved<DominatorTreeWrapperPass>();
+ AU.addRequired<TargetLibraryInfo>();
+ }
+
+ private:
+ bool EliminateFallThrough(Function &F);
+ 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 OptimizeSelectInst(SelectInst *SI);
+ bool OptimizeShuffleVectorInst(ShuffleVectorInst *SI);
+ bool DupRetToEnableTailCallOpts(BasicBlock *BB);
+ bool PlaceDbgValues(Function &F);
+ };
+}
+
+char CodeGenPrepare::ID = 0;
+static void *initializeCodeGenPreparePassOnce(PassRegistry &Registry) {
+ initializeTargetLibraryInfoPass(Registry);
+ PassInfo *PI = new PassInfo(
+ "Optimize for code generation", "codegenprepare", &CodeGenPrepare::ID,
+ PassInfo::NormalCtor_t(callDefaultCtor<CodeGenPrepare>), false, false,
+ PassInfo::TargetMachineCtor_t(callTargetMachineCtor<CodeGenPrepare>));
+ Registry.registerPass(*PI, true);
+ return PI;
+}
+
+void llvm::initializeCodeGenPreparePass(PassRegistry &Registry) {
+ CALL_ONCE_INITIALIZATION(initializeCodeGenPreparePassOnce)
+}
+
+FunctionPass *llvm::createCodeGenPreparePass(const TargetMachine *TM) {
+ return new CodeGenPrepare(TM);
+}
+
+bool CodeGenPrepare::runOnFunction(Function &F) {
+ bool EverMadeChange = false;
+ // Clear per function information.
+ InsertedTruncsSet.clear();
+ PromotedInsts.clear();
+
+ ModifiedDT = false;
+ if (TM) TLI = TM->getTargetLowering();
+ TLInfo = &getAnalysis<TargetLibraryInfo>();
+ DominatorTreeWrapperPass *DTWP =
+ getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+ DT = DTWP ? &DTWP->getDomTree() : 0;
+ OptSize = F.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
+ Attribute::OptimizeForSize);
+
+ /// This optimization identifies DIV instructions that can be
+ /// profitably bypassed and carried out with a shorter, faster divide.
+ if (!OptSize && TLI && TLI->isSlowDivBypassed()) {
+ const DenseMap<unsigned int, unsigned int> &BypassWidths =
+ TLI->getBypassSlowDivWidths();
+ for (Function::iterator I = F.begin(); I != F.end(); I++)
+ EverMadeChange |= bypassSlowDivision(F, I, BypassWidths);
+ }
+
+ // Eliminate blocks that contain only PHI nodes and an
+ // unconditional branch.
+ EverMadeChange |= EliminateMostlyEmptyBlocks(F);
+
+ // llvm.dbg.value is far away from the value then iSel may not be able
+ // handle it properly. iSel will drop llvm.dbg.value if it can not
+ // find a node corresponding to the value.
+ EverMadeChange |= PlaceDbgValues(F);
+
+ bool MadeChange = true;
+ while (MadeChange) {
+ MadeChange = false;
+ for (Function::iterator I = F.begin(); I != F.end(); ) {
+ 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);
+ }
+
+ // Delete the dead blocks and any of their dead successors.
+ MadeChange |= !WorkList.empty();
+ while (!WorkList.empty()) {
+ BasicBlock *BB = *WorkList.begin();
+ WorkList.erase(BB);
+ SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
+
+ DeleteDeadBlock(BB);
+
+ for (SmallVectorImpl<BasicBlock*>::iterator
+ II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
+ if (pred_begin(*II) == pred_end(*II))
+ WorkList.insert(*II);
+ }
+
+ // Merge pairs of basic blocks with unconditional branches, connected by
+ // a single edge.
+ if (EverMadeChange || MadeChange)
+ MadeChange |= EliminateFallThrough(F);
+
+ if (MadeChange)
+ ModifiedDT = true;
+ EverMadeChange |= MadeChange;
+ }
+
+ if (ModifiedDT && DT)
+ DT->recalculate(F);
+
+ return EverMadeChange;
+}
+
+/// EliminateFallThrough - Merge basic blocks which are connected
+/// by a single edge, where one of the basic blocks has a single successor
+/// pointing to the other basic block, which has a single predecessor.
+bool CodeGenPrepare::EliminateFallThrough(Function &F) {
+ bool Changed = false;
+ // Scan all of the blocks in the function, except for the entry block.
+ for (Function::iterator I = llvm::next(F.begin()), E = F.end(); I != E; ) {
+ BasicBlock *BB = I++;
+ // If the destination block has a single pred, then this is a trivial
+ // edge, just collapse it.
+ BasicBlock *SinglePred = BB->getSinglePredecessor();
+
+ // Don't merge if BB's address is taken.
+ if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue;
+
+ BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
+ if (Term && !Term->isConditional()) {
+ Changed = true;
+ DEBUG(dbgs() << "To merge:\n"<< *SinglePred << "\n\n\n");
+ // 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);
+
+ if (isEntry && BB != &BB->getParent()->getEntryBlock())
+ BB->moveBefore(&BB->getParent()->getEntryBlock());
+
+ // We have erased a block. Update the iterator.
+ I = BB;
+ }
+ }
+ return Changed;
+}
+
+/// EliminateMostlyEmptyBlocks - eliminate blocks that contain only PHI nodes,
+/// debug info directives, and an unconditional branch. Passes before isel
+/// (e.g. LSR/loopsimplify) often split edges in ways that are non-optimal for
+/// isel. Start by eliminating these blocks so we can split them the way we
+/// want them.
+bool CodeGenPrepare::EliminateMostlyEmptyBlocks(Function &F) {
+ bool MadeChange = false;
+ // Note that this intentionally skips the entry block.
+ for (Function::iterator I = llvm::next(F.begin()), E = F.end(); I != E; ) {
+ BasicBlock *BB = I++;
+
+ // If this block doesn't end with an uncond branch, ignore it.
+ BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
+ if (!BI || !BI->isUnconditional())
+ continue;
+
+ // If the instruction before the branch (skipping debug info) isn't a phi
+ // node, then other stuff is happening here.
+ 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;
+ }
+
+ // Do not break infinite loops.
+ BasicBlock *DestBB = BI->getSuccessor(0);
+ if (DestBB == BB)
+ continue;
+
+ if (!CanMergeBlocks(BB, DestBB))
+ continue;
+
+ EliminateMostlyEmptyBlock(BB);
+ MadeChange = true;
+ }
+ return MadeChange;
+}
+
+/// CanMergeBlocks - Return true if we can merge BB into DestBB if there is a
+/// single uncond branch between them, and BB contains no other non-phi
+/// instructions.
+bool CodeGenPrepare::CanMergeBlocks(const BasicBlock *BB,
+ const BasicBlock *DestBB) const {
+ // We only want to eliminate blocks whose phi nodes are used by phi nodes in
+ // the successor. If there are more complex condition (e.g. preheaders),
+ // don't mess around with them.
+ 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 is inside DestBB block and it is a PHINode then check
+ // incoming value. If incoming value is not from BB then this is
+ // a complex condition (e.g. preheaders) we want to avoid here.
+ 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;
+ }
+ }
+ }
+ }
+
+ // If BB and DestBB contain any common predecessors, then the phi nodes in BB
+ // and DestBB may have conflicting incoming values for the block. If so, we
+ // can't merge the block.
+ const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
+ if (!DestBBPN) return true; // no conflict.
+
+ // Collect the preds of BB.
+ SmallPtrSet<const BasicBlock*, 16> BBPreds;
+ if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
+ // It is faster to get preds from a PHI than with pred_iterator.
+ for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
+ BBPreds.insert(BBPN->getIncomingBlock(i));
+ } else {
+ BBPreds.insert(pred_begin(BB), pred_end(BB));
+ }
+
+ // Walk the preds of DestBB.
+ for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
+ BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
+ if (BBPreds.count(Pred)) { // Common predecessor?
+ BBI = DestBB->begin();
+ while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
+ const Value *V1 = PN->getIncomingValueForBlock(Pred);
+ const Value *V2 = PN->getIncomingValueForBlock(BB);
+
+ // If V2 is a phi node in BB, look up what the mapped value will be.
+ if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
+ if (V2PN->getParent() == BB)
+ V2 = V2PN->getIncomingValueForBlock(Pred);
+
+ // If there is a conflict, bail out.
+ if (V1 != V2) return false;
+ }
+ }
+ }
+
+ return true;
+}
+
+
+/// EliminateMostlyEmptyBlock - Eliminate a basic block that have only phi's and
+/// an unconditional branch in it.
+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 the destination block has a single pred, then this is a trivial edge,
+ // just collapse it.
+ if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
+ if (SinglePred != DestBB) {
+ // 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);
+
+ if (isEntry && BB != &BB->getParent()->getEntryBlock())
+ BB->moveBefore(&BB->getParent()->getEntryBlock());
+
+ DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
+ return;
+ }
+ }
+
+ // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
+ // to handle the new incoming edges it is about to have.
+ PHINode *PN;
+ for (BasicBlock::iterator BBI = DestBB->begin();
+ (PN = dyn_cast<PHINode>(BBI)); ++BBI) {
+ // Remove the incoming value for BB, and remember it.
+ Value *InVal = PN->removeIncomingValue(BB, false);
+
+ // Two options: either the InVal is a phi node defined in BB or it is some
+ // value that dominates BB.
+ PHINode *InValPhi = dyn_cast<PHINode>(InVal);
+ if (InValPhi && InValPhi->getParent() == BB) {
+ // Add all of the input values of the input PHI as inputs of this phi.
+ for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
+ PN->addIncoming(InValPhi->getIncomingValue(i),
+ InValPhi->getIncomingBlock(i));
+ } else {
+ // Otherwise, add one instance of the dominating value for each edge that
+ // we will be adding.
+ 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);
+ }
+ }
+ }
+
+ // The PHIs are now updated, change everything that refers to BB to use
+ // DestBB and remove BB.
+ 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);
+ }
+ BB->eraseFromParent();
+ ++NumBlocksElim;
+
+ DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
+}
+
+/// OptimizeNoopCopyExpression - If the specified cast instruction is a noop
+/// copy (e.g. it's casting from one pointer type to another, i32->i8 on PPC),
+/// sink it into user blocks to reduce the number of virtual
+/// registers that must be created and coalesced.
+///
+/// Return true if any changes are made.
+///
+static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI){
+ // If this is a noop copy,
+ EVT SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
+ EVT DstVT = TLI.getValueType(CI->getType());
+
+ // This is an fp<->int conversion?
+ if (SrcVT.isInteger() != DstVT.isInteger())
+ return false;
+
+ // If this is an extension, it will be a zero or sign extension, which
+ // isn't a noop.
+ if (SrcVT.bitsLT(DstVT)) return false;
+
+ // If these values will be promoted, find out what they will be promoted
+ // to. This helps us consider truncates on PPC as noop copies when they
+ // are.
+ 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, after promotion, these are the same types, this is a noop copy.
+ if (SrcVT != DstVT)
+ return false;
+
+ BasicBlock *DefBB = CI->getParent();
+
+ /// InsertedCasts - Only insert a cast in each block once.
+ 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);
+
+ // Figure out which BB this cast is used in. For PHI's this is the
+ // appropriate predecessor block.
+ BasicBlock *UserBB = User->getParent();
+ if (PHINode *PN = dyn_cast<PHINode>(User)) {
+ UserBB = PN->getIncomingBlock(UI);
+ }
+
+ // Preincrement use iterator so we don't invalidate it.
+ ++UI;
+
+ // If this user is in the same block as the cast, don't change the cast.
+ if (UserBB == DefBB) continue;
+
+ // If we have already inserted a cast into this block, use it.
+ CastInst *&InsertedCast = InsertedCasts[UserBB];
+
+ if (!InsertedCast) {
+ BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
+ InsertedCast =
+ CastInst::Create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
+ InsertPt);
+ MadeChange = true;
+ }
+
+ // Replace a use of the cast with a use of the new cast.
+ TheUse = InsertedCast;
+ ++NumCastUses;
+ }
+
+ // If we removed all uses, nuke the cast.
+ if (CI->use_empty()) {
+ CI->eraseFromParent();
+ MadeChange = true;
+ }
+
+ return MadeChange;
+}
+
+/// OptimizeCmpExpression - sink the given CmpInst into user blocks to reduce
+/// the number of virtual registers that must be created and coalesced. This is
+/// a clear win except on targets with multiple condition code registers
+/// (PowerPC), where it might lose; some adjustment may be wanted there.
+///
+/// Return true if any changes are made.
+static bool OptimizeCmpExpression(CmpInst *CI) {
+ BasicBlock *DefBB = CI->getParent();
+
+ /// InsertedCmp - Only insert a cmp in each block once.
+ 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);
+
+ // Preincrement use iterator so we don't invalidate it.
+ ++UI;
+
+ // Don't bother for PHI nodes.
+ if (isa<PHINode>(User))
+ continue;
+
+ // Figure out which BB this cmp is used in.
+ BasicBlock *UserBB = User->getParent();
+
+ // If this user is in the same block as the cmp, don't change the cmp.
+ if (UserBB == DefBB) continue;
+
+ // If we have already inserted a cmp into this block, use it.
+ 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;
+ }
+
+ // Replace a use of the cmp with a use of the new cmp.
+ TheUse = InsertedCmp;
+ ++NumCmpUses;
+ }
+
+ // If we removed all uses, nuke the cmp.
+ 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;
+ }
+};
+} // end anonymous namespace
+
+bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
+ BasicBlock *BB = CI->getParent();
+
+ // Lower inline assembly if we can.
+ // If we found an inline asm expession, and if the target knows how to
+ // lower it to normal LLVM code, do so now.
+ if (TLI && isa<InlineAsm>(CI->getCalledValue())) {
+ if (TLI->ExpandInlineAsm(CI)) {
+ // Avoid invalidating the iterator.
+ CurInstIterator = BB->begin();
+ // Avoid processing instructions out of order, which could cause
+ // reuse before a value is defined.
+ SunkAddrs.clear();
+ return true;
+ }
+ // Sink address computing for memory operands into the block.
+ if (OptimizeInlineAsmInst(CI))
+ 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);
+
+ replaceAndRecursivelySimplify(CI, RetVal, TLI ? TLI->getDataLayout() : 0,
+ TLInfo, ModifiedDT ? 0 : DT);
+
+ // 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;
+ }
+
+ 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;
+ }
+
+ // From here on out we're working with named functions.
+ if (CI->getCalledFunction() == 0) return false;
+
+ // We'll need DataLayout from here on out.
+ const DataLayout *TD = TLI ? TLI->getDataLayout() : 0;
+ if (!TD) return false;
+
+ // 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);
+}
+
+/// DupRetToEnableTailCallOpts - Look for opportunities to duplicate return
+/// instructions to the predecessor to enable tail call optimizations. The
+/// case it is currently looking for is:
+/// @code
+/// bb0:
+/// %tmp0 = tail call i32 @f0()
+/// br label %return
+/// bb1:
+/// %tmp1 = tail call i32 @f1()
+/// br label %return
+/// bb2:
+/// %tmp2 = tail call i32 @f2()
+/// br label %return
+/// return:
+/// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
+/// ret i32 %retval
+/// @endcode
+///
+/// =>
+///
+/// @code
+/// bb0:
+/// %tmp0 = tail call i32 @f0()
+/// ret i32 %tmp0
+/// bb1:
+/// %tmp1 = tail call i32 @f1()
+/// ret i32 %tmp1
+/// bb2:
+/// %tmp2 = tail call i32 @f2()
+/// ret i32 %tmp2
+/// @endcode
+bool CodeGenPrepare::DupRetToEnableTailCallOpts(BasicBlock *BB) {
+ if (!TLI)
+ return false;
+
+ ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator());
+ if (!RI)
+ return false;
+
+ PHINode *PN = 0;
+ BitCastInst *BCI = 0;
+ Value *V = RI->getReturnValue();
+ if (V) {
+ BCI = dyn_cast<BitCastInst>(V);
+ if (BCI)
+ V = BCI->getOperand(0);
+
+ PN = dyn_cast<PHINode>(V);
+ if (!PN)
+ return false;
+ }
+
+ if (PN && PN->getParent() != BB)
+ return false;
+
+ // It's not safe to eliminate the sign / zero extension of the return value.
+ // See llvm::isInTailCallPosition().
+ const Function *F = BB->getParent();
+ AttributeSet CallerAttrs = F->getAttributes();
+ if (CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt) ||
+ CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
+ return false;
+
+ // Make sure there are no instructions between the PHI and return, or that the
+ // return is the first instruction in the block.
+ if (PN) {
+ BasicBlock::iterator BI = BB->begin();
+ do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
+ if (&*BI == BCI)
+ // Also skip over the bitcast.
+ ++BI;
+ if (&*BI != RI)
+ return false;
+ } else {
+ BasicBlock::iterator BI = BB->begin();
+ while (isa<DbgInfoIntrinsic>(BI)) ++BI;
+ if (&*BI != RI)
+ return false;
+ }
+
+ /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
+ /// call.
+ SmallVector<CallInst*, 4> TailCalls;
+ if (PN) {
+ for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
+ CallInst *CI = dyn_cast<CallInst>(PN->getIncomingValue(I));
+ // Make sure the phi value is indeed produced by the tail call.
+ 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);
+
+ // Conservatively require the attributes of the call to match those of the
+ // return. Ignore noalias because it doesn't affect the call sequence.
+ AttributeSet CalleeAttrs = CS.getAttributes();
+ if (AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
+ removeAttribute(Attribute::NoAlias) !=
+ AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
+ removeAttribute(Attribute::NoAlias))
+ continue;
+
+ // Make sure the call instruction is followed by an unconditional branch to
+ // the return block.
+ BasicBlock *CallBB = CI->getParent();
+ BranchInst *BI = dyn_cast<BranchInst>(CallBB->getTerminator());
+ if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
+ continue;
+
+ // Duplicate the return into CallBB.
+ (void)FoldReturnIntoUncondBranch(RI, BB, CallBB);
+ ModifiedDT = Changed = true;
+ ++NumRetsDup;
+ }
+
+ // If we eliminated all predecessors of the block, delete the block now.
+ if (Changed && !BB->hasAddressTaken() && pred_begin(BB) == pred_end(BB))
+ BB->eraseFromParent();
+
+ return Changed;
+}
+
+//===----------------------------------------------------------------------===//
+// Memory Optimization
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExtAddrMode - This is an extended version of TargetLowering::AddrMode
+/// which holds actual Value*'s for register values.
+struct ExtAddrMode : public TargetLowering::AddrMode {
+ Value *BaseReg;
+ Value *ScaledReg;
+ ExtAddrMode() : BaseReg(0), ScaledReg(0) {}
+ void print(raw_ostream &OS) const;
+ void dump() const;
+
+ bool operator==(const ExtAddrMode& O) const {
+ return (BaseReg == O.BaseReg) && (ScaledReg == O.ScaledReg) &&
+ (BaseGV == O.BaseGV) && (BaseOffs == O.BaseOffs) &&
+ (HasBaseReg == O.HasBaseReg) && (Scale == O.Scale);
+ }
+};
+
+#ifndef NDEBUG
+static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
+ AM.print(OS);
+ return OS;
+}
+#endif
+
+void ExtAddrMode::print(raw_ostream &OS) const {
+ bool NeedPlus = false;
+ OS << "[";
+ if (BaseGV) {
+ OS << (NeedPlus ? " + " : "")
+ << "GV:";
+ BaseGV->printAsOperand(OS, /*PrintType=*/false);
+ NeedPlus = true;
+ }
+
+ if (BaseOffs)
+ OS << (NeedPlus ? " + " : "") << BaseOffs, NeedPlus = true;
+
+ if (BaseReg) {
+ OS << (NeedPlus ? " + " : "")
+ << "Base:";
+ BaseReg->printAsOperand(OS, /*PrintType=*/false);
+ NeedPlus = true;
+ }
+ if (Scale) {
+ OS << (NeedPlus ? " + " : "")
+ << Scale << "*";
+ ScaledReg->printAsOperand(OS, /*PrintType=*/false);
+ }
+
+ OS << ']';
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void ExtAddrMode::dump() const {
+ print(dbgs());
+ dbgs() << '\n';
+}
+#endif
+
+/// \brief This class provides transaction based operation on the IR.
+/// Every change made through this class is recorded in the internal state and
+/// can be undone (rollback) until commit is called.
+class TypePromotionTransaction {
+
+ /// \brief This represents the common interface of the individual transaction.
+ /// Each class implements the logic for doing one specific modification on
+ /// the IR via the TypePromotionTransaction.
+ class TypePromotionAction {
+ protected:
+ /// The Instruction modified.
+ Instruction *Inst;
+
+ public:
+ /// \brief Constructor of the action.
+ /// The constructor performs the related action on the IR.
+ TypePromotionAction(Instruction *Inst) : Inst(Inst) {}
+
+ virtual ~TypePromotionAction() {}
+
+ /// \brief Undo the modification done by this action.
+ /// When this method is called, the IR must be in the same state as it was
+ /// before this action was applied.
+ /// \pre Undoing the action works if and only if the IR is in the exact same
+ /// state as it was directly after this action was applied.
+ virtual void undo() = 0;
+
+ /// \brief Advocate every change made by this action.
+ /// When the results on the IR of the action are to be kept, it is important
+ /// to call this function, otherwise hidden information may be kept forever.
+ virtual void commit() {
+ // Nothing to be done, this action is not doing anything.
+ }
+ };
+
+ /// \brief Utility to remember the position of an instruction.
+ class InsertionHandler {
+ /// Position of an instruction.
+ /// Either an instruction:
+ /// - Is the first in a basic block: BB is used.
+ /// - Has a previous instructon: PrevInst is used.
+ union {
+ Instruction *PrevInst;
+ BasicBlock *BB;
+ } Point;
+ /// Remember whether or not the instruction had a previous instruction.
+ bool HasPrevInstruction;
+
+ public:
+ /// \brief Record the position of \p Inst.
+ InsertionHandler(Instruction *Inst) {
+ BasicBlock::iterator It = Inst;
+ HasPrevInstruction = (It != (Inst->getParent()->begin()));
+ if (HasPrevInstruction)
+ Point.PrevInst = --It;
+ else
+ Point.BB = Inst->getParent();
+ }
+
+ /// \brief Insert \p Inst at the recorded position.
+ void insert(Instruction *Inst) {
+ if (HasPrevInstruction) {
+ if (Inst->getParent())
+ Inst->removeFromParent();
+ Inst->insertAfter(Point.PrevInst);
+ } else {
+ Instruction *Position = Point.BB->getFirstInsertionPt();
+ if (Inst->getParent())
+ Inst->moveBefore(Position);
+ else
+ Inst->insertBefore(Position);
+ }
+ }
+ };
+
+ /// \brief Move an instruction before another.
+ class InstructionMoveBefore : public TypePromotionAction {
+ /// Original position of the instruction.
+ InsertionHandler Position;
+
+ public:
+ /// \brief Move \p Inst before \p Before.
+ InstructionMoveBefore(Instruction *Inst, Instruction *Before)
+ : TypePromotionAction(Inst), Position(Inst) {
+ DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Before << "\n");
+ Inst->moveBefore(Before);
+ }
+
+ /// \brief Move the instruction back to its original position.
+ void undo() {
+ DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n");
+ Position.insert(Inst);
+ }
+ };
+
+ /// \brief Set the operand of an instruction with a new value.
+ class OperandSetter : public TypePromotionAction {
+ /// Original operand of the instruction.
+ Value *Origin;
+ /// Index of the modified instruction.
+ unsigned Idx;
+
+ public:
+ /// \brief Set \p Idx operand of \p Inst with \p NewVal.
+ OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
+ : TypePromotionAction(Inst), Idx(Idx) {
+ DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"
+ << "for:" << *Inst << "\n"
+ << "with:" << *NewVal << "\n");
+ Origin = Inst->getOperand(Idx);
+ Inst->setOperand(Idx, NewVal);
+ }
+
+ /// \brief Restore the original value of the instruction.
+ void undo() {
+ DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"
+ << "for: " << *Inst << "\n"
+ << "with: " << *Origin << "\n");
+ Inst->setOperand(Idx, Origin);
+ }
+ };
+
+ /// \brief Hide the operands of an instruction.
+ /// Do as if this instruction was not using any of its operands.
+ class OperandsHider : public TypePromotionAction {
+ /// The list of original operands.
+ SmallVector<Value *, 4> OriginalValues;
+
+ public:
+ /// \brief Remove \p Inst from the uses of the operands of \p Inst.
+ OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
+ DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n");
+ unsigned NumOpnds = Inst->getNumOperands();
+ OriginalValues.reserve(NumOpnds);
+ for (unsigned It = 0; It < NumOpnds; ++It) {
+ // Save the current operand.
+ Value *Val = Inst->getOperand(It);
+ OriginalValues.push_back(Val);
+ // Set a dummy one.
+ // We could use OperandSetter here, but that would implied an overhead
+ // that we are not willing to pay.
+ Inst->setOperand(It, UndefValue::get(Val->getType()));
+ }
+ }
+
+ /// \brief Restore the original list of uses.
+ void undo() {
+ DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n");
+ for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
+ Inst->setOperand(It, OriginalValues[It]);
+ }
+ };
+
+ /// \brief Build a truncate instruction.
+ class TruncBuilder : public TypePromotionAction {
+ public:
+ /// \brief Build a truncate instruction of \p Opnd producing a \p Ty
+ /// result.
+ /// trunc Opnd to Ty.
+ TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
+ IRBuilder<> Builder(Opnd);
+ Inst = cast<Instruction>(Builder.CreateTrunc(Opnd, Ty, "promoted"));
+ DEBUG(dbgs() << "Do: TruncBuilder: " << *Inst << "\n");
+ }
+
+ /// \brief Get the built instruction.
+ Instruction *getBuiltInstruction() { return Inst; }
+
+ /// \brief Remove the built instruction.
+ void undo() {
+ DEBUG(dbgs() << "Undo: TruncBuilder: " << *Inst << "\n");
+ Inst->eraseFromParent();
+ }
+ };
+
+ /// \brief Build a sign extension instruction.
+ class SExtBuilder : public TypePromotionAction {
+ public:
+ /// \brief Build a sign extension instruction of \p Opnd producing a \p Ty
+ /// result.
+ /// sext Opnd to Ty.
+ SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
+ : TypePromotionAction(Inst) {
+ IRBuilder<> Builder(InsertPt);
+ Inst = cast<Instruction>(Builder.CreateSExt(Opnd, Ty, "promoted"));
+ DEBUG(dbgs() << "Do: SExtBuilder: " << *Inst << "\n");
+ }
+
+ /// \brief Get the built instruction.
+ Instruction *getBuiltInstruction() { return Inst; }
+
+ /// \brief Remove the built instruction.
+ void undo() {
+ DEBUG(dbgs() << "Undo: SExtBuilder: " << *Inst << "\n");
+ Inst->eraseFromParent();
+ }
+ };
+
+ /// \brief Mutate an instruction to another type.
+ class TypeMutator : public TypePromotionAction {
+ /// Record the original type.
+ Type *OrigTy;
+
+ public:
+ /// \brief Mutate the type of \p Inst into \p NewTy.
+ TypeMutator(Instruction *Inst, Type *NewTy)
+ : TypePromotionAction(Inst), OrigTy(Inst->getType()) {
+ DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTy
+ << "\n");
+ Inst->mutateType(NewTy);
+ }
+
+ /// \brief Mutate the instruction back to its original type.
+ void undo() {
+ DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTy
+ << "\n");
+ Inst->mutateType(OrigTy);
+ }
+ };
+
+ /// \brief Replace the uses of an instruction by another instruction.
+ class UsesReplacer : public TypePromotionAction {
+ /// Helper structure to keep track of the replaced uses.
+ struct InstructionAndIdx {
+ /// The instruction using the instruction.
+ Instruction *Inst;
+ /// The index where this instruction is used for Inst.
+ unsigned Idx;
+ InstructionAndIdx(Instruction *Inst, unsigned Idx)
+ : Inst(Inst), Idx(Idx) {}
+ };
+
+ /// Keep track of the original uses (pair Instruction, Index).
+ SmallVector<InstructionAndIdx, 4> OriginalUses;
+ typedef SmallVectorImpl<InstructionAndIdx>::iterator use_iterator;
+
+ public:
+ /// \brief Replace all the use of \p Inst by \p New.
+ UsesReplacer(Instruction *Inst, Value *New) : TypePromotionAction(Inst) {
+ DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *New
+ << "\n");
+ // Record the original uses.
+ for (Value::use_iterator UseIt = Inst->use_begin(),
+ EndIt = Inst->use_end();
+ UseIt != EndIt; ++UseIt) {
+ Instruction *Use = cast<Instruction>(*UseIt);
+ OriginalUses.push_back(InstructionAndIdx(Use, UseIt.getOperandNo()));
+ }
+ // Now, we can replace the uses.
+ Inst->replaceAllUsesWith(New);
+ }
+
+ /// \brief Reassign the original uses of Inst to Inst.
+ void undo() {
+ DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n");
+ for (use_iterator UseIt = OriginalUses.begin(),
+ EndIt = OriginalUses.end();
+ UseIt != EndIt; ++UseIt) {
+ UseIt->Inst->setOperand(UseIt->Idx, Inst);
+ }
+ }
+ };
+
+ /// \brief Remove an instruction from the IR.
+ class InstructionRemover : public TypePromotionAction {
+ /// Original position of the instruction.
+ InsertionHandler Inserter;
+ /// Helper structure to hide all the link to the instruction. In other
+ /// words, this helps to do as if the instruction was removed.
+ OperandsHider Hider;
+ /// Keep track of the uses replaced, if any.
+ UsesReplacer *Replacer;
+
+ public:
+ /// \brief Remove all reference of \p Inst and optinally replace all its
+ /// uses with New.
+ /// \pre If !Inst->use_empty(), then New != NULL
+ InstructionRemover(Instruction *Inst, Value *New = NULL)
+ : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
+ Replacer(NULL) {
+ if (New)
+ Replacer = new UsesReplacer(Inst, New);
+ DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n");
+ Inst->removeFromParent();
+ }
+
+ ~InstructionRemover() { delete Replacer; }
+
+ /// \brief Really remove the instruction.
+ void commit() { delete Inst; }
+
+ /// \brief Resurrect the instruction and reassign it to the proper uses if
+ /// new value was provided when build this action.
+ void undo() {
+ DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n");
+ Inserter.insert(Inst);
+ if (Replacer)
+ Replacer->undo();
+ Hider.undo();
+ }
+ };
+
+public:
+ /// Restoration point.
+ /// The restoration point is a pointer to an action instead of an iterator
+ /// because the iterator may be invalidated but not the pointer.
+ typedef const TypePromotionAction *ConstRestorationPt;
+ /// Advocate every changes made in that transaction.
+ void commit();
+ /// Undo all the changes made after the given point.
+ void rollback(ConstRestorationPt Point);
+ /// Get the current restoration point.
+ ConstRestorationPt getRestorationPoint() const;
+
+ /// \name API for IR modification with state keeping to support rollback.
+ /// @{
+ /// Same as Instruction::setOperand.
+ void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);
+ /// Same as Instruction::eraseFromParent.
+ void eraseInstruction(Instruction *Inst, Value *NewVal = NULL);
+ /// Same as Value::replaceAllUsesWith.
+ void replaceAllUsesWith(Instruction *Inst, Value *New);
+ /// Same as Value::mutateType.
+ void mutateType(Instruction *Inst, Type *NewTy);
+ /// Same as IRBuilder::createTrunc.
+ Instruction *createTrunc(Instruction *Opnd, Type *Ty);
+ /// Same as IRBuilder::createSExt.
+ Instruction *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);
+ /// Same as Instruction::moveBefore.
+ void moveBefore(Instruction *Inst, Instruction *Before);
+ /// @}
+
+ ~TypePromotionTransaction();
+
+private:
+ /// The ordered list of actions made so far.
+ SmallVector<TypePromotionAction *, 16> Actions;
+ typedef SmallVectorImpl<TypePromotionAction *>::iterator CommitPt;
+};
+
+void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
+ Value *NewVal) {
+ Actions.push_back(
+ new TypePromotionTransaction::OperandSetter(Inst, Idx, NewVal));
+}
+
+void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
+ Value *NewVal) {
+ Actions.push_back(
+ new TypePromotionTransaction::InstructionRemover(Inst, NewVal));
+}
+
+void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
+ Value *New) {
+ Actions.push_back(new TypePromotionTransaction::UsesReplacer(Inst, New));
+}
+
+void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
+ Actions.push_back(new TypePromotionTransaction::TypeMutator(Inst, NewTy));
+}
+
+Instruction *TypePromotionTransaction::createTrunc(Instruction *Opnd,
+ Type *Ty) {
+ TruncBuilder *TB = new TruncBuilder(Opnd, Ty);
+ Actions.push_back(TB);
+ return TB->getBuiltInstruction();
+}
+
+Instruction *TypePromotionTransaction::createSExt(Instruction *Inst,
+ Value *Opnd, Type *Ty) {
+ SExtBuilder *SB = new SExtBuilder(Inst, Opnd, Ty);
+ Actions.push_back(SB);
+ return SB->getBuiltInstruction();
+}
+
+void TypePromotionTransaction::moveBefore(Instruction *Inst,
+ Instruction *Before) {
+ Actions.push_back(
+ new TypePromotionTransaction::InstructionMoveBefore(Inst, Before));
+}
+
+TypePromotionTransaction::ConstRestorationPt
+TypePromotionTransaction::getRestorationPoint() const {
+ return Actions.rbegin() != Actions.rend() ? *Actions.rbegin() : NULL;
+}
+
+void TypePromotionTransaction::commit() {
+ for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt;
+ ++It) {
+ (*It)->commit();
+ delete *It;
+ }
+ Actions.clear();
+}
+
+void TypePromotionTransaction::rollback(
+ TypePromotionTransaction::ConstRestorationPt Point) {
+ while (!Actions.empty() && Point != (*Actions.rbegin())) {
+ TypePromotionAction *Curr = Actions.pop_back_val();
+ Curr->undo();
+ delete Curr;
+ }
+}
+
+TypePromotionTransaction::~TypePromotionTransaction() {
+ for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt; ++It)
+ delete *It;
+ Actions.clear();
+}
+
+/// \brief A helper class for matching addressing modes.
+///
+/// This encapsulates the logic for matching the target-legal addressing modes.
+class AddressingModeMatcher {
+ SmallVectorImpl<Instruction*> &AddrModeInsts;
+ const TargetLowering &TLI;
+
+ /// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
+ /// the memory instruction that we're computing this address for.
+ Type *AccessTy;
+ Instruction *MemoryInst;
+
+ /// AddrMode - This is the addressing mode that we're building up. This is
+ /// part of the return value of this addressing mode matching stuff.
+ ExtAddrMode &AddrMode;
+
+ /// The truncate instruction inserted by other CodeGenPrepare optimizations.
+ const SetOfInstrs &InsertedTruncs;
+ /// A map from the instructions to their type before promotion.
+ InstrToOrigTy &PromotedInsts;
+ /// The ongoing transaction where every action should be registered.
+ TypePromotionTransaction &TPT;
+
+ /// IgnoreProfitability - This is set to true when we should not do
+ /// profitability checks. When true, IsProfitableToFoldIntoAddressingMode
+ /// always returns true.
+ bool IgnoreProfitability;
+
+ AddressingModeMatcher(SmallVectorImpl<Instruction*> &AMI,
+ const TargetLowering &T, Type *AT,
+ Instruction *MI, ExtAddrMode &AM,
+ const SetOfInstrs &InsertedTruncs,
+ InstrToOrigTy &PromotedInsts,
+ TypePromotionTransaction &TPT)
+ : AddrModeInsts(AMI), TLI(T), AccessTy(AT), MemoryInst(MI), AddrMode(AM),
+ InsertedTruncs(InsertedTruncs), PromotedInsts(PromotedInsts), TPT(TPT) {
+ IgnoreProfitability = false;
+ }
+public:
+
+ /// Match - Find the maximal addressing mode that a load/store of V can fold,
+ /// give an access type of AccessTy. This returns a list of involved
+ /// instructions in AddrModeInsts.
+ /// \p InsertedTruncs The truncate instruction inserted by other
+ /// CodeGenPrepare
+ /// optimizations.
+ /// \p PromotedInsts maps the instructions to their type before promotion.
+ /// \p The ongoing transaction where every action should be registered.
+ static ExtAddrMode Match(Value *V, Type *AccessTy,
+ Instruction *MemoryInst,
+ SmallVectorImpl<Instruction*> &AddrModeInsts,
+ const TargetLowering &TLI,
+ const SetOfInstrs &InsertedTruncs,
+ InstrToOrigTy &PromotedInsts,
+ TypePromotionTransaction &TPT) {
+ ExtAddrMode Result;
+
+ bool Success = AddressingModeMatcher(AddrModeInsts, TLI, AccessTy,
+ MemoryInst, Result, InsertedTruncs,
+ PromotedInsts, TPT).MatchAddr(V, 0);
+ (void)Success; assert(Success && "Couldn't select *anything*?");
+ return Result;
+ }
+private:
+ bool MatchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
+ bool MatchAddr(Value *V, unsigned Depth);
+ bool MatchOperationAddr(User *Operation, unsigned Opcode, unsigned Depth,
+ bool *MovedAway = NULL);
+ bool IsProfitableToFoldIntoAddressingMode(Instruction *I,
+ ExtAddrMode &AMBefore,
+ ExtAddrMode &AMAfter);
+ bool ValueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
+ bool IsPromotionProfitable(unsigned MatchedSize, unsigned SizeWithPromotion,
+ Value *PromotedOperand) const;
+};
+
+/// MatchScaledValue - Try adding ScaleReg*Scale to the current addressing mode.
+/// Return true and update AddrMode if this addr mode is legal for the target,
+/// false if not.
+bool AddressingModeMatcher::MatchScaledValue(Value *ScaleReg, int64_t Scale,
+ unsigned Depth) {
+ // If Scale is 1, then this is the same as adding ScaleReg to the addressing
+ // mode. Just process that directly.
+ if (Scale == 1)
+ return MatchAddr(ScaleReg, Depth);
+
+ // If the scale is 0, it takes nothing to add this.
+ if (Scale == 0)
+ return true;
+
+ // If we already have a scale of this value, we can add to it, otherwise, we
+ // need an available scale field.
+ if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
+ return false;
+
+ ExtAddrMode TestAddrMode = AddrMode;
+
+ // Add scale to turn X*4+X*3 -> X*7. This could also do things like
+ // [A+B + A*7] -> [B+A*8].
+ TestAddrMode.Scale += Scale;
+ TestAddrMode.ScaledReg = ScaleReg;
+
+ // If the new address isn't legal, bail out.
+ if (!TLI.isLegalAddressingMode(TestAddrMode, AccessTy))
+ return false;
+
+ // It was legal, so commit it.
+ AddrMode = TestAddrMode;
+
+ // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
+ // to see if ScaleReg is actually X+C. If so, we can turn this into adding
+ // X*Scale + C*Scale to addr mode.
+ ConstantInt *CI = 0; Value *AddLHS = 0;
+ if (isa<Instruction>(ScaleReg) && // not a constant expr.
+ match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI)))) {
+ TestAddrMode.ScaledReg = AddLHS;
+ TestAddrMode.BaseOffs += CI->getSExtValue()*TestAddrMode.Scale;
+
+ // If this addressing mode is legal, commit it and remember that we folded
+ // this instruction.
+ if (TLI.isLegalAddressingMode(TestAddrMode, AccessTy)) {
+ AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
+ AddrMode = TestAddrMode;
+ return true;
+ }
+ }
+
+ // Otherwise, not (x+c)*scale, just return what we have.
+ return true;
+}
+
+/// MightBeFoldableInst - This is a little filter, which returns true if an
+/// addressing computation involving I might be folded into a load/store
+/// accessing it. This doesn't need to be perfect, but needs to accept at least
+/// the set of instructions that MatchOperationAddr can.
+static bool MightBeFoldableInst(Instruction *I) {
+ switch (I->getOpcode()) {
+ case Instruction::BitCast:
+ // Don't touch identity bitcasts.
+ if (I->getType() == I->getOperand(0)->getType())
+ return false;
+ return I->getType()->isPointerTy() || I->getType()->isIntegerTy();
+ case Instruction::PtrToInt:
+ // PtrToInt is always a noop, as we know that the int type is pointer sized.
+ return true;
+ case Instruction::IntToPtr:
+ // We know the input is intptr_t, so this is foldable.
+ return true;
+ case Instruction::Add:
+ return true;
+ case Instruction::Mul:
+ case Instruction::Shl:
+ // Can only handle X*C and X << C.
+ return isa<ConstantInt>(I->getOperand(1));
+ case Instruction::GetElementPtr:
+ return true;
+ default:
+ return false;
+ }
+}
+
+/// \brief Hepler class to perform type promotion.
+class TypePromotionHelper {
+ /// \brief Utility function to check whether or not a sign extension of
+ /// \p Inst with \p ConsideredSExtType can be moved through \p Inst by either
+ /// using the operands of \p Inst or promoting \p Inst.
+ /// In other words, check if:
+ /// sext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredSExtType.
+ /// #1 Promotion applies:
+ /// ConsideredSExtType Inst (sext opnd1 to ConsideredSExtType, ...).
+ /// #2 Operand reuses:
+ /// sext opnd1 to ConsideredSExtType.
+ /// \p PromotedInsts maps the instructions to their type before promotion.
+ static bool canGetThrough(const Instruction *Inst, Type *ConsideredSExtType,
+ const InstrToOrigTy &PromotedInsts);
+
+ /// \brief Utility function to determine if \p OpIdx should be promoted when
+ /// promoting \p Inst.
+ static bool shouldSExtOperand(const Instruction *Inst, int OpIdx) {
+ if (isa<SelectInst>(Inst) && OpIdx == 0)
+ return false;
+ return true;
+ }
+
+ /// \brief Utility function to promote the operand of \p SExt when this
+ /// operand is a promotable 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 SExt.
+ /// Should never be called directly.
+ /// \return The promoted value which is used instead of SExt.
+ static Value *promoteOperandForTruncAndSExt(Instruction *SExt,
+ TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts,
+ unsigned &CreatedInsts);
+
+ /// \brief Utility function to promote the operand of \p SExt 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 SExt.
+ /// Should never be called directly.
+ /// \return The promoted value which is used instead of SExt.
+ static Value *promoteOperandForOther(Instruction *SExt,
+ TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts,
+ unsigned &CreatedInsts);
+
+public:
+ /// Type for the utility function that promotes the operand of SExt.
+ typedef Value *(*Action)(Instruction *SExt, TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts,
+ unsigned &CreatedInsts);
+ /// \brief Given a sign extend instruction \p SExt, return the approriate
+ /// action to promote the operand of \p SExt instead of using SExt.
+ /// \return NULL if no promotable action is possible with the current
+ /// sign extension.
+ /// \p InsertedTruncs keeps track of all the truncate instructions inserted by
+ /// the others CodeGenPrepare optimizations. This information is important
+ /// because we do not want to promote these instructions as CodeGenPrepare
+ /// will reinsert them later. Thus creating an infinite loop: create/remove.
+ /// \p PromotedInsts maps the instructions to their type before promotion.
+ static Action getAction(Instruction *SExt, const SetOfInstrs &InsertedTruncs,
+ const TargetLowering &TLI,
+ const InstrToOrigTy &PromotedInsts);
+};
+
+bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
+ Type *ConsideredSExtType,
+ const InstrToOrigTy &PromotedInsts) {
+ // We can always get through sext.
+ if (isa<SExtInst>(Inst))
+ return true;
+
+ // We can get through binary operator, if it is legal. In other words, the
+ // binary operator must have a nuw or nsw flag.
+ const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst);
+ if (BinOp && isa<OverflowingBinaryOperator>(BinOp) &&
+ (BinOp->hasNoUnsignedWrap() || BinOp->hasNoSignedWrap()))
+ return true;
+
+ // Check if we can do the following simplification.
+ // sext(trunc(sext)) --> sext
+ if (!isa<TruncInst>(Inst))
+ return false;
+
+ Value *OpndVal = Inst->getOperand(0);
+ // Check if we can use this operand in the sext.
+ // If the type is larger than the result type of the sign extension,
+ // we cannot.
+ if (OpndVal->getType()->getIntegerBitWidth() >
+ ConsideredSExtType->getIntegerBitWidth())
+ return false;
+
+ // If the operand of the truncate is not an instruction, we will not have
+ // any information on the dropped bits.
+ // (Actually we could for constant but it is not worth the extra logic).
+ Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
+ if (!Opnd)
+ return false;
+
+ // Check if the source of the type is narrow enough.
+ // I.e., check that trunc just drops sign extended bits.
+ // #1 get the type of the operand.
+ const Type *OpndType;
+ InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
+ if (It != PromotedInsts.end())
+ OpndType = It->second;
+ else if (isa<SExtInst>(Opnd))
+ OpndType = cast<Instruction>(Opnd)->getOperand(0)->getType();
+ else
+ return false;
+
+ // #2 check that the truncate just drop sign extended bits.
+ if (Inst->getType()->getIntegerBitWidth() >= OpndType->getIntegerBitWidth())
+ return true;
+
+ return false;
+}
+
+TypePromotionHelper::Action TypePromotionHelper::getAction(
+ Instruction *SExt, const SetOfInstrs &InsertedTruncs,
+ const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
+ Instruction *SExtOpnd = dyn_cast<Instruction>(SExt->getOperand(0));
+ Type *SExtTy = SExt->getType();
+ // If the operand of the sign extension is not an instruction, we cannot
+ // get through.
+ // If it, check we can get through.
+ if (!SExtOpnd || !canGetThrough(SExtOpnd, SExtTy, PromotedInsts))
+ return NULL;
+
+ // Do not promote if the operand has been added by codegenprepare.
+ // Otherwise, it means we are undoing an optimization that is likely to be
+ // redone, thus causing potential infinite loop.
+ if (isa<TruncInst>(SExtOpnd) && InsertedTruncs.count(SExtOpnd))
+ return NULL;
+
+ // SExt or Trunc instructions.
+ // Return the related handler.
+ if (isa<SExtInst>(SExtOpnd) || isa<TruncInst>(SExtOpnd))
+ return promoteOperandForTruncAndSExt;
+
+ // Regular instruction.
+ // Abort early if we will have to insert non-free instructions.
+ if (!SExtOpnd->hasOneUse() &&
+ !TLI.isTruncateFree(SExtTy, SExtOpnd->getType()))
+ return NULL;
+ return promoteOperandForOther;
+}
+
+Value *TypePromotionHelper::promoteOperandForTruncAndSExt(
+ llvm::Instruction *SExt, TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts) {
+ // 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));
+ // Replace sext(trunc(opnd)) or sext(sext(opnd))
+ // => sext(opnd).
+ TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
+ CreatedInsts = 0;
+
+ // Remove dead code.
+ if (SExtOpnd->use_empty())
+ TPT.eraseInstruction(SExtOpnd);
+
+ // Check if the sext is still needed.
+ if (SExt->getType() != SExt->getOperand(0)->getType())
+ return SExt;
+
+ // At this point we have: sext ty opnd to ty.
+ // Reassign the uses of SExt to the opnd and remove SExt.
+ Value *NextVal = SExt->getOperand(0);
+ TPT.eraseInstruction(SExt, NextVal);
+ return NextVal;
+}
+
+Value *
+TypePromotionHelper::promoteOperandForOther(Instruction *SExt,
+ TypePromotionTransaction &TPT,
+ InstrToOrigTy &PromotedInsts,
+ unsigned &CreatedInsts) {
+ // 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));
+ CreatedInsts = 0;
+ if (!SExtOpnd->hasOneUse()) {
+ // SExtOpnd will be promoted.
+ // All its uses, but SExt, will need to use a truncated value of the
+ // promoted version.
+ // Create the truncate now.
+ Instruction *Trunc = TPT.createTrunc(SExt, SExtOpnd->getType());
+ Trunc->removeFromParent();
+ // Insert it just after the definition.
+ Trunc->insertAfter(SExtOpnd);
+
+ TPT.replaceAllUsesWith(SExtOpnd, Trunc);
+ // Restore the operand of SExt (which has been replace by the previous call
+ // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
+ TPT.setOperand(SExt, 0, SExtOpnd);
+ }
+
+ // Get through the Instruction:
+ // 1. Update its type.
+ // 2. Replace the uses of SExt by Inst.
+ // 3. Sign extend each operand that needs to be sign extended.
+
+ // Remember the original type of the instruction before promotion.
+ // This is useful to know that the high bits are sign extended bits.
+ PromotedInsts.insert(
+ std::pair<Instruction *, Type *>(SExtOpnd, SExtOpnd->getType()));
+ // Step #1.
+ TPT.mutateType(SExtOpnd, SExt->getType());
+ // Step #2.
+ TPT.replaceAllUsesWith(SExt, SExtOpnd);
+ // Step #3.
+ Instruction *SExtForOpnd = SExt;
+
+ DEBUG(dbgs() << "Propagate SExt to operands\n");
+ for (int OpIdx = 0, EndOpIdx = SExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
+ ++OpIdx) {
+ DEBUG(dbgs() << "Operand:\n" << *(SExtOpnd->getOperand(OpIdx)) << '\n');
+ if (SExtOpnd->getOperand(OpIdx)->getType() == SExt->getType() ||
+ !shouldSExtOperand(SExtOpnd, OpIdx)) {
+ DEBUG(dbgs() << "No need to propagate\n");
+ continue;
+ }
+ // Check if we can statically sign extend the operand.
+ Value *Opnd = SExtOpnd->getOperand(OpIdx);
+ if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
+ DEBUG(dbgs() << "Statically sign extend\n");
+ TPT.setOperand(
+ SExtOpnd, OpIdx,
+ ConstantInt::getSigned(SExt->getType(), Cst->getSExtValue()));
+ continue;
+ }
+ // UndefValue are typed, so we have to statically sign extend them.
+ if (isa<UndefValue>(Opnd)) {
+ DEBUG(dbgs() << "Statically sign extend\n");
+ TPT.setOperand(SExtOpnd, OpIdx, UndefValue::get(SExt->getType()));
+ continue;
+ }
+
+ // Otherwise we have to explicity sign extend the operand.
+ // Check if SExt was reused to sign extend an operand.
+ if (!SExtForOpnd) {
+ // If yes, create a new one.
+ DEBUG(dbgs() << "More operands to sext\n");
+ SExtForOpnd = TPT.createSExt(SExt, Opnd, SExt->getType());
+ ++CreatedInsts;
+ }
+
+ TPT.setOperand(SExtForOpnd, 0, Opnd);
+
+ // Move the sign extension before the insertion point.
+ TPT.moveBefore(SExtForOpnd, SExtOpnd);
+ TPT.setOperand(SExtOpnd, OpIdx, SExtForOpnd);
+ // If more sext are required, new instructions will have to be created.
+ SExtForOpnd = NULL;
+ }
+ if (SExtForOpnd == SExt) {
+ DEBUG(dbgs() << "Sign extension is useless now\n");
+ TPT.eraseInstruction(SExt);
+ }
+ return SExtOpnd;
+}
+
+/// IsPromotionProfitable - Check whether or not promoting an instruction
+/// to a wider type was profitable.
+/// \p MatchedSize gives the number of instructions that have been matched
+/// in the addressing mode after the promotion was applied.
+/// \p SizeWithPromotion gives the number of created instructions for
+/// the promotion plus the number of instructions that have been
+/// matched in the addressing mode before the promotion.
+/// \p PromotedOperand is the value that has been promoted.
+/// \return True if the promotion is profitable, false otherwise.
+bool
+AddressingModeMatcher::IsPromotionProfitable(unsigned MatchedSize,
+ unsigned SizeWithPromotion,
+ Value *PromotedOperand) const {
+ // We folded less instructions than what we created to promote the operand.
+ // This is not profitable.
+ if (MatchedSize < SizeWithPromotion)
+ return false;
+ if (MatchedSize > SizeWithPromotion)
+ return true;
+ // 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;
+ return TLI.isOperationLegalOrCustom(PromotedInst->getOpcode(),
+ EVT::getEVT(PromotedInst->getType()));
+}
+
+/// MatchOperationAddr - Given an instruction or constant expr, see if we can
+/// fold the operation into the addressing mode. If so, update the addressing
+/// mode and return true, otherwise return false without modifying AddrMode.
+/// If \p MovedAway is not NULL, it contains the information of whether or
+/// not AddrInst has to be folded into the addressing mode on success.
+/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
+/// because it has been moved away.
+/// Thus AddrInst must not be added in the matched instructions.
+/// This state can happen when AddrInst is a sext, since it may be moved away.
+/// Therefore, AddrInst may not be valid when MovedAway is true and it must
+/// not be referenced anymore.
+bool AddressingModeMatcher::MatchOperationAddr(User *AddrInst, unsigned Opcode,
+ unsigned Depth,
+ bool *MovedAway) {
+ // Avoid exponential behavior on extremely deep expression trees.
+ if (Depth >= 5) return false;
+
+ // By default, all matched instructions stay in place.
+ if (MovedAway)
+ *MovedAway = false;
+
+ switch (Opcode) {
+ case Instruction::PtrToInt:
+ // PtrToInt is always a noop, as we know that the int type is pointer sized.
+ return MatchAddr(AddrInst->getOperand(0), Depth);
+ case Instruction::IntToPtr:
+ // This inttoptr is a no-op if the integer type is pointer sized.
+ if (TLI.getValueType(AddrInst->getOperand(0)->getType()) ==
+ TLI.getPointerTy(AddrInst->getType()->getPointerAddressSpace()))
+ return MatchAddr(AddrInst->getOperand(0), Depth);
+ return false;
+ case Instruction::BitCast:
+ // BitCast is always a noop, and we can handle it as long as it is
+ // int->int or pointer->pointer (we don't want int<->fp or something).
+ if ((AddrInst->getOperand(0)->getType()->isPointerTy() ||
+ AddrInst->getOperand(0)->getType()->isIntegerTy()) &&
+ // Don't touch identity bitcasts. These were probably put here by LSR,
+ // and we don't want to mess around with them. Assume it knows what it
+ // is doing.
+ AddrInst->getOperand(0)->getType() != AddrInst->getType())
+ return MatchAddr(AddrInst->getOperand(0), Depth);
+ return false;
+ case Instruction::Add: {
+ // Check to see if we can merge in the RHS then the LHS. If so, we win.
+ ExtAddrMode BackupAddrMode = AddrMode;
+ unsigned OldSize = AddrModeInsts.size();
+ // Start a transaction at this point.
+ // The LHS may match but not the RHS.
+ // Therefore, we need a higher level restoration point to undo partially
+ // matched operation.
+ TypePromotionTransaction::ConstRestorationPt LastKnownGood =
+ TPT.getRestorationPoint();
+
+ if (MatchAddr(AddrInst->getOperand(1), Depth+1) &&
+ MatchAddr(AddrInst->getOperand(0), Depth+1))
+ return true;
+
+ // Restore the old addr mode info.
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ TPT.rollback(LastKnownGood);
+
+ // Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
+ if (MatchAddr(AddrInst->getOperand(0), Depth+1) &&
+ MatchAddr(AddrInst->getOperand(1), Depth+1))
+ return true;
+
+ // Otherwise we definitely can't merge the ADD in.
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ TPT.rollback(LastKnownGood);
+ break;
+ }
+ //case Instruction::Or:
+ // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
+ //break;
+ case Instruction::Mul:
+ case Instruction::Shl: {
+ // Can only handle X*C and X << C.
+ ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
+ if (!RHS) return false;
+ int64_t Scale = RHS->getSExtValue();
+ if (Opcode == Instruction::Shl)
+ Scale = 1LL << Scale;
+
+ return MatchScaledValue(AddrInst->getOperand(0), Scale, Depth);
+ }
+ case Instruction::GetElementPtr: {
+ // Scan the GEP. We check it if it contains constant offsets and at most
+ // one variable offset.
+ int VariableOperand = -1;
+ unsigned VariableScale = 0;
+
+ int64_t ConstantOffset = 0;
+ const DataLayout *TD = TLI.getDataLayout();
+ gep_type_iterator GTI = gep_type_begin(AddrInst);
+ for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
+ if (StructType *STy = dyn_cast<StructType>(*GTI)) {
+ const StructLayout *SL = TD->getStructLayout(STy);
+ unsigned Idx =
+ cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
+ ConstantOffset += SL->getElementOffset(Idx);
+ } else {
+ uint64_t TypeSize = TD->getTypeAllocSize(GTI.getIndexedType());
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
+ ConstantOffset += CI->getSExtValue()*TypeSize;
+ } else if (TypeSize) { // Scales of zero don't do anything.
+ // We only allow one variable index at the moment.
+ if (VariableOperand != -1)
+ return false;
+
+ // Remember the variable index.
+ VariableOperand = i;
+ VariableScale = TypeSize;
+ }
+ }
+ }
+
+ // A common case is for the GEP to only do a constant offset. In this case,
+ // just add it to the disp field and check validity.
+ if (VariableOperand == -1) {
+ AddrMode.BaseOffs += ConstantOffset;
+ if (ConstantOffset == 0 || TLI.isLegalAddressingMode(AddrMode, AccessTy)){
+ // Check to see if we can fold the base pointer in too.
+ if (MatchAddr(AddrInst->getOperand(0), Depth+1))
+ return true;
+ }
+ AddrMode.BaseOffs -= ConstantOffset;
+ return false;
+ }
+
+ // Save the valid addressing mode in case we can't match.
+ ExtAddrMode BackupAddrMode = AddrMode;
+ unsigned OldSize = AddrModeInsts.size();
+
+ // See if the scale and offset amount is valid for this target.
+ AddrMode.BaseOffs += ConstantOffset;
+
+ // Match the base operand of the GEP.
+ if (!MatchAddr(AddrInst->getOperand(0), Depth+1)) {
+ // If it couldn't be matched, just stuff the value in a register.
+ if (AddrMode.HasBaseReg) {
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ return false;
+ }
+ AddrMode.HasBaseReg = true;
+ AddrMode.BaseReg = AddrInst->getOperand(0);
+ }
+
+ // Match the remaining variable portion of the GEP.
+ if (!MatchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
+ Depth)) {
+ // If it couldn't be matched, try stuffing the base into a register
+ // instead of matching it, and retrying the match of the scale.
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ if (AddrMode.HasBaseReg)
+ return false;
+ AddrMode.HasBaseReg = true;
+ AddrMode.BaseReg = AddrInst->getOperand(0);
+ AddrMode.BaseOffs += ConstantOffset;
+ if (!MatchScaledValue(AddrInst->getOperand(VariableOperand),
+ VariableScale, Depth)) {
+ // If even that didn't work, bail.
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ return false;
+ }
+ }
+
+ return true;
+ }
+ case Instruction::SExt: {
+ // Try to move this sext out of the way of the addressing mode.
+ Instruction *SExt = cast<Instruction>(AddrInst);
+ // Ask for a method for doing so.
+ TypePromotionHelper::Action TPH = TypePromotionHelper::getAction(
+ SExt, InsertedTruncs, TLI, PromotedInsts);
+ if (!TPH)
+ return false;
+
+ TypePromotionTransaction::ConstRestorationPt LastKnownGood =
+ TPT.getRestorationPoint();
+ unsigned CreatedInsts = 0;
+ Value *PromotedOperand = TPH(SExt, TPT, PromotedInsts, CreatedInsts);
+ // 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.
+ // E.g.,
+ // op = add opnd, 1
+ // idx = sext op
+ // addr = gep base, idx
+ // is now:
+ // promotedOpnd = sext opnd <- no match here
+ // op = promoted_add promotedOpnd, 1 <- match (later in recursive calls)
+ // addr = gep base, op <- match
+ if (MovedAway)
+ *MovedAway = true;
+
+ assert(PromotedOperand &&
+ "TypePromotionHelper should have filtered out those cases");
+
+ ExtAddrMode BackupAddrMode = AddrMode;
+ unsigned OldSize = AddrModeInsts.size();
+
+ if (!MatchAddr(PromotedOperand, Depth) ||
+ !IsPromotionProfitable(AddrModeInsts.size(), OldSize + CreatedInsts,
+ PromotedOperand)) {
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ DEBUG(dbgs() << "Sign extension does not pay off: rollback\n");
+ TPT.rollback(LastKnownGood);
+ return false;
+ }
+ return true;
+ }
+ }
+ return false;
+}
+
+/// MatchAddr - If we can, try to add the value of 'Addr' into the current
+/// addressing mode. If Addr can't be added to AddrMode this returns false and
+/// leaves AddrMode unmodified. This assumes that Addr is either a pointer type
+/// or intptr_t for the target.
+///
+bool AddressingModeMatcher::MatchAddr(Value *Addr, unsigned Depth) {
+ // Start a transaction at this point that we will rollback if the matching
+ // fails.
+ TypePromotionTransaction::ConstRestorationPt LastKnownGood =
+ TPT.getRestorationPoint();
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
+ // Fold in immediates if legal for the target.
+ AddrMode.BaseOffs += CI->getSExtValue();
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
+ return true;
+ AddrMode.BaseOffs -= CI->getSExtValue();
+ } else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
+ // If this is a global variable, try to fold it into the addressing mode.
+ if (AddrMode.BaseGV == 0) {
+ AddrMode.BaseGV = GV;
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
+ return true;
+ AddrMode.BaseGV = 0;
+ }
+ } else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
+ ExtAddrMode BackupAddrMode = AddrMode;
+ unsigned OldSize = AddrModeInsts.size();
+
+ // Check to see if it is possible to fold this operation.
+ bool MovedAway = false;
+ if (MatchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
+ // This instruction may have been move away. If so, there is nothing
+ // to check here.
+ if (MovedAway)
+ return true;
+ // Okay, it's possible to fold this. Check to see if it is actually
+ // *profitable* to do so. We use a simple cost model to avoid increasing
+ // register pressure too much.
+ if (I->hasOneUse() ||
+ IsProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
+ AddrModeInsts.push_back(I);
+ return true;
+ }
+
+ // It isn't profitable to do this, roll back.
+ //cerr << "NOT FOLDING: " << *I;
+ AddrMode = BackupAddrMode;
+ AddrModeInsts.resize(OldSize);
+ TPT.rollback(LastKnownGood);
+ }
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
+ if (MatchOperationAddr(CE, CE->getOpcode(), Depth))
+ return true;
+ TPT.rollback(LastKnownGood);
+ } else if (isa<ConstantPointerNull>(Addr)) {
+ // Null pointer gets folded without affecting the addressing mode.
+ return true;
+ }
+
+ // Worse case, the target should support [reg] addressing modes. :)
+ if (!AddrMode.HasBaseReg) {
+ AddrMode.HasBaseReg = true;
+ AddrMode.BaseReg = Addr;
+ // Still check for legality in case the target supports [imm] but not [i+r].
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
+ return true;
+ AddrMode.HasBaseReg = false;
+ AddrMode.BaseReg = 0;
+ }
+
+ // If the base register is already taken, see if we can do [r+r].
+ if (AddrMode.Scale == 0) {
+ AddrMode.Scale = 1;
+ AddrMode.ScaledReg = Addr;
+ if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
+ return true;
+ AddrMode.Scale = 0;
+ AddrMode.ScaledReg = 0;
+ }
+ // Couldn't match.
+ TPT.rollback(LastKnownGood);
+ return false;
+}
+
+/// IsOperandAMemoryOperand - Check to see if all uses of OpVal by the specified
+/// inline asm call are due to memory operands. If so, return true, otherwise
+/// return false.
+static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
+ const TargetLowering &TLI) {
+ TargetLowering::AsmOperandInfoVector TargetConstraints = TLI.ParseConstraints(ImmutableCallSite(CI));
+ for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
+ TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
+
+ // Compute the constraint code and ConstraintType to use.
+ TLI.ComputeConstraintToUse(OpInfo, SDValue());
+
+ // If this asm operand is our Value*, and if it isn't an indirect memory
+ // operand, we can't fold it!
+ if (OpInfo.CallOperandVal == OpVal &&
+ (OpInfo.ConstraintType != TargetLowering::C_Memory ||
+ !OpInfo.isIndirect))
+ return false;
+ }
+
+ return true;
+}
+
+/// FindAllMemoryUses - Recursively walk all the uses of I until we find a
+/// memory use. If we find an obviously non-foldable instruction, return true.
+/// Add the ultimately found memory instructions to MemoryUses.
+static bool FindAllMemoryUses(Instruction *I,
+ SmallVectorImpl<std::pair<Instruction*,unsigned> > &MemoryUses,
+ SmallPtrSet<Instruction*, 16> &ConsideredInsts,
+ const TargetLowering &TLI) {
+ // If we already considered this instruction, we're done.
+ if (!ConsideredInsts.insert(I))
+ return false;
+
+ // If this is an obviously unfoldable instruction, bail out.
+ if (!MightBeFoldableInst(I))
+ return true;
+
+ // Loop over all the uses, recursively processing them.
+ for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+ UI != E; ++UI) {
+ User *U = *UI;
+
+ if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
+ MemoryUses.push_back(std::make_pair(LI, UI.getOperandNo()));
+ continue;
+ }
+
+ if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
+ unsigned opNo = UI.getOperandNo();
+ if (opNo == 0) return true; // Storing addr, not into addr.
+ MemoryUses.push_back(std::make_pair(SI, opNo));
+ continue;
+ }
+
+ if (CallInst *CI = dyn_cast<CallInst>(U)) {
+ InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue());
+ if (!IA) return true;
+
+ // If this is a memory operand, we're cool, otherwise bail out.
+ if (!IsOperandAMemoryOperand(CI, IA, I, TLI))
+ return true;
+ continue;
+ }
+
+ if (FindAllMemoryUses(cast<Instruction>(U), MemoryUses, ConsideredInsts,
+ TLI))
+ return true;
+ }
+
+ return false;
+}
+
+/// ValueAlreadyLiveAtInst - Retrn true if Val is already known to be live at
+/// the use site that we're folding it into. If so, there is no cost to
+/// include it in the addressing mode. KnownLive1 and KnownLive2 are two values
+/// that we know are live at the instruction already.
+bool AddressingModeMatcher::ValueAlreadyLiveAtInst(Value *Val,Value *KnownLive1,
+ Value *KnownLive2) {
+ // If Val is either of the known-live values, we know it is live!
+ if (Val == 0 || Val == KnownLive1 || Val == KnownLive2)
+ return true;
+
+ // All values other than instructions and arguments (e.g. constants) are live.
+ if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true;
+
+ // If Val is a constant sized alloca in the entry block, it is live, this is
+ // true because it is just a reference to the stack/frame pointer, which is
+ // live for the whole function.
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
+ if (AI->isStaticAlloca())
+ return true;
+
+ // Check to see if this value is already used in the memory instruction's
+ // block. If so, it's already live into the block at the very least, so we
+ // can reasonably fold it.
+ return Val->isUsedInBasicBlock(MemoryInst->getParent());
+}
+
+/// IsProfitableToFoldIntoAddressingMode - It is possible for the addressing
+/// mode of the machine to fold the specified instruction into a load or store
+/// that ultimately uses it. However, the specified instruction has multiple
+/// uses. Given this, it may actually increase register pressure to fold it
+/// into the load. For example, consider this code:
+///
+/// X = ...
+/// Y = X+1
+/// use(Y) -> nonload/store
+/// Z = Y+1
+/// load Z
+///
+/// In this case, Y has multiple uses, and can be folded into the load of Z
+/// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to
+/// be live at the use(Y) line. If we don't fold Y into load Z, we use one
+/// fewer register. Since Y can't be folded into "use(Y)" we don't increase the
+/// number of computations either.
+///
+/// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If
+/// X was live across 'load Z' for other reasons, we actually *would* want to
+/// fold the addressing mode in the Z case. This would make Y die earlier.
+bool AddressingModeMatcher::
+IsProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore,
+ ExtAddrMode &AMAfter) {
+ if (IgnoreProfitability) return true;
+
+ // AMBefore is the addressing mode before this instruction was folded into it,
+ // and AMAfter is the addressing mode after the instruction was folded. Get
+ // the set of registers referenced by AMAfter and subtract out those
+ // referenced by AMBefore: this is the set of values which folding in this
+ // address extends the lifetime of.
+ //
+ // Note that there are only two potential values being referenced here,
+ // BaseReg and ScaleReg (global addresses are always available, as are any
+ // folded immediates).
+ Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;
+
+ // If the BaseReg or ScaledReg was referenced by the previous addrmode, their
+ // lifetime wasn't extended by adding this instruction.
+ if (ValueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
+ BaseReg = 0;
+ if (ValueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
+ ScaledReg = 0;
+
+ // If folding this instruction (and it's subexprs) didn't extend any live
+ // ranges, we're ok with it.
+ if (BaseReg == 0 && ScaledReg == 0)
+ return true;
+
+ // If all uses of this instruction are ultimately load/store/inlineasm's,
+ // check to see if their addressing modes will include this instruction. If
+ // so, we can fold it into all uses, so it doesn't matter if it has multiple
+ // uses.
+ SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
+ SmallPtrSet<Instruction*, 16> ConsideredInsts;
+ if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI))
+ return false; // Has a non-memory, non-foldable use!
+
+ // Now that we know that all uses of this instruction are part of a chain of
+ // computation involving only operations that could theoretically be folded
+ // into a memory use, loop over each of these uses and see if they could
+ // *actually* fold the instruction.
+ SmallVector<Instruction*, 32> MatchedAddrModeInsts;
+ for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) {
+ Instruction *User = MemoryUses[i].first;
+ unsigned OpNo = MemoryUses[i].second;
+
+ // Get the access type of this use. If the use isn't a pointer, we don't
+ // know what it accesses.
+ Value *Address = User->getOperand(OpNo);
+ if (!Address->getType()->isPointerTy())
+ return false;
+ Type *AddressAccessTy = Address->getType()->getPointerElementType();
+
+ // Do a match against the root of this address, ignoring profitability. This
+ // will tell us if the addressing mode for the memory operation will
+ // *actually* cover the shared instruction.
+ ExtAddrMode Result;
+ TypePromotionTransaction::ConstRestorationPt LastKnownGood =
+ TPT.getRestorationPoint();
+ AddressingModeMatcher Matcher(MatchedAddrModeInsts, TLI, AddressAccessTy,
+ MemoryInst, Result, InsertedTruncs,
+ PromotedInsts, TPT);
+ Matcher.IgnoreProfitability = true;
+ bool Success = Matcher.MatchAddr(Address, 0);
+ (void)Success; assert(Success && "Couldn't select *anything*?");
+
+ // The match was to check the profitability, the changes made are not
+ // part of the original matcher. Therefore, they should be dropped
+ // otherwise the original matcher will not present the right state.
+ TPT.rollback(LastKnownGood);
+
+ // If the match didn't cover I, then it won't be shared by it.
+ if (std::find(MatchedAddrModeInsts.begin(), MatchedAddrModeInsts.end(),
+ I) == MatchedAddrModeInsts.end())
+ return false;
+
+ MatchedAddrModeInsts.clear();
+ }
+
+ return true;
+}
+
+} // end anonymous namespace
+
+/// IsNonLocalValue - Return true if the specified values are defined in a
+/// different basic block than BB.
+static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
+ if (Instruction *I = dyn_cast<Instruction>(V))
+ return I->getParent() != BB;
+ return false;
+}
+
+/// OptimizeMemoryInst - Load and Store Instructions often have
+/// addressing modes that can do significant amounts of computation. As such,
+/// instruction selection will try to get the load or store to do as much
+/// computation as possible for the program. The problem is that isel can only
+/// see within a single block. As such, we sink as much legal addressing mode
+/// stuff into the block as possible.
+///
+/// This method is used to optimize both load/store and inline asms with memory
+/// operands.
+bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
+ Type *AccessTy) {
+ Value *Repl = Addr;
+
+ // Try to collapse single-value PHI nodes. This is necessary to undo
+ // unprofitable PRE transformations.
+ SmallVector<Value*, 8> worklist;
+ SmallPtrSet<Value*, 16> Visited;
+ worklist.push_back(Addr);
+
+ // Use a worklist to iteratively look through PHI nodes, and ensure that
+ // the addressing mode obtained from the non-PHI roots of the graph
+ // are equivalent.
+ Value *Consensus = 0;
+ unsigned NumUsesConsensus = 0;
+ bool IsNumUsesConsensusValid = false;
+ SmallVector<Instruction*, 16> AddrModeInsts;
+ ExtAddrMode AddrMode;
+ TypePromotionTransaction TPT;
+ TypePromotionTransaction::ConstRestorationPt LastKnownGood =
+ TPT.getRestorationPoint();
+ while (!worklist.empty()) {
+ Value *V = worklist.back();
+ worklist.pop_back();
+
+ // Break use-def graph loops.
+ if (!Visited.insert(V)) {
+ Consensus = 0;
+ break;
+ }
+
+ // For a PHI node, push all of its incoming values.
+ if (PHINode *P = dyn_cast<PHINode>(V)) {
+ for (unsigned i = 0, e = P->getNumIncomingValues(); i != e; ++i)
+ worklist.push_back(P->getIncomingValue(i));
+ continue;
+ }
+
+ // For non-PHIs, determine the addressing mode being computed.
+ SmallVector<Instruction*, 16> NewAddrModeInsts;
+ ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
+ V, AccessTy, MemoryInst, NewAddrModeInsts, *TLI, InsertedTruncsSet,
+ PromotedInsts, TPT);
+
+ // This check is broken into two cases with very similar code to avoid using
+ // getNumUses() as much as possible. Some values have a lot of uses, so
+ // calling getNumUses() unconditionally caused a significant compile-time
+ // regression.
+ if (!Consensus) {
+ Consensus = V;
+ AddrMode = NewAddrMode;
+ AddrModeInsts = NewAddrModeInsts;
+ continue;
+ } else if (NewAddrMode == AddrMode) {
+ if (!IsNumUsesConsensusValid) {
+ NumUsesConsensus = Consensus->getNumUses();
+ IsNumUsesConsensusValid = true;
+ }
+
+ // Ensure that the obtained addressing mode is equivalent to that obtained
+ // for all other roots of the PHI traversal. Also, when choosing one
+ // such root as representative, select the one with the most uses in order
+ // to keep the cost modeling heuristics in AddressingModeMatcher
+ // applicable.
+ unsigned NumUses = V->getNumUses();
+ if (NumUses > NumUsesConsensus) {
+ Consensus = V;
+ NumUsesConsensus = NumUses;
+ AddrModeInsts = NewAddrModeInsts;
+ }
+ continue;
+ }
+
+ Consensus = 0;
+ break;
+ }
+
+ // If the addressing mode couldn't be determined, or if multiple different
+ // ones were determined, bail out now.
+ if (!Consensus) {
+ TPT.rollback(LastKnownGood);
+ return false;
+ }
+ TPT.commit();
+
+ // Check to see if any of the instructions supersumed by this addr mode are
+ // non-local to I's BB.
+ bool AnyNonLocal = false;
+ for (unsigned i = 0, e = AddrModeInsts.size(); i != e; ++i) {
+ if (IsNonLocalValue(AddrModeInsts[i], MemoryInst->getParent())) {
+ AnyNonLocal = true;
+ break;
+ }
+ }
+
+ // If all the instructions matched are already in this BB, don't do anything.
+ if (!AnyNonLocal) {
+ DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrMode << "\n");
+ return false;
+ }
+
+ // Insert this computation right after this user. Since our caller is
+ // scanning from the top of the BB to the bottom, reuse of the expr are
+ // guaranteed to happen later.
+ IRBuilder<> Builder(MemoryInst);
+
+ // Now that we determined the addressing expression we want to use and know
+ // that we have to sink it into this block. Check to see if we have already
+ // done this for some other load/store instr in this block. If so, reuse the
+ // computation.
+ 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->getDataLayout()->getIntPtrType(Addr->getType());
+ Value *Result = 0;
+
+ // Start with the base register. Do this first so that subsequent address
+ // matching finds it last, which will prevent it from trying to match it
+ // as the scaled value in case it happens to be a mul. That would be
+ // problematic if we've sunk a different mul for the scale, because then
+ // we'd end up sinking both muls.
+ 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, /*isSigned=*/true, "sunkaddr");
+ Result = V;
+ }
+
+ // Add the scale value.
+ if (AddrMode.Scale) {
+ Value *V = AddrMode.ScaledReg;
+ if (V->getType() == IntPtrTy) {
+ // done.
+ } 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;
+ }
+
+ // Add in the BaseGV if present.
+ if (AddrMode.BaseGV) {
+ Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
+ if (Result)
+ Result = Builder.CreateAdd(Result, V, "sunkaddr");
+ else
+ Result = V;
+ }
+
+ // Add in the Base Offset if present.
+ 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 we have no uses, recursively delete the value and all dead instructions
+ // using it.
+ if (Repl->use_empty()) {
+ // This can cause recursive deletion, which can invalidate our iterator.
+ // Use a WeakVH to hold onto it in case this happens.
+ WeakVH IterHandle(CurInstIterator);
+ BasicBlock *BB = CurInstIterator->getParent();
+
+ RecursivelyDeleteTriviallyDeadInstructions(Repl, TLInfo);
+
+ if (IterHandle != CurInstIterator) {
+ // If the iterator instruction was recursively deleted, start over at the
+ // start of the block.
+ CurInstIterator = BB->begin();
+ SunkAddrs.clear();
+ }
+ }
+ ++NumMemoryInsts;
+ return true;
+}
+
+/// OptimizeInlineAsmInst - If there are any memory operands, use
+/// OptimizeMemoryInst to sink their address computing into the block when
+/// possible / profitable.
+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];
+
+ // Compute the constraint code and ConstraintType to use.
+ 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;
+}
+
+/// 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.
+///
+bool CodeGenPrepare::MoveExtToFormExtLoad(Instruction *I) {
+ // Look for a load being extended.
+ LoadInst *LI = dyn_cast<LoadInst>(I->getOperand(0));
+ if (!LI) return false;
+
+ // If they're already in the same block, there's nothing to do.
+ if (LI->getParent() == I->getParent())
+ return false;
+
+ // If the load has other users and the truncate is not free, this probably
+ // isn't worthwhile.
+ if (!LI->hasOneUse() &&
+ TLI && (TLI->isTypeLegal(TLI->getValueType(LI->getType())) ||
+ !TLI->isTypeLegal(TLI->getValueType(I->getType()))) &&
+ !TLI->isTruncateFree(I->getType(), LI->getType()))
+ return false;
+
+ // Check whether the target supports casts folded into loads.
+ 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;
+
+ // Move the extend into the same block as the load, so that SelectionDAG
+ // can fold it.
+ I->removeFromParent();
+ I->insertAfter(LI);
+ ++NumExtsMoved;
+ return true;
+}
+
+bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
+ BasicBlock *DefBB = I->getParent();
+
+ // If the result of a {s|z}ext and its source are both live out, rewrite all
+ // other uses of the source with result of extension.
+ Value *Src = I->getOperand(0);
+ if (Src->hasOneUse())
+ return false;
+
+ // Only do this xform if truncating is free.
+ if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
+ return false;
+
+ // Only safe to perform the optimization if the source is also defined in
+ // this block.
+ 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);
+
+ // Figure out which BB this ext is used in.
+ BasicBlock *UserBB = User->getParent();
+ if (UserBB == DefBB) continue;
+ DefIsLiveOut = true;
+ break;
+ }
+ if (!DefIsLiveOut)
+ return false;
+
+ // Make sure none of the uses are PHI nodes.
+ 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;
+ // Be conservative. We don't want this xform to end up introducing
+ // reloads just before load / store instructions.
+ if (isa<PHINode>(User) || isa<LoadInst>(User) || isa<StoreInst>(User))
+ return false;
+ }
+
+ // InsertedTruncs - Only insert one trunc in each block once.
+ 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);
+
+ // Figure out which BB this ext is used in.
+ BasicBlock *UserBB = User->getParent();
+ if (UserBB == DefBB) continue;
+
+ // Both src and def are live in this block. Rewrite the use.
+ Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
+
+ if (!InsertedTrunc) {
+ BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
+ InsertedTrunc = new TruncInst(I, Src->getType(), "", InsertPt);
+ InsertedTruncsSet.insert(InsertedTrunc);
+ }
+
+ // Replace a use of the {s|z}ext source with a use of the result.
+ TheUse = InsertedTrunc;
+ ++NumExtUses;
+ MadeChange = true;
+ }
+
+ return MadeChange;
+}
+
+/// isFormingBranchFromSelectProfitable - Returns true if a SelectInst should be
+/// turned into an explicit branch.
+static bool isFormingBranchFromSelectProfitable(SelectInst *SI) {
+ // FIXME: This should use the same heuristics as IfConversion to determine
+ // whether a select is better represented as a branch. This requires that
+ // branch probability metadata is preserved for the select, which is not the
+ // case currently.
+
+ CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
+
+ // If the branch is predicted right, an out of order CPU can avoid blocking on
+ // the compare. Emit cmovs on compares with a memory operand as branches to
+ // avoid stalls on the load from memory. If the compare has more than one use
+ // there's probably another cmov or setcc around so it's not worth emitting a
+ // branch.
+ if (!Cmp)
+ return false;
+
+ Value *CmpOp0 = Cmp->getOperand(0);
+ Value *CmpOp1 = Cmp->getOperand(1);
+
+ // We check that the memory operand has one use to avoid uses of the loaded
+ // value directly after the compare, making branches unprofitable.
+ return Cmp->hasOneUse() &&
+ ((isa<LoadInst>(CmpOp0) && CmpOp0->hasOneUse()) ||
+ (isa<LoadInst>(CmpOp1) && CmpOp1->hasOneUse()));
+}
+
+
+/// If we have a SelectInst that will likely profit from branch prediction,
+/// turn it into a branch.
+bool CodeGenPrepare::OptimizeSelectInst(SelectInst *SI) {
+ bool VectorCond = !SI->getCondition()->getType()->isIntegerTy(1);
+
+ // Can we convert the 'select' to CF ?
+ if (DisableSelectToBranch || OptSize || !TLI || VectorCond)
+ return false;
+
+ TargetLowering::SelectSupportKind SelectKind;
+ if (VectorCond)
+ SelectKind = TargetLowering::VectorMaskSelect;
+ else if (SI->getType()->isVectorTy())
+ SelectKind = TargetLowering::ScalarCondVectorVal;
+ else
+ SelectKind = TargetLowering::ScalarValSelect;
+
+ // Do we have efficient codegen support for this kind of 'selects' ?
+ if (TLI->isSelectSupported(SelectKind)) {
+ // We have efficient codegen support for the select instruction.
+ // Check if it is profitable to keep this 'select'.
+ if (!TLI->isPredictableSelectExpensive() ||
+ !isFormingBranchFromSelectProfitable(SI))
+ return false;
+ }
+
+ ModifiedDT = true;
+
+ // First, we split the block containing the select into 2 blocks.
+ BasicBlock *StartBlock = SI->getParent();
+ BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(SI));
+ BasicBlock *NextBlock = StartBlock->splitBasicBlock(SplitPt, "select.end");
+
+ // Create a new block serving as the landing pad for the branch.
+ BasicBlock *SmallBlock = BasicBlock::Create(SI->getContext(), "select.mid",
+ NextBlock->getParent(), NextBlock);
+
+ // Move the unconditional branch from the block with the select in it into our
+ // landing pad block.
+ StartBlock->getTerminator()->eraseFromParent();
+ BranchInst::Create(NextBlock, SmallBlock);
+
+ // Insert the real conditional branch based on the original condition.
+ BranchInst::Create(NextBlock, SmallBlock, SI->getCondition(), SI);
+
+ // The select itself is replaced with a PHI Node.
+ PHINode *PN = PHINode::Create(SI->getType(), 2, "", NextBlock->begin());
+ PN->takeName(SI);
+ PN->addIncoming(SI->getTrueValue(), StartBlock);
+ PN->addIncoming(SI->getFalseValue(), SmallBlock);
+ SI->replaceAllUsesWith(PN);
+ SI->eraseFromParent();
+
+ // Instruct OptimizeBlock to skip to the next block.
+ CurInstIterator = StartBlock->end();
+ ++NumSelectsExpanded;
+ return true;
+}
+
+
+bool isBroadcastShuffle(ShuffleVectorInst *SVI) {
+ SmallVector<int, 16> Mask(SVI->getShuffleMask());
+ int SplatElem = -1;
+ for (unsigned i = 0; i < Mask.size(); ++i) {
+ if (SplatElem != -1 && Mask[i] != -1 && Mask[i] != SplatElem)
+ return false;
+ SplatElem = Mask[i];
+ }
+
+ return true;
+}
+
+/// Some targets have expensive vector shifts if the lanes aren't all the same
+/// (e.g. x86 only introduced "vpsllvd" and friends with AVX2). In these cases
+/// it's often worth sinking a shufflevector splat down to its use so that
+/// codegen can spot all lanes are identical.
+bool CodeGenPrepare::OptimizeShuffleVectorInst(ShuffleVectorInst *SVI) {
+ BasicBlock *DefBB = SVI->getParent();
+
+ // Only do this xform if variable vector shifts are particularly expensive.
+ if (!TLI || !TLI->isVectorShiftByScalarCheap(SVI->getType()))
+ return false;
+
+ // We only expect better codegen by sinking a shuffle if we can recognise a
+ // constant splat.
+ if (!isBroadcastShuffle(SVI))
+ return false;
+
+ // InsertedShuffles - Only insert a shuffle in each block once.
+ DenseMap<BasicBlock*, Instruction*> InsertedShuffles;
+
+ bool MadeChange = false;
+ for (Value::use_iterator UI = SVI->use_begin(), E = SVI->use_end();
+ UI != E; ++UI) {
+ Instruction *User = cast<Instruction>(*UI);
+
+ // Figure out which BB this ext is used in.
+ BasicBlock *UserBB = User->getParent();
+ if (UserBB == DefBB) continue;
+
+ // For now only apply this when the splat is used by a shift instruction.
+ if (!User->isShift()) continue;
+
+ // Everything checks out, sink the shuffle if the user's block doesn't
+ // already have a copy.
+ Instruction *&InsertedShuffle = InsertedShuffles[UserBB];
+
+ if (!InsertedShuffle) {
+ BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
+ InsertedShuffle = new ShuffleVectorInst(SVI->getOperand(0),
+ SVI->getOperand(1),
+ SVI->getOperand(2), "", InsertPt);
+ }
+
+ User->replaceUsesOfWith(SVI, InsertedShuffle);
+ MadeChange = true;
+ }
+
+ // If we removed all uses, nuke the shuffle.
+ if (SVI->use_empty()) {
+ SVI->eraseFromParent();
+ MadeChange = true;
+ }
+
+ return MadeChange;
+}
+
+bool CodeGenPrepare::OptimizeInst(Instruction *I) {
+ 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
+ // trivial PHI, go ahead and zap it here.
+ if (Value *V = SimplifyInstruction(P, TLI ? TLI->getDataLayout() : 0,
+ TLInfo, DT)) {
+ P->replaceAllUsesWith(V);
+ P->eraseFromParent();
+ ++NumPHIsElim;
+ return true;
+ }
+ return false;
+ }
+
+ if (CastInst *CI = dyn_cast<CastInst>(I)) {
+ // If the source of the cast is a constant, then this should have
+ // already been constant folded. The only reason NOT to constant fold
+ // it is if something (e.g. LSR) was careful to place the constant
+ // evaluation in a block other than then one that uses it (e.g. to hoist
+ // the address of globals out of a loop). If this is the case, we don't
+ // want to forward-subst the cast.
+ 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))
+ if (!TLI || !TLI->hasMultipleConditionRegisters())
+ 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()) {
+ /// The GEP operand must be a pointer, so must its result -> BitCast
+ 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 (SelectInst *SI = dyn_cast<SelectInst>(I))
+ return OptimizeSelectInst(SI);
+
+ if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I))
+ return OptimizeShuffleVectorInst(SVI);
+
+ 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) {
+ SunkAddrs.clear();
+ bool MadeChange = false;
+
+ CurInstIterator = BB.begin();
+ while (CurInstIterator != BB.end())
+ MadeChange |= OptimizeInst(CurInstIterator++);
+
+ MadeChange |= DupRetToEnableTailCallOpts(&BB);
+
+ return MadeChange;
+}
+
+// llvm.dbg.value is far away from the value then iSel may not be able
+// handle it properly. iSel will drop llvm.dbg.value if it can not
+// 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) {
+ 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;
+}
add_llvm_library(LLVMScalarOpts
ADCE.cpp
- CodeGenPrepare.cpp
ConstantHoisting.cpp
ConstantProp.cpp
CorrelatedValuePropagation.cpp
+++ /dev/null
-//===- CodeGenPrepare.cpp - Prepare a function for code generation --------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass munges the code in the input function to better prepare it for
-// SelectionDAG-based code generation. This works around limitations in it's
-// basic-block-at-a-time approach. It should eventually be removed.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "codegenprepare"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/ValueMap.h"
-#include "llvm/Analysis/InstructionSimplify.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/InlineAsm.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/Pass.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/ValueHandle.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetLibraryInfo.h"
-#include "llvm/Target/TargetLowering.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"
-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");
-STATISTIC(NumSelectsExpanded, "Number of selects turned into branches");
-
-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> DisableSelectToBranch(
- "disable-cgp-select2branch", cl::Hidden, cl::init(false),
- cl::desc("Disable select to branch conversion."));
-
-namespace {
-typedef SmallPtrSet<Instruction *, 16> SetOfInstrs;
-typedef DenseMap<Instruction *, Type *> InstrToOrigTy;
-
- class CodeGenPrepare : public FunctionPass {
- /// TLI - Keep a pointer of a TargetLowering to consult for determining
- /// transformation profitability.
- const TargetMachine *TM;
- const TargetLowering *TLI;
- const TargetLibraryInfo *TLInfo;
- DominatorTree *DT;
-
- /// CurInstIterator - As we scan instructions optimizing them, this is the
- /// next instruction to optimize. Xforms that can invalidate this should
- /// update it.
- BasicBlock::iterator CurInstIterator;
-
- /// Keeps track of non-local addresses that have been sunk into a block.
- /// This allows us to avoid inserting duplicate code for blocks with
- /// multiple load/stores of the same address.
- ValueMap<Value*, Value*> SunkAddrs;
-
- /// Keeps track of all truncates inserted for the current function.
- SetOfInstrs InsertedTruncsSet;
- /// Keeps track of the type of the related instruction before their
- /// promotion for the current function.
- InstrToOrigTy PromotedInsts;
-
- /// ModifiedDT - If CFG is modified in anyway, dominator tree may need to
- /// be updated.
- bool ModifiedDT;
-
- /// OptSize - True if optimizing for size.
- bool OptSize;
-
- public:
- static char ID; // Pass identification, replacement for typeid
- explicit CodeGenPrepare(const TargetMachine *TM = 0)
- : FunctionPass(ID), TM(TM), TLI(0) {
- initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
- }
- bool runOnFunction(Function &F);
-
- const char *getPassName() const { return "CodeGen Prepare"; }
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addPreserved<DominatorTreeWrapperPass>();
- AU.addRequired<TargetLibraryInfo>();
- }
-
- private:
- bool EliminateFallThrough(Function &F);
- 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 OptimizeSelectInst(SelectInst *SI);
- bool OptimizeShuffleVectorInst(ShuffleVectorInst *SI);
- bool DupRetToEnableTailCallOpts(BasicBlock *BB);
- bool PlaceDbgValues(Function &F);
- };
-}
-
-char CodeGenPrepare::ID = 0;
-static void *initializeCodeGenPreparePassOnce(PassRegistry &Registry) {
- initializeTargetLibraryInfoPass(Registry);
- PassInfo *PI = new PassInfo(
- "Optimize for code generation", "codegenprepare", &CodeGenPrepare::ID,
- PassInfo::NormalCtor_t(callDefaultCtor<CodeGenPrepare>), false, false,
- PassInfo::TargetMachineCtor_t(callTargetMachineCtor<CodeGenPrepare>));
- Registry.registerPass(*PI, true);
- return PI;
-}
-
-void llvm::initializeCodeGenPreparePass(PassRegistry &Registry) {
- CALL_ONCE_INITIALIZATION(initializeCodeGenPreparePassOnce)
-}
-
-FunctionPass *llvm::createCodeGenPreparePass(const TargetMachine *TM) {
- return new CodeGenPrepare(TM);
-}
-
-bool CodeGenPrepare::runOnFunction(Function &F) {
- bool EverMadeChange = false;
- // Clear per function information.
- InsertedTruncsSet.clear();
- PromotedInsts.clear();
-
- ModifiedDT = false;
- if (TM) TLI = TM->getTargetLowering();
- TLInfo = &getAnalysis<TargetLibraryInfo>();
- DominatorTreeWrapperPass *DTWP =
- getAnalysisIfAvailable<DominatorTreeWrapperPass>();
- DT = DTWP ? &DTWP->getDomTree() : 0;
- OptSize = F.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
- Attribute::OptimizeForSize);
-
- /// This optimization identifies DIV instructions that can be
- /// profitably bypassed and carried out with a shorter, faster divide.
- if (!OptSize && TLI && TLI->isSlowDivBypassed()) {
- const DenseMap<unsigned int, unsigned int> &BypassWidths =
- TLI->getBypassSlowDivWidths();
- for (Function::iterator I = F.begin(); I != F.end(); I++)
- EverMadeChange |= bypassSlowDivision(F, I, BypassWidths);
- }
-
- // Eliminate blocks that contain only PHI nodes and an
- // unconditional branch.
- EverMadeChange |= EliminateMostlyEmptyBlocks(F);
-
- // llvm.dbg.value is far away from the value then iSel may not be able
- // handle it properly. iSel will drop llvm.dbg.value if it can not
- // find a node corresponding to the value.
- EverMadeChange |= PlaceDbgValues(F);
-
- bool MadeChange = true;
- while (MadeChange) {
- MadeChange = false;
- for (Function::iterator I = F.begin(); I != F.end(); ) {
- 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);
- }
-
- // Delete the dead blocks and any of their dead successors.
- MadeChange |= !WorkList.empty();
- while (!WorkList.empty()) {
- BasicBlock *BB = *WorkList.begin();
- WorkList.erase(BB);
- SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
-
- DeleteDeadBlock(BB);
-
- for (SmallVectorImpl<BasicBlock*>::iterator
- II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
- if (pred_begin(*II) == pred_end(*II))
- WorkList.insert(*II);
- }
-
- // Merge pairs of basic blocks with unconditional branches, connected by
- // a single edge.
- if (EverMadeChange || MadeChange)
- MadeChange |= EliminateFallThrough(F);
-
- if (MadeChange)
- ModifiedDT = true;
- EverMadeChange |= MadeChange;
- }
-
- if (ModifiedDT && DT)
- DT->recalculate(F);
-
- return EverMadeChange;
-}
-
-/// EliminateFallThrough - Merge basic blocks which are connected
-/// by a single edge, where one of the basic blocks has a single successor
-/// pointing to the other basic block, which has a single predecessor.
-bool CodeGenPrepare::EliminateFallThrough(Function &F) {
- bool Changed = false;
- // Scan all of the blocks in the function, except for the entry block.
- for (Function::iterator I = llvm::next(F.begin()), E = F.end(); I != E; ) {
- BasicBlock *BB = I++;
- // If the destination block has a single pred, then this is a trivial
- // edge, just collapse it.
- BasicBlock *SinglePred = BB->getSinglePredecessor();
-
- // Don't merge if BB's address is taken.
- if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue;
-
- BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
- if (Term && !Term->isConditional()) {
- Changed = true;
- DEBUG(dbgs() << "To merge:\n"<< *SinglePred << "\n\n\n");
- // 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);
-
- if (isEntry && BB != &BB->getParent()->getEntryBlock())
- BB->moveBefore(&BB->getParent()->getEntryBlock());
-
- // We have erased a block. Update the iterator.
- I = BB;
- }
- }
- return Changed;
-}
-
-/// EliminateMostlyEmptyBlocks - eliminate blocks that contain only PHI nodes,
-/// debug info directives, and an unconditional branch. Passes before isel
-/// (e.g. LSR/loopsimplify) often split edges in ways that are non-optimal for
-/// isel. Start by eliminating these blocks so we can split them the way we
-/// want them.
-bool CodeGenPrepare::EliminateMostlyEmptyBlocks(Function &F) {
- bool MadeChange = false;
- // Note that this intentionally skips the entry block.
- for (Function::iterator I = llvm::next(F.begin()), E = F.end(); I != E; ) {
- BasicBlock *BB = I++;
-
- // If this block doesn't end with an uncond branch, ignore it.
- BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
- if (!BI || !BI->isUnconditional())
- continue;
-
- // If the instruction before the branch (skipping debug info) isn't a phi
- // node, then other stuff is happening here.
- 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;
- }
-
- // Do not break infinite loops.
- BasicBlock *DestBB = BI->getSuccessor(0);
- if (DestBB == BB)
- continue;
-
- if (!CanMergeBlocks(BB, DestBB))
- continue;
-
- EliminateMostlyEmptyBlock(BB);
- MadeChange = true;
- }
- return MadeChange;
-}
-
-/// CanMergeBlocks - Return true if we can merge BB into DestBB if there is a
-/// single uncond branch between them, and BB contains no other non-phi
-/// instructions.
-bool CodeGenPrepare::CanMergeBlocks(const BasicBlock *BB,
- const BasicBlock *DestBB) const {
- // We only want to eliminate blocks whose phi nodes are used by phi nodes in
- // the successor. If there are more complex condition (e.g. preheaders),
- // don't mess around with them.
- 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 is inside DestBB block and it is a PHINode then check
- // incoming value. If incoming value is not from BB then this is
- // a complex condition (e.g. preheaders) we want to avoid here.
- 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;
- }
- }
- }
- }
-
- // If BB and DestBB contain any common predecessors, then the phi nodes in BB
- // and DestBB may have conflicting incoming values for the block. If so, we
- // can't merge the block.
- const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
- if (!DestBBPN) return true; // no conflict.
-
- // Collect the preds of BB.
- SmallPtrSet<const BasicBlock*, 16> BBPreds;
- if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
- // It is faster to get preds from a PHI than with pred_iterator.
- for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
- BBPreds.insert(BBPN->getIncomingBlock(i));
- } else {
- BBPreds.insert(pred_begin(BB), pred_end(BB));
- }
-
- // Walk the preds of DestBB.
- for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
- BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
- if (BBPreds.count(Pred)) { // Common predecessor?
- BBI = DestBB->begin();
- while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
- const Value *V1 = PN->getIncomingValueForBlock(Pred);
- const Value *V2 = PN->getIncomingValueForBlock(BB);
-
- // If V2 is a phi node in BB, look up what the mapped value will be.
- if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
- if (V2PN->getParent() == BB)
- V2 = V2PN->getIncomingValueForBlock(Pred);
-
- // If there is a conflict, bail out.
- if (V1 != V2) return false;
- }
- }
- }
-
- return true;
-}
-
-
-/// EliminateMostlyEmptyBlock - Eliminate a basic block that have only phi's and
-/// an unconditional branch in it.
-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 the destination block has a single pred, then this is a trivial edge,
- // just collapse it.
- if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
- if (SinglePred != DestBB) {
- // 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);
-
- if (isEntry && BB != &BB->getParent()->getEntryBlock())
- BB->moveBefore(&BB->getParent()->getEntryBlock());
-
- DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
- return;
- }
- }
-
- // Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
- // to handle the new incoming edges it is about to have.
- PHINode *PN;
- for (BasicBlock::iterator BBI = DestBB->begin();
- (PN = dyn_cast<PHINode>(BBI)); ++BBI) {
- // Remove the incoming value for BB, and remember it.
- Value *InVal = PN->removeIncomingValue(BB, false);
-
- // Two options: either the InVal is a phi node defined in BB or it is some
- // value that dominates BB.
- PHINode *InValPhi = dyn_cast<PHINode>(InVal);
- if (InValPhi && InValPhi->getParent() == BB) {
- // Add all of the input values of the input PHI as inputs of this phi.
- for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
- PN->addIncoming(InValPhi->getIncomingValue(i),
- InValPhi->getIncomingBlock(i));
- } else {
- // Otherwise, add one instance of the dominating value for each edge that
- // we will be adding.
- 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);
- }
- }
- }
-
- // The PHIs are now updated, change everything that refers to BB to use
- // DestBB and remove BB.
- 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);
- }
- BB->eraseFromParent();
- ++NumBlocksElim;
-
- DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
-}
-
-/// OptimizeNoopCopyExpression - If the specified cast instruction is a noop
-/// copy (e.g. it's casting from one pointer type to another, i32->i8 on PPC),
-/// sink it into user blocks to reduce the number of virtual
-/// registers that must be created and coalesced.
-///
-/// Return true if any changes are made.
-///
-static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI){
- // If this is a noop copy,
- EVT SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
- EVT DstVT = TLI.getValueType(CI->getType());
-
- // This is an fp<->int conversion?
- if (SrcVT.isInteger() != DstVT.isInteger())
- return false;
-
- // If this is an extension, it will be a zero or sign extension, which
- // isn't a noop.
- if (SrcVT.bitsLT(DstVT)) return false;
-
- // If these values will be promoted, find out what they will be promoted
- // to. This helps us consider truncates on PPC as noop copies when they
- // are.
- 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, after promotion, these are the same types, this is a noop copy.
- if (SrcVT != DstVT)
- return false;
-
- BasicBlock *DefBB = CI->getParent();
-
- /// InsertedCasts - Only insert a cast in each block once.
- 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);
-
- // Figure out which BB this cast is used in. For PHI's this is the
- // appropriate predecessor block.
- BasicBlock *UserBB = User->getParent();
- if (PHINode *PN = dyn_cast<PHINode>(User)) {
- UserBB = PN->getIncomingBlock(UI);
- }
-
- // Preincrement use iterator so we don't invalidate it.
- ++UI;
-
- // If this user is in the same block as the cast, don't change the cast.
- if (UserBB == DefBB) continue;
-
- // If we have already inserted a cast into this block, use it.
- CastInst *&InsertedCast = InsertedCasts[UserBB];
-
- if (!InsertedCast) {
- BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
- InsertedCast =
- CastInst::Create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
- InsertPt);
- MadeChange = true;
- }
-
- // Replace a use of the cast with a use of the new cast.
- TheUse = InsertedCast;
- ++NumCastUses;
- }
-
- // If we removed all uses, nuke the cast.
- if (CI->use_empty()) {
- CI->eraseFromParent();
- MadeChange = true;
- }
-
- return MadeChange;
-}
-
-/// OptimizeCmpExpression - sink the given CmpInst into user blocks to reduce
-/// the number of virtual registers that must be created and coalesced. This is
-/// a clear win except on targets with multiple condition code registers
-/// (PowerPC), where it might lose; some adjustment may be wanted there.
-///
-/// Return true if any changes are made.
-static bool OptimizeCmpExpression(CmpInst *CI) {
- BasicBlock *DefBB = CI->getParent();
-
- /// InsertedCmp - Only insert a cmp in each block once.
- 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);
-
- // Preincrement use iterator so we don't invalidate it.
- ++UI;
-
- // Don't bother for PHI nodes.
- if (isa<PHINode>(User))
- continue;
-
- // Figure out which BB this cmp is used in.
- BasicBlock *UserBB = User->getParent();
-
- // If this user is in the same block as the cmp, don't change the cmp.
- if (UserBB == DefBB) continue;
-
- // If we have already inserted a cmp into this block, use it.
- 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;
- }
-
- // Replace a use of the cmp with a use of the new cmp.
- TheUse = InsertedCmp;
- ++NumCmpUses;
- }
-
- // If we removed all uses, nuke the cmp.
- 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;
- }
-};
-} // end anonymous namespace
-
-bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
- BasicBlock *BB = CI->getParent();
-
- // Lower inline assembly if we can.
- // If we found an inline asm expession, and if the target knows how to
- // lower it to normal LLVM code, do so now.
- if (TLI && isa<InlineAsm>(CI->getCalledValue())) {
- if (TLI->ExpandInlineAsm(CI)) {
- // Avoid invalidating the iterator.
- CurInstIterator = BB->begin();
- // Avoid processing instructions out of order, which could cause
- // reuse before a value is defined.
- SunkAddrs.clear();
- return true;
- }
- // Sink address computing for memory operands into the block.
- if (OptimizeInlineAsmInst(CI))
- 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);
-
- replaceAndRecursivelySimplify(CI, RetVal, TLI ? TLI->getDataLayout() : 0,
- TLInfo, ModifiedDT ? 0 : DT);
-
- // 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;
- }
-
- 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;
- }
-
- // From here on out we're working with named functions.
- if (CI->getCalledFunction() == 0) return false;
-
- // We'll need DataLayout from here on out.
- const DataLayout *TD = TLI ? TLI->getDataLayout() : 0;
- if (!TD) return false;
-
- // 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);
-}
-
-/// DupRetToEnableTailCallOpts - Look for opportunities to duplicate return
-/// instructions to the predecessor to enable tail call optimizations. The
-/// case it is currently looking for is:
-/// @code
-/// bb0:
-/// %tmp0 = tail call i32 @f0()
-/// br label %return
-/// bb1:
-/// %tmp1 = tail call i32 @f1()
-/// br label %return
-/// bb2:
-/// %tmp2 = tail call i32 @f2()
-/// br label %return
-/// return:
-/// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
-/// ret i32 %retval
-/// @endcode
-///
-/// =>
-///
-/// @code
-/// bb0:
-/// %tmp0 = tail call i32 @f0()
-/// ret i32 %tmp0
-/// bb1:
-/// %tmp1 = tail call i32 @f1()
-/// ret i32 %tmp1
-/// bb2:
-/// %tmp2 = tail call i32 @f2()
-/// ret i32 %tmp2
-/// @endcode
-bool CodeGenPrepare::DupRetToEnableTailCallOpts(BasicBlock *BB) {
- if (!TLI)
- return false;
-
- ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator());
- if (!RI)
- return false;
-
- PHINode *PN = 0;
- BitCastInst *BCI = 0;
- Value *V = RI->getReturnValue();
- if (V) {
- BCI = dyn_cast<BitCastInst>(V);
- if (BCI)
- V = BCI->getOperand(0);
-
- PN = dyn_cast<PHINode>(V);
- if (!PN)
- return false;
- }
-
- if (PN && PN->getParent() != BB)
- return false;
-
- // It's not safe to eliminate the sign / zero extension of the return value.
- // See llvm::isInTailCallPosition().
- const Function *F = BB->getParent();
- AttributeSet CallerAttrs = F->getAttributes();
- if (CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt) ||
- CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
- return false;
-
- // Make sure there are no instructions between the PHI and return, or that the
- // return is the first instruction in the block.
- if (PN) {
- BasicBlock::iterator BI = BB->begin();
- do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
- if (&*BI == BCI)
- // Also skip over the bitcast.
- ++BI;
- if (&*BI != RI)
- return false;
- } else {
- BasicBlock::iterator BI = BB->begin();
- while (isa<DbgInfoIntrinsic>(BI)) ++BI;
- if (&*BI != RI)
- return false;
- }
-
- /// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
- /// call.
- SmallVector<CallInst*, 4> TailCalls;
- if (PN) {
- for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
- CallInst *CI = dyn_cast<CallInst>(PN->getIncomingValue(I));
- // Make sure the phi value is indeed produced by the tail call.
- 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);
-
- // Conservatively require the attributes of the call to match those of the
- // return. Ignore noalias because it doesn't affect the call sequence.
- AttributeSet CalleeAttrs = CS.getAttributes();
- if (AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
- removeAttribute(Attribute::NoAlias) !=
- AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
- removeAttribute(Attribute::NoAlias))
- continue;
-
- // Make sure the call instruction is followed by an unconditional branch to
- // the return block.
- BasicBlock *CallBB = CI->getParent();
- BranchInst *BI = dyn_cast<BranchInst>(CallBB->getTerminator());
- if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
- continue;
-
- // Duplicate the return into CallBB.
- (void)FoldReturnIntoUncondBranch(RI, BB, CallBB);
- ModifiedDT = Changed = true;
- ++NumRetsDup;
- }
-
- // If we eliminated all predecessors of the block, delete the block now.
- if (Changed && !BB->hasAddressTaken() && pred_begin(BB) == pred_end(BB))
- BB->eraseFromParent();
-
- return Changed;
-}
-
-//===----------------------------------------------------------------------===//
-// Memory Optimization
-//===----------------------------------------------------------------------===//
-
-namespace {
-
-/// ExtAddrMode - This is an extended version of TargetLowering::AddrMode
-/// which holds actual Value*'s for register values.
-struct ExtAddrMode : public TargetLowering::AddrMode {
- Value *BaseReg;
- Value *ScaledReg;
- ExtAddrMode() : BaseReg(0), ScaledReg(0) {}
- void print(raw_ostream &OS) const;
- void dump() const;
-
- bool operator==(const ExtAddrMode& O) const {
- return (BaseReg == O.BaseReg) && (ScaledReg == O.ScaledReg) &&
- (BaseGV == O.BaseGV) && (BaseOffs == O.BaseOffs) &&
- (HasBaseReg == O.HasBaseReg) && (Scale == O.Scale);
- }
-};
-
-#ifndef NDEBUG
-static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
- AM.print(OS);
- return OS;
-}
-#endif
-
-void ExtAddrMode::print(raw_ostream &OS) const {
- bool NeedPlus = false;
- OS << "[";
- if (BaseGV) {
- OS << (NeedPlus ? " + " : "")
- << "GV:";
- BaseGV->printAsOperand(OS, /*PrintType=*/false);
- NeedPlus = true;
- }
-
- if (BaseOffs)
- OS << (NeedPlus ? " + " : "") << BaseOffs, NeedPlus = true;
-
- if (BaseReg) {
- OS << (NeedPlus ? " + " : "")
- << "Base:";
- BaseReg->printAsOperand(OS, /*PrintType=*/false);
- NeedPlus = true;
- }
- if (Scale) {
- OS << (NeedPlus ? " + " : "")
- << Scale << "*";
- ScaledReg->printAsOperand(OS, /*PrintType=*/false);
- }
-
- OS << ']';
-}
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-void ExtAddrMode::dump() const {
- print(dbgs());
- dbgs() << '\n';
-}
-#endif
-
-/// \brief This class provides transaction based operation on the IR.
-/// Every change made through this class is recorded in the internal state and
-/// can be undone (rollback) until commit is called.
-class TypePromotionTransaction {
-
- /// \brief This represents the common interface of the individual transaction.
- /// Each class implements the logic for doing one specific modification on
- /// the IR via the TypePromotionTransaction.
- class TypePromotionAction {
- protected:
- /// The Instruction modified.
- Instruction *Inst;
-
- public:
- /// \brief Constructor of the action.
- /// The constructor performs the related action on the IR.
- TypePromotionAction(Instruction *Inst) : Inst(Inst) {}
-
- virtual ~TypePromotionAction() {}
-
- /// \brief Undo the modification done by this action.
- /// When this method is called, the IR must be in the same state as it was
- /// before this action was applied.
- /// \pre Undoing the action works if and only if the IR is in the exact same
- /// state as it was directly after this action was applied.
- virtual void undo() = 0;
-
- /// \brief Advocate every change made by this action.
- /// When the results on the IR of the action are to be kept, it is important
- /// to call this function, otherwise hidden information may be kept forever.
- virtual void commit() {
- // Nothing to be done, this action is not doing anything.
- }
- };
-
- /// \brief Utility to remember the position of an instruction.
- class InsertionHandler {
- /// Position of an instruction.
- /// Either an instruction:
- /// - Is the first in a basic block: BB is used.
- /// - Has a previous instructon: PrevInst is used.
- union {
- Instruction *PrevInst;
- BasicBlock *BB;
- } Point;
- /// Remember whether or not the instruction had a previous instruction.
- bool HasPrevInstruction;
-
- public:
- /// \brief Record the position of \p Inst.
- InsertionHandler(Instruction *Inst) {
- BasicBlock::iterator It = Inst;
- HasPrevInstruction = (It != (Inst->getParent()->begin()));
- if (HasPrevInstruction)
- Point.PrevInst = --It;
- else
- Point.BB = Inst->getParent();
- }
-
- /// \brief Insert \p Inst at the recorded position.
- void insert(Instruction *Inst) {
- if (HasPrevInstruction) {
- if (Inst->getParent())
- Inst->removeFromParent();
- Inst->insertAfter(Point.PrevInst);
- } else {
- Instruction *Position = Point.BB->getFirstInsertionPt();
- if (Inst->getParent())
- Inst->moveBefore(Position);
- else
- Inst->insertBefore(Position);
- }
- }
- };
-
- /// \brief Move an instruction before another.
- class InstructionMoveBefore : public TypePromotionAction {
- /// Original position of the instruction.
- InsertionHandler Position;
-
- public:
- /// \brief Move \p Inst before \p Before.
- InstructionMoveBefore(Instruction *Inst, Instruction *Before)
- : TypePromotionAction(Inst), Position(Inst) {
- DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Before << "\n");
- Inst->moveBefore(Before);
- }
-
- /// \brief Move the instruction back to its original position.
- void undo() {
- DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n");
- Position.insert(Inst);
- }
- };
-
- /// \brief Set the operand of an instruction with a new value.
- class OperandSetter : public TypePromotionAction {
- /// Original operand of the instruction.
- Value *Origin;
- /// Index of the modified instruction.
- unsigned Idx;
-
- public:
- /// \brief Set \p Idx operand of \p Inst with \p NewVal.
- OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
- : TypePromotionAction(Inst), Idx(Idx) {
- DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"
- << "for:" << *Inst << "\n"
- << "with:" << *NewVal << "\n");
- Origin = Inst->getOperand(Idx);
- Inst->setOperand(Idx, NewVal);
- }
-
- /// \brief Restore the original value of the instruction.
- void undo() {
- DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"
- << "for: " << *Inst << "\n"
- << "with: " << *Origin << "\n");
- Inst->setOperand(Idx, Origin);
- }
- };
-
- /// \brief Hide the operands of an instruction.
- /// Do as if this instruction was not using any of its operands.
- class OperandsHider : public TypePromotionAction {
- /// The list of original operands.
- SmallVector<Value *, 4> OriginalValues;
-
- public:
- /// \brief Remove \p Inst from the uses of the operands of \p Inst.
- OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
- DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n");
- unsigned NumOpnds = Inst->getNumOperands();
- OriginalValues.reserve(NumOpnds);
- for (unsigned It = 0; It < NumOpnds; ++It) {
- // Save the current operand.
- Value *Val = Inst->getOperand(It);
- OriginalValues.push_back(Val);
- // Set a dummy one.
- // We could use OperandSetter here, but that would implied an overhead
- // that we are not willing to pay.
- Inst->setOperand(It, UndefValue::get(Val->getType()));
- }
- }
-
- /// \brief Restore the original list of uses.
- void undo() {
- DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n");
- for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
- Inst->setOperand(It, OriginalValues[It]);
- }
- };
-
- /// \brief Build a truncate instruction.
- class TruncBuilder : public TypePromotionAction {
- public:
- /// \brief Build a truncate instruction of \p Opnd producing a \p Ty
- /// result.
- /// trunc Opnd to Ty.
- TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
- IRBuilder<> Builder(Opnd);
- Inst = cast<Instruction>(Builder.CreateTrunc(Opnd, Ty, "promoted"));
- DEBUG(dbgs() << "Do: TruncBuilder: " << *Inst << "\n");
- }
-
- /// \brief Get the built instruction.
- Instruction *getBuiltInstruction() { return Inst; }
-
- /// \brief Remove the built instruction.
- void undo() {
- DEBUG(dbgs() << "Undo: TruncBuilder: " << *Inst << "\n");
- Inst->eraseFromParent();
- }
- };
-
- /// \brief Build a sign extension instruction.
- class SExtBuilder : public TypePromotionAction {
- public:
- /// \brief Build a sign extension instruction of \p Opnd producing a \p Ty
- /// result.
- /// sext Opnd to Ty.
- SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
- : TypePromotionAction(Inst) {
- IRBuilder<> Builder(InsertPt);
- Inst = cast<Instruction>(Builder.CreateSExt(Opnd, Ty, "promoted"));
- DEBUG(dbgs() << "Do: SExtBuilder: " << *Inst << "\n");
- }
-
- /// \brief Get the built instruction.
- Instruction *getBuiltInstruction() { return Inst; }
-
- /// \brief Remove the built instruction.
- void undo() {
- DEBUG(dbgs() << "Undo: SExtBuilder: " << *Inst << "\n");
- Inst->eraseFromParent();
- }
- };
-
- /// \brief Mutate an instruction to another type.
- class TypeMutator : public TypePromotionAction {
- /// Record the original type.
- Type *OrigTy;
-
- public:
- /// \brief Mutate the type of \p Inst into \p NewTy.
- TypeMutator(Instruction *Inst, Type *NewTy)
- : TypePromotionAction(Inst), OrigTy(Inst->getType()) {
- DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTy
- << "\n");
- Inst->mutateType(NewTy);
- }
-
- /// \brief Mutate the instruction back to its original type.
- void undo() {
- DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTy
- << "\n");
- Inst->mutateType(OrigTy);
- }
- };
-
- /// \brief Replace the uses of an instruction by another instruction.
- class UsesReplacer : public TypePromotionAction {
- /// Helper structure to keep track of the replaced uses.
- struct InstructionAndIdx {
- /// The instruction using the instruction.
- Instruction *Inst;
- /// The index where this instruction is used for Inst.
- unsigned Idx;
- InstructionAndIdx(Instruction *Inst, unsigned Idx)
- : Inst(Inst), Idx(Idx) {}
- };
-
- /// Keep track of the original uses (pair Instruction, Index).
- SmallVector<InstructionAndIdx, 4> OriginalUses;
- typedef SmallVectorImpl<InstructionAndIdx>::iterator use_iterator;
-
- public:
- /// \brief Replace all the use of \p Inst by \p New.
- UsesReplacer(Instruction *Inst, Value *New) : TypePromotionAction(Inst) {
- DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *New
- << "\n");
- // Record the original uses.
- for (Value::use_iterator UseIt = Inst->use_begin(),
- EndIt = Inst->use_end();
- UseIt != EndIt; ++UseIt) {
- Instruction *Use = cast<Instruction>(*UseIt);
- OriginalUses.push_back(InstructionAndIdx(Use, UseIt.getOperandNo()));
- }
- // Now, we can replace the uses.
- Inst->replaceAllUsesWith(New);
- }
-
- /// \brief Reassign the original uses of Inst to Inst.
- void undo() {
- DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n");
- for (use_iterator UseIt = OriginalUses.begin(),
- EndIt = OriginalUses.end();
- UseIt != EndIt; ++UseIt) {
- UseIt->Inst->setOperand(UseIt->Idx, Inst);
- }
- }
- };
-
- /// \brief Remove an instruction from the IR.
- class InstructionRemover : public TypePromotionAction {
- /// Original position of the instruction.
- InsertionHandler Inserter;
- /// Helper structure to hide all the link to the instruction. In other
- /// words, this helps to do as if the instruction was removed.
- OperandsHider Hider;
- /// Keep track of the uses replaced, if any.
- UsesReplacer *Replacer;
-
- public:
- /// \brief Remove all reference of \p Inst and optinally replace all its
- /// uses with New.
- /// \pre If !Inst->use_empty(), then New != NULL
- InstructionRemover(Instruction *Inst, Value *New = NULL)
- : TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
- Replacer(NULL) {
- if (New)
- Replacer = new UsesReplacer(Inst, New);
- DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n");
- Inst->removeFromParent();
- }
-
- ~InstructionRemover() { delete Replacer; }
-
- /// \brief Really remove the instruction.
- void commit() { delete Inst; }
-
- /// \brief Resurrect the instruction and reassign it to the proper uses if
- /// new value was provided when build this action.
- void undo() {
- DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n");
- Inserter.insert(Inst);
- if (Replacer)
- Replacer->undo();
- Hider.undo();
- }
- };
-
-public:
- /// Restoration point.
- /// The restoration point is a pointer to an action instead of an iterator
- /// because the iterator may be invalidated but not the pointer.
- typedef const TypePromotionAction *ConstRestorationPt;
- /// Advocate every changes made in that transaction.
- void commit();
- /// Undo all the changes made after the given point.
- void rollback(ConstRestorationPt Point);
- /// Get the current restoration point.
- ConstRestorationPt getRestorationPoint() const;
-
- /// \name API for IR modification with state keeping to support rollback.
- /// @{
- /// Same as Instruction::setOperand.
- void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);
- /// Same as Instruction::eraseFromParent.
- void eraseInstruction(Instruction *Inst, Value *NewVal = NULL);
- /// Same as Value::replaceAllUsesWith.
- void replaceAllUsesWith(Instruction *Inst, Value *New);
- /// Same as Value::mutateType.
- void mutateType(Instruction *Inst, Type *NewTy);
- /// Same as IRBuilder::createTrunc.
- Instruction *createTrunc(Instruction *Opnd, Type *Ty);
- /// Same as IRBuilder::createSExt.
- Instruction *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);
- /// Same as Instruction::moveBefore.
- void moveBefore(Instruction *Inst, Instruction *Before);
- /// @}
-
- ~TypePromotionTransaction();
-
-private:
- /// The ordered list of actions made so far.
- SmallVector<TypePromotionAction *, 16> Actions;
- typedef SmallVectorImpl<TypePromotionAction *>::iterator CommitPt;
-};
-
-void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
- Value *NewVal) {
- Actions.push_back(
- new TypePromotionTransaction::OperandSetter(Inst, Idx, NewVal));
-}
-
-void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
- Value *NewVal) {
- Actions.push_back(
- new TypePromotionTransaction::InstructionRemover(Inst, NewVal));
-}
-
-void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
- Value *New) {
- Actions.push_back(new TypePromotionTransaction::UsesReplacer(Inst, New));
-}
-
-void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
- Actions.push_back(new TypePromotionTransaction::TypeMutator(Inst, NewTy));
-}
-
-Instruction *TypePromotionTransaction::createTrunc(Instruction *Opnd,
- Type *Ty) {
- TruncBuilder *TB = new TruncBuilder(Opnd, Ty);
- Actions.push_back(TB);
- return TB->getBuiltInstruction();
-}
-
-Instruction *TypePromotionTransaction::createSExt(Instruction *Inst,
- Value *Opnd, Type *Ty) {
- SExtBuilder *SB = new SExtBuilder(Inst, Opnd, Ty);
- Actions.push_back(SB);
- return SB->getBuiltInstruction();
-}
-
-void TypePromotionTransaction::moveBefore(Instruction *Inst,
- Instruction *Before) {
- Actions.push_back(
- new TypePromotionTransaction::InstructionMoveBefore(Inst, Before));
-}
-
-TypePromotionTransaction::ConstRestorationPt
-TypePromotionTransaction::getRestorationPoint() const {
- return Actions.rbegin() != Actions.rend() ? *Actions.rbegin() : NULL;
-}
-
-void TypePromotionTransaction::commit() {
- for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt;
- ++It) {
- (*It)->commit();
- delete *It;
- }
- Actions.clear();
-}
-
-void TypePromotionTransaction::rollback(
- TypePromotionTransaction::ConstRestorationPt Point) {
- while (!Actions.empty() && Point != (*Actions.rbegin())) {
- TypePromotionAction *Curr = Actions.pop_back_val();
- Curr->undo();
- delete Curr;
- }
-}
-
-TypePromotionTransaction::~TypePromotionTransaction() {
- for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt; ++It)
- delete *It;
- Actions.clear();
-}
-
-/// \brief A helper class for matching addressing modes.
-///
-/// This encapsulates the logic for matching the target-legal addressing modes.
-class AddressingModeMatcher {
- SmallVectorImpl<Instruction*> &AddrModeInsts;
- const TargetLowering &TLI;
-
- /// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
- /// the memory instruction that we're computing this address for.
- Type *AccessTy;
- Instruction *MemoryInst;
-
- /// AddrMode - This is the addressing mode that we're building up. This is
- /// part of the return value of this addressing mode matching stuff.
- ExtAddrMode &AddrMode;
-
- /// The truncate instruction inserted by other CodeGenPrepare optimizations.
- const SetOfInstrs &InsertedTruncs;
- /// A map from the instructions to their type before promotion.
- InstrToOrigTy &PromotedInsts;
- /// The ongoing transaction where every action should be registered.
- TypePromotionTransaction &TPT;
-
- /// IgnoreProfitability - This is set to true when we should not do
- /// profitability checks. When true, IsProfitableToFoldIntoAddressingMode
- /// always returns true.
- bool IgnoreProfitability;
-
- AddressingModeMatcher(SmallVectorImpl<Instruction*> &AMI,
- const TargetLowering &T, Type *AT,
- Instruction *MI, ExtAddrMode &AM,
- const SetOfInstrs &InsertedTruncs,
- InstrToOrigTy &PromotedInsts,
- TypePromotionTransaction &TPT)
- : AddrModeInsts(AMI), TLI(T), AccessTy(AT), MemoryInst(MI), AddrMode(AM),
- InsertedTruncs(InsertedTruncs), PromotedInsts(PromotedInsts), TPT(TPT) {
- IgnoreProfitability = false;
- }
-public:
-
- /// Match - Find the maximal addressing mode that a load/store of V can fold,
- /// give an access type of AccessTy. This returns a list of involved
- /// instructions in AddrModeInsts.
- /// \p InsertedTruncs The truncate instruction inserted by other
- /// CodeGenPrepare
- /// optimizations.
- /// \p PromotedInsts maps the instructions to their type before promotion.
- /// \p The ongoing transaction where every action should be registered.
- static ExtAddrMode Match(Value *V, Type *AccessTy,
- Instruction *MemoryInst,
- SmallVectorImpl<Instruction*> &AddrModeInsts,
- const TargetLowering &TLI,
- const SetOfInstrs &InsertedTruncs,
- InstrToOrigTy &PromotedInsts,
- TypePromotionTransaction &TPT) {
- ExtAddrMode Result;
-
- bool Success = AddressingModeMatcher(AddrModeInsts, TLI, AccessTy,
- MemoryInst, Result, InsertedTruncs,
- PromotedInsts, TPT).MatchAddr(V, 0);
- (void)Success; assert(Success && "Couldn't select *anything*?");
- return Result;
- }
-private:
- bool MatchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
- bool MatchAddr(Value *V, unsigned Depth);
- bool MatchOperationAddr(User *Operation, unsigned Opcode, unsigned Depth,
- bool *MovedAway = NULL);
- bool IsProfitableToFoldIntoAddressingMode(Instruction *I,
- ExtAddrMode &AMBefore,
- ExtAddrMode &AMAfter);
- bool ValueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
- bool IsPromotionProfitable(unsigned MatchedSize, unsigned SizeWithPromotion,
- Value *PromotedOperand) const;
-};
-
-/// MatchScaledValue - Try adding ScaleReg*Scale to the current addressing mode.
-/// Return true and update AddrMode if this addr mode is legal for the target,
-/// false if not.
-bool AddressingModeMatcher::MatchScaledValue(Value *ScaleReg, int64_t Scale,
- unsigned Depth) {
- // If Scale is 1, then this is the same as adding ScaleReg to the addressing
- // mode. Just process that directly.
- if (Scale == 1)
- return MatchAddr(ScaleReg, Depth);
-
- // If the scale is 0, it takes nothing to add this.
- if (Scale == 0)
- return true;
-
- // If we already have a scale of this value, we can add to it, otherwise, we
- // need an available scale field.
- if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
- return false;
-
- ExtAddrMode TestAddrMode = AddrMode;
-
- // Add scale to turn X*4+X*3 -> X*7. This could also do things like
- // [A+B + A*7] -> [B+A*8].
- TestAddrMode.Scale += Scale;
- TestAddrMode.ScaledReg = ScaleReg;
-
- // If the new address isn't legal, bail out.
- if (!TLI.isLegalAddressingMode(TestAddrMode, AccessTy))
- return false;
-
- // It was legal, so commit it.
- AddrMode = TestAddrMode;
-
- // Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
- // to see if ScaleReg is actually X+C. If so, we can turn this into adding
- // X*Scale + C*Scale to addr mode.
- ConstantInt *CI = 0; Value *AddLHS = 0;
- if (isa<Instruction>(ScaleReg) && // not a constant expr.
- match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI)))) {
- TestAddrMode.ScaledReg = AddLHS;
- TestAddrMode.BaseOffs += CI->getSExtValue()*TestAddrMode.Scale;
-
- // If this addressing mode is legal, commit it and remember that we folded
- // this instruction.
- if (TLI.isLegalAddressingMode(TestAddrMode, AccessTy)) {
- AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
- AddrMode = TestAddrMode;
- return true;
- }
- }
-
- // Otherwise, not (x+c)*scale, just return what we have.
- return true;
-}
-
-/// MightBeFoldableInst - This is a little filter, which returns true if an
-/// addressing computation involving I might be folded into a load/store
-/// accessing it. This doesn't need to be perfect, but needs to accept at least
-/// the set of instructions that MatchOperationAddr can.
-static bool MightBeFoldableInst(Instruction *I) {
- switch (I->getOpcode()) {
- case Instruction::BitCast:
- // Don't touch identity bitcasts.
- if (I->getType() == I->getOperand(0)->getType())
- return false;
- return I->getType()->isPointerTy() || I->getType()->isIntegerTy();
- case Instruction::PtrToInt:
- // PtrToInt is always a noop, as we know that the int type is pointer sized.
- return true;
- case Instruction::IntToPtr:
- // We know the input is intptr_t, so this is foldable.
- return true;
- case Instruction::Add:
- return true;
- case Instruction::Mul:
- case Instruction::Shl:
- // Can only handle X*C and X << C.
- return isa<ConstantInt>(I->getOperand(1));
- case Instruction::GetElementPtr:
- return true;
- default:
- return false;
- }
-}
-
-/// \brief Hepler class to perform type promotion.
-class TypePromotionHelper {
- /// \brief Utility function to check whether or not a sign extension of
- /// \p Inst with \p ConsideredSExtType can be moved through \p Inst by either
- /// using the operands of \p Inst or promoting \p Inst.
- /// In other words, check if:
- /// sext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredSExtType.
- /// #1 Promotion applies:
- /// ConsideredSExtType Inst (sext opnd1 to ConsideredSExtType, ...).
- /// #2 Operand reuses:
- /// sext opnd1 to ConsideredSExtType.
- /// \p PromotedInsts maps the instructions to their type before promotion.
- static bool canGetThrough(const Instruction *Inst, Type *ConsideredSExtType,
- const InstrToOrigTy &PromotedInsts);
-
- /// \brief Utility function to determine if \p OpIdx should be promoted when
- /// promoting \p Inst.
- static bool shouldSExtOperand(const Instruction *Inst, int OpIdx) {
- if (isa<SelectInst>(Inst) && OpIdx == 0)
- return false;
- return true;
- }
-
- /// \brief Utility function to promote the operand of \p SExt when this
- /// operand is a promotable 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 SExt.
- /// Should never be called directly.
- /// \return The promoted value which is used instead of SExt.
- static Value *promoteOperandForTruncAndSExt(Instruction *SExt,
- TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts);
-
- /// \brief Utility function to promote the operand of \p SExt 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 SExt.
- /// Should never be called directly.
- /// \return The promoted value which is used instead of SExt.
- static Value *promoteOperandForOther(Instruction *SExt,
- TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts);
-
-public:
- /// Type for the utility function that promotes the operand of SExt.
- typedef Value *(*Action)(Instruction *SExt, TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts);
- /// \brief Given a sign extend instruction \p SExt, return the approriate
- /// action to promote the operand of \p SExt instead of using SExt.
- /// \return NULL if no promotable action is possible with the current
- /// sign extension.
- /// \p InsertedTruncs keeps track of all the truncate instructions inserted by
- /// the others CodeGenPrepare optimizations. This information is important
- /// because we do not want to promote these instructions as CodeGenPrepare
- /// will reinsert them later. Thus creating an infinite loop: create/remove.
- /// \p PromotedInsts maps the instructions to their type before promotion.
- static Action getAction(Instruction *SExt, const SetOfInstrs &InsertedTruncs,
- const TargetLowering &TLI,
- const InstrToOrigTy &PromotedInsts);
-};
-
-bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
- Type *ConsideredSExtType,
- const InstrToOrigTy &PromotedInsts) {
- // We can always get through sext.
- if (isa<SExtInst>(Inst))
- return true;
-
- // We can get through binary operator, if it is legal. In other words, the
- // binary operator must have a nuw or nsw flag.
- const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst);
- if (BinOp && isa<OverflowingBinaryOperator>(BinOp) &&
- (BinOp->hasNoUnsignedWrap() || BinOp->hasNoSignedWrap()))
- return true;
-
- // Check if we can do the following simplification.
- // sext(trunc(sext)) --> sext
- if (!isa<TruncInst>(Inst))
- return false;
-
- Value *OpndVal = Inst->getOperand(0);
- // Check if we can use this operand in the sext.
- // If the type is larger than the result type of the sign extension,
- // we cannot.
- if (OpndVal->getType()->getIntegerBitWidth() >
- ConsideredSExtType->getIntegerBitWidth())
- return false;
-
- // If the operand of the truncate is not an instruction, we will not have
- // any information on the dropped bits.
- // (Actually we could for constant but it is not worth the extra logic).
- Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
- if (!Opnd)
- return false;
-
- // Check if the source of the type is narrow enough.
- // I.e., check that trunc just drops sign extended bits.
- // #1 get the type of the operand.
- const Type *OpndType;
- InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
- if (It != PromotedInsts.end())
- OpndType = It->second;
- else if (isa<SExtInst>(Opnd))
- OpndType = cast<Instruction>(Opnd)->getOperand(0)->getType();
- else
- return false;
-
- // #2 check that the truncate just drop sign extended bits.
- if (Inst->getType()->getIntegerBitWidth() >= OpndType->getIntegerBitWidth())
- return true;
-
- return false;
-}
-
-TypePromotionHelper::Action TypePromotionHelper::getAction(
- Instruction *SExt, const SetOfInstrs &InsertedTruncs,
- const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
- Instruction *SExtOpnd = dyn_cast<Instruction>(SExt->getOperand(0));
- Type *SExtTy = SExt->getType();
- // If the operand of the sign extension is not an instruction, we cannot
- // get through.
- // If it, check we can get through.
- if (!SExtOpnd || !canGetThrough(SExtOpnd, SExtTy, PromotedInsts))
- return NULL;
-
- // Do not promote if the operand has been added by codegenprepare.
- // Otherwise, it means we are undoing an optimization that is likely to be
- // redone, thus causing potential infinite loop.
- if (isa<TruncInst>(SExtOpnd) && InsertedTruncs.count(SExtOpnd))
- return NULL;
-
- // SExt or Trunc instructions.
- // Return the related handler.
- if (isa<SExtInst>(SExtOpnd) || isa<TruncInst>(SExtOpnd))
- return promoteOperandForTruncAndSExt;
-
- // Regular instruction.
- // Abort early if we will have to insert non-free instructions.
- if (!SExtOpnd->hasOneUse() &&
- !TLI.isTruncateFree(SExtTy, SExtOpnd->getType()))
- return NULL;
- return promoteOperandForOther;
-}
-
-Value *TypePromotionHelper::promoteOperandForTruncAndSExt(
- llvm::Instruction *SExt, TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts) {
- // 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));
- // Replace sext(trunc(opnd)) or sext(sext(opnd))
- // => sext(opnd).
- TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
- CreatedInsts = 0;
-
- // Remove dead code.
- if (SExtOpnd->use_empty())
- TPT.eraseInstruction(SExtOpnd);
-
- // Check if the sext is still needed.
- if (SExt->getType() != SExt->getOperand(0)->getType())
- return SExt;
-
- // At this point we have: sext ty opnd to ty.
- // Reassign the uses of SExt to the opnd and remove SExt.
- Value *NextVal = SExt->getOperand(0);
- TPT.eraseInstruction(SExt, NextVal);
- return NextVal;
-}
-
-Value *
-TypePromotionHelper::promoteOperandForOther(Instruction *SExt,
- TypePromotionTransaction &TPT,
- InstrToOrigTy &PromotedInsts,
- unsigned &CreatedInsts) {
- // 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));
- CreatedInsts = 0;
- if (!SExtOpnd->hasOneUse()) {
- // SExtOpnd will be promoted.
- // All its uses, but SExt, will need to use a truncated value of the
- // promoted version.
- // Create the truncate now.
- Instruction *Trunc = TPT.createTrunc(SExt, SExtOpnd->getType());
- Trunc->removeFromParent();
- // Insert it just after the definition.
- Trunc->insertAfter(SExtOpnd);
-
- TPT.replaceAllUsesWith(SExtOpnd, Trunc);
- // Restore the operand of SExt (which has been replace by the previous call
- // to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
- TPT.setOperand(SExt, 0, SExtOpnd);
- }
-
- // Get through the Instruction:
- // 1. Update its type.
- // 2. Replace the uses of SExt by Inst.
- // 3. Sign extend each operand that needs to be sign extended.
-
- // Remember the original type of the instruction before promotion.
- // This is useful to know that the high bits are sign extended bits.
- PromotedInsts.insert(
- std::pair<Instruction *, Type *>(SExtOpnd, SExtOpnd->getType()));
- // Step #1.
- TPT.mutateType(SExtOpnd, SExt->getType());
- // Step #2.
- TPT.replaceAllUsesWith(SExt, SExtOpnd);
- // Step #3.
- Instruction *SExtForOpnd = SExt;
-
- DEBUG(dbgs() << "Propagate SExt to operands\n");
- for (int OpIdx = 0, EndOpIdx = SExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
- ++OpIdx) {
- DEBUG(dbgs() << "Operand:\n" << *(SExtOpnd->getOperand(OpIdx)) << '\n');
- if (SExtOpnd->getOperand(OpIdx)->getType() == SExt->getType() ||
- !shouldSExtOperand(SExtOpnd, OpIdx)) {
- DEBUG(dbgs() << "No need to propagate\n");
- continue;
- }
- // Check if we can statically sign extend the operand.
- Value *Opnd = SExtOpnd->getOperand(OpIdx);
- if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
- DEBUG(dbgs() << "Statically sign extend\n");
- TPT.setOperand(
- SExtOpnd, OpIdx,
- ConstantInt::getSigned(SExt->getType(), Cst->getSExtValue()));
- continue;
- }
- // UndefValue are typed, so we have to statically sign extend them.
- if (isa<UndefValue>(Opnd)) {
- DEBUG(dbgs() << "Statically sign extend\n");
- TPT.setOperand(SExtOpnd, OpIdx, UndefValue::get(SExt->getType()));
- continue;
- }
-
- // Otherwise we have to explicity sign extend the operand.
- // Check if SExt was reused to sign extend an operand.
- if (!SExtForOpnd) {
- // If yes, create a new one.
- DEBUG(dbgs() << "More operands to sext\n");
- SExtForOpnd = TPT.createSExt(SExt, Opnd, SExt->getType());
- ++CreatedInsts;
- }
-
- TPT.setOperand(SExtForOpnd, 0, Opnd);
-
- // Move the sign extension before the insertion point.
- TPT.moveBefore(SExtForOpnd, SExtOpnd);
- TPT.setOperand(SExtOpnd, OpIdx, SExtForOpnd);
- // If more sext are required, new instructions will have to be created.
- SExtForOpnd = NULL;
- }
- if (SExtForOpnd == SExt) {
- DEBUG(dbgs() << "Sign extension is useless now\n");
- TPT.eraseInstruction(SExt);
- }
- return SExtOpnd;
-}
-
-/// IsPromotionProfitable - Check whether or not promoting an instruction
-/// to a wider type was profitable.
-/// \p MatchedSize gives the number of instructions that have been matched
-/// in the addressing mode after the promotion was applied.
-/// \p SizeWithPromotion gives the number of created instructions for
-/// the promotion plus the number of instructions that have been
-/// matched in the addressing mode before the promotion.
-/// \p PromotedOperand is the value that has been promoted.
-/// \return True if the promotion is profitable, false otherwise.
-bool
-AddressingModeMatcher::IsPromotionProfitable(unsigned MatchedSize,
- unsigned SizeWithPromotion,
- Value *PromotedOperand) const {
- // We folded less instructions than what we created to promote the operand.
- // This is not profitable.
- if (MatchedSize < SizeWithPromotion)
- return false;
- if (MatchedSize > SizeWithPromotion)
- return true;
- // 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;
- return TLI.isOperationLegalOrCustom(PromotedInst->getOpcode(),
- EVT::getEVT(PromotedInst->getType()));
-}
-
-/// MatchOperationAddr - Given an instruction or constant expr, see if we can
-/// fold the operation into the addressing mode. If so, update the addressing
-/// mode and return true, otherwise return false without modifying AddrMode.
-/// If \p MovedAway is not NULL, it contains the information of whether or
-/// not AddrInst has to be folded into the addressing mode on success.
-/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
-/// because it has been moved away.
-/// Thus AddrInst must not be added in the matched instructions.
-/// This state can happen when AddrInst is a sext, since it may be moved away.
-/// Therefore, AddrInst may not be valid when MovedAway is true and it must
-/// not be referenced anymore.
-bool AddressingModeMatcher::MatchOperationAddr(User *AddrInst, unsigned Opcode,
- unsigned Depth,
- bool *MovedAway) {
- // Avoid exponential behavior on extremely deep expression trees.
- if (Depth >= 5) return false;
-
- // By default, all matched instructions stay in place.
- if (MovedAway)
- *MovedAway = false;
-
- switch (Opcode) {
- case Instruction::PtrToInt:
- // PtrToInt is always a noop, as we know that the int type is pointer sized.
- return MatchAddr(AddrInst->getOperand(0), Depth);
- case Instruction::IntToPtr:
- // This inttoptr is a no-op if the integer type is pointer sized.
- if (TLI.getValueType(AddrInst->getOperand(0)->getType()) ==
- TLI.getPointerTy(AddrInst->getType()->getPointerAddressSpace()))
- return MatchAddr(AddrInst->getOperand(0), Depth);
- return false;
- case Instruction::BitCast:
- // BitCast is always a noop, and we can handle it as long as it is
- // int->int or pointer->pointer (we don't want int<->fp or something).
- if ((AddrInst->getOperand(0)->getType()->isPointerTy() ||
- AddrInst->getOperand(0)->getType()->isIntegerTy()) &&
- // Don't touch identity bitcasts. These were probably put here by LSR,
- // and we don't want to mess around with them. Assume it knows what it
- // is doing.
- AddrInst->getOperand(0)->getType() != AddrInst->getType())
- return MatchAddr(AddrInst->getOperand(0), Depth);
- return false;
- case Instruction::Add: {
- // Check to see if we can merge in the RHS then the LHS. If so, we win.
- ExtAddrMode BackupAddrMode = AddrMode;
- unsigned OldSize = AddrModeInsts.size();
- // Start a transaction at this point.
- // The LHS may match but not the RHS.
- // Therefore, we need a higher level restoration point to undo partially
- // matched operation.
- TypePromotionTransaction::ConstRestorationPt LastKnownGood =
- TPT.getRestorationPoint();
-
- if (MatchAddr(AddrInst->getOperand(1), Depth+1) &&
- MatchAddr(AddrInst->getOperand(0), Depth+1))
- return true;
-
- // Restore the old addr mode info.
- AddrMode = BackupAddrMode;
- AddrModeInsts.resize(OldSize);
- TPT.rollback(LastKnownGood);
-
- // Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
- if (MatchAddr(AddrInst->getOperand(0), Depth+1) &&
- MatchAddr(AddrInst->getOperand(1), Depth+1))
- return true;
-
- // Otherwise we definitely can't merge the ADD in.
- AddrMode = BackupAddrMode;
- AddrModeInsts.resize(OldSize);
- TPT.rollback(LastKnownGood);
- break;
- }
- //case Instruction::Or:
- // TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
- //break;
- case Instruction::Mul:
- case Instruction::Shl: {
- // Can only handle X*C and X << C.
- ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
- if (!RHS) return false;
- int64_t Scale = RHS->getSExtValue();
- if (Opcode == Instruction::Shl)
- Scale = 1LL << Scale;
-
- return MatchScaledValue(AddrInst->getOperand(0), Scale, Depth);
- }
- case Instruction::GetElementPtr: {
- // Scan the GEP. We check it if it contains constant offsets and at most
- // one variable offset.
- int VariableOperand = -1;
- unsigned VariableScale = 0;
-
- int64_t ConstantOffset = 0;
- const DataLayout *TD = TLI.getDataLayout();
- gep_type_iterator GTI = gep_type_begin(AddrInst);
- for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
- if (StructType *STy = dyn_cast<StructType>(*GTI)) {
- const StructLayout *SL = TD->getStructLayout(STy);
- unsigned Idx =
- cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
- ConstantOffset += SL->getElementOffset(Idx);
- } else {
- uint64_t TypeSize = TD->getTypeAllocSize(GTI.getIndexedType());
- if (ConstantInt *CI = dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
- ConstantOffset += CI->getSExtValue()*TypeSize;
- } else if (TypeSize) { // Scales of zero don't do anything.
- // We only allow one variable index at the moment.
- if (VariableOperand != -1)
- return false;
-
- // Remember the variable index.
- VariableOperand = i;
- VariableScale = TypeSize;
- }
- }
- }
-
- // A common case is for the GEP to only do a constant offset. In this case,
- // just add it to the disp field and check validity.
- if (VariableOperand == -1) {
- AddrMode.BaseOffs += ConstantOffset;
- if (ConstantOffset == 0 || TLI.isLegalAddressingMode(AddrMode, AccessTy)){
- // Check to see if we can fold the base pointer in too.
- if (MatchAddr(AddrInst->getOperand(0), Depth+1))
- return true;
- }
- AddrMode.BaseOffs -= ConstantOffset;
- return false;
- }
-
- // Save the valid addressing mode in case we can't match.
- ExtAddrMode BackupAddrMode = AddrMode;
- unsigned OldSize = AddrModeInsts.size();
-
- // See if the scale and offset amount is valid for this target.
- AddrMode.BaseOffs += ConstantOffset;
-
- // Match the base operand of the GEP.
- if (!MatchAddr(AddrInst->getOperand(0), Depth+1)) {
- // If it couldn't be matched, just stuff the value in a register.
- if (AddrMode.HasBaseReg) {
- AddrMode = BackupAddrMode;
- AddrModeInsts.resize(OldSize);
- return false;
- }
- AddrMode.HasBaseReg = true;
- AddrMode.BaseReg = AddrInst->getOperand(0);
- }
-
- // Match the remaining variable portion of the GEP.
- if (!MatchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
- Depth)) {
- // If it couldn't be matched, try stuffing the base into a register
- // instead of matching it, and retrying the match of the scale.
- AddrMode = BackupAddrMode;
- AddrModeInsts.resize(OldSize);
- if (AddrMode.HasBaseReg)
- return false;
- AddrMode.HasBaseReg = true;
- AddrMode.BaseReg = AddrInst->getOperand(0);
- AddrMode.BaseOffs += ConstantOffset;
- if (!MatchScaledValue(AddrInst->getOperand(VariableOperand),
- VariableScale, Depth)) {
- // If even that didn't work, bail.
- AddrMode = BackupAddrMode;
- AddrModeInsts.resize(OldSize);
- return false;
- }
- }
-
- return true;
- }
- case Instruction::SExt: {
- // Try to move this sext out of the way of the addressing mode.
- Instruction *SExt = cast<Instruction>(AddrInst);
- // Ask for a method for doing so.
- TypePromotionHelper::Action TPH = TypePromotionHelper::getAction(
- SExt, InsertedTruncs, TLI, PromotedInsts);
- if (!TPH)
- return false;
-
- TypePromotionTransaction::ConstRestorationPt LastKnownGood =
- TPT.getRestorationPoint();
- unsigned CreatedInsts = 0;
- Value *PromotedOperand = TPH(SExt, TPT, PromotedInsts, CreatedInsts);
- // 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.
- // E.g.,
- // op = add opnd, 1
- // idx = sext op
- // addr = gep base, idx
- // is now:
- // promotedOpnd = sext opnd <- no match here
- // op = promoted_add promotedOpnd, 1 <- match (later in recursive calls)
- // addr = gep base, op <- match
- if (MovedAway)
- *MovedAway = true;
-
- assert(PromotedOperand &&
- "TypePromotionHelper should have filtered out those cases");
-
- ExtAddrMode BackupAddrMode = AddrMode;
- unsigned OldSize = AddrModeInsts.size();
-
- if (!MatchAddr(PromotedOperand, Depth) ||
- !IsPromotionProfitable(AddrModeInsts.size(), OldSize + CreatedInsts,
- PromotedOperand)) {
- AddrMode = BackupAddrMode;
- AddrModeInsts.resize(OldSize);
- DEBUG(dbgs() << "Sign extension does not pay off: rollback\n");
- TPT.rollback(LastKnownGood);
- return false;
- }
- return true;
- }
- }
- return false;
-}
-
-/// MatchAddr - If we can, try to add the value of 'Addr' into the current
-/// addressing mode. If Addr can't be added to AddrMode this returns false and
-/// leaves AddrMode unmodified. This assumes that Addr is either a pointer type
-/// or intptr_t for the target.
-///
-bool AddressingModeMatcher::MatchAddr(Value *Addr, unsigned Depth) {
- // Start a transaction at this point that we will rollback if the matching
- // fails.
- TypePromotionTransaction::ConstRestorationPt LastKnownGood =
- TPT.getRestorationPoint();
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
- // Fold in immediates if legal for the target.
- AddrMode.BaseOffs += CI->getSExtValue();
- if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
- return true;
- AddrMode.BaseOffs -= CI->getSExtValue();
- } else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
- // If this is a global variable, try to fold it into the addressing mode.
- if (AddrMode.BaseGV == 0) {
- AddrMode.BaseGV = GV;
- if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
- return true;
- AddrMode.BaseGV = 0;
- }
- } else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
- ExtAddrMode BackupAddrMode = AddrMode;
- unsigned OldSize = AddrModeInsts.size();
-
- // Check to see if it is possible to fold this operation.
- bool MovedAway = false;
- if (MatchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
- // This instruction may have been move away. If so, there is nothing
- // to check here.
- if (MovedAway)
- return true;
- // Okay, it's possible to fold this. Check to see if it is actually
- // *profitable* to do so. We use a simple cost model to avoid increasing
- // register pressure too much.
- if (I->hasOneUse() ||
- IsProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
- AddrModeInsts.push_back(I);
- return true;
- }
-
- // It isn't profitable to do this, roll back.
- //cerr << "NOT FOLDING: " << *I;
- AddrMode = BackupAddrMode;
- AddrModeInsts.resize(OldSize);
- TPT.rollback(LastKnownGood);
- }
- } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
- if (MatchOperationAddr(CE, CE->getOpcode(), Depth))
- return true;
- TPT.rollback(LastKnownGood);
- } else if (isa<ConstantPointerNull>(Addr)) {
- // Null pointer gets folded without affecting the addressing mode.
- return true;
- }
-
- // Worse case, the target should support [reg] addressing modes. :)
- if (!AddrMode.HasBaseReg) {
- AddrMode.HasBaseReg = true;
- AddrMode.BaseReg = Addr;
- // Still check for legality in case the target supports [imm] but not [i+r].
- if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
- return true;
- AddrMode.HasBaseReg = false;
- AddrMode.BaseReg = 0;
- }
-
- // If the base register is already taken, see if we can do [r+r].
- if (AddrMode.Scale == 0) {
- AddrMode.Scale = 1;
- AddrMode.ScaledReg = Addr;
- if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
- return true;
- AddrMode.Scale = 0;
- AddrMode.ScaledReg = 0;
- }
- // Couldn't match.
- TPT.rollback(LastKnownGood);
- return false;
-}
-
-/// IsOperandAMemoryOperand - Check to see if all uses of OpVal by the specified
-/// inline asm call are due to memory operands. If so, return true, otherwise
-/// return false.
-static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
- const TargetLowering &TLI) {
- TargetLowering::AsmOperandInfoVector TargetConstraints = TLI.ParseConstraints(ImmutableCallSite(CI));
- for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
- TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
-
- // Compute the constraint code and ConstraintType to use.
- TLI.ComputeConstraintToUse(OpInfo, SDValue());
-
- // If this asm operand is our Value*, and if it isn't an indirect memory
- // operand, we can't fold it!
- if (OpInfo.CallOperandVal == OpVal &&
- (OpInfo.ConstraintType != TargetLowering::C_Memory ||
- !OpInfo.isIndirect))
- return false;
- }
-
- return true;
-}
-
-/// FindAllMemoryUses - Recursively walk all the uses of I until we find a
-/// memory use. If we find an obviously non-foldable instruction, return true.
-/// Add the ultimately found memory instructions to MemoryUses.
-static bool FindAllMemoryUses(Instruction *I,
- SmallVectorImpl<std::pair<Instruction*,unsigned> > &MemoryUses,
- SmallPtrSet<Instruction*, 16> &ConsideredInsts,
- const TargetLowering &TLI) {
- // If we already considered this instruction, we're done.
- if (!ConsideredInsts.insert(I))
- return false;
-
- // If this is an obviously unfoldable instruction, bail out.
- if (!MightBeFoldableInst(I))
- return true;
-
- // Loop over all the uses, recursively processing them.
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
- UI != E; ++UI) {
- User *U = *UI;
-
- if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
- MemoryUses.push_back(std::make_pair(LI, UI.getOperandNo()));
- continue;
- }
-
- if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
- unsigned opNo = UI.getOperandNo();
- if (opNo == 0) return true; // Storing addr, not into addr.
- MemoryUses.push_back(std::make_pair(SI, opNo));
- continue;
- }
-
- if (CallInst *CI = dyn_cast<CallInst>(U)) {
- InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue());
- if (!IA) return true;
-
- // If this is a memory operand, we're cool, otherwise bail out.
- if (!IsOperandAMemoryOperand(CI, IA, I, TLI))
- return true;
- continue;
- }
-
- if (FindAllMemoryUses(cast<Instruction>(U), MemoryUses, ConsideredInsts,
- TLI))
- return true;
- }
-
- return false;
-}
-
-/// ValueAlreadyLiveAtInst - Retrn true if Val is already known to be live at
-/// the use site that we're folding it into. If so, there is no cost to
-/// include it in the addressing mode. KnownLive1 and KnownLive2 are two values
-/// that we know are live at the instruction already.
-bool AddressingModeMatcher::ValueAlreadyLiveAtInst(Value *Val,Value *KnownLive1,
- Value *KnownLive2) {
- // If Val is either of the known-live values, we know it is live!
- if (Val == 0 || Val == KnownLive1 || Val == KnownLive2)
- return true;
-
- // All values other than instructions and arguments (e.g. constants) are live.
- if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true;
-
- // If Val is a constant sized alloca in the entry block, it is live, this is
- // true because it is just a reference to the stack/frame pointer, which is
- // live for the whole function.
- if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
- if (AI->isStaticAlloca())
- return true;
-
- // Check to see if this value is already used in the memory instruction's
- // block. If so, it's already live into the block at the very least, so we
- // can reasonably fold it.
- return Val->isUsedInBasicBlock(MemoryInst->getParent());
-}
-
-/// IsProfitableToFoldIntoAddressingMode - It is possible for the addressing
-/// mode of the machine to fold the specified instruction into a load or store
-/// that ultimately uses it. However, the specified instruction has multiple
-/// uses. Given this, it may actually increase register pressure to fold it
-/// into the load. For example, consider this code:
-///
-/// X = ...
-/// Y = X+1
-/// use(Y) -> nonload/store
-/// Z = Y+1
-/// load Z
-///
-/// In this case, Y has multiple uses, and can be folded into the load of Z
-/// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to
-/// be live at the use(Y) line. If we don't fold Y into load Z, we use one
-/// fewer register. Since Y can't be folded into "use(Y)" we don't increase the
-/// number of computations either.
-///
-/// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If
-/// X was live across 'load Z' for other reasons, we actually *would* want to
-/// fold the addressing mode in the Z case. This would make Y die earlier.
-bool AddressingModeMatcher::
-IsProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore,
- ExtAddrMode &AMAfter) {
- if (IgnoreProfitability) return true;
-
- // AMBefore is the addressing mode before this instruction was folded into it,
- // and AMAfter is the addressing mode after the instruction was folded. Get
- // the set of registers referenced by AMAfter and subtract out those
- // referenced by AMBefore: this is the set of values which folding in this
- // address extends the lifetime of.
- //
- // Note that there are only two potential values being referenced here,
- // BaseReg and ScaleReg (global addresses are always available, as are any
- // folded immediates).
- Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;
-
- // If the BaseReg or ScaledReg was referenced by the previous addrmode, their
- // lifetime wasn't extended by adding this instruction.
- if (ValueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
- BaseReg = 0;
- if (ValueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
- ScaledReg = 0;
-
- // If folding this instruction (and it's subexprs) didn't extend any live
- // ranges, we're ok with it.
- if (BaseReg == 0 && ScaledReg == 0)
- return true;
-
- // If all uses of this instruction are ultimately load/store/inlineasm's,
- // check to see if their addressing modes will include this instruction. If
- // so, we can fold it into all uses, so it doesn't matter if it has multiple
- // uses.
- SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
- SmallPtrSet<Instruction*, 16> ConsideredInsts;
- if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI))
- return false; // Has a non-memory, non-foldable use!
-
- // Now that we know that all uses of this instruction are part of a chain of
- // computation involving only operations that could theoretically be folded
- // into a memory use, loop over each of these uses and see if they could
- // *actually* fold the instruction.
- SmallVector<Instruction*, 32> MatchedAddrModeInsts;
- for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) {
- Instruction *User = MemoryUses[i].first;
- unsigned OpNo = MemoryUses[i].second;
-
- // Get the access type of this use. If the use isn't a pointer, we don't
- // know what it accesses.
- Value *Address = User->getOperand(OpNo);
- if (!Address->getType()->isPointerTy())
- return false;
- Type *AddressAccessTy = Address->getType()->getPointerElementType();
-
- // Do a match against the root of this address, ignoring profitability. This
- // will tell us if the addressing mode for the memory operation will
- // *actually* cover the shared instruction.
- ExtAddrMode Result;
- TypePromotionTransaction::ConstRestorationPt LastKnownGood =
- TPT.getRestorationPoint();
- AddressingModeMatcher Matcher(MatchedAddrModeInsts, TLI, AddressAccessTy,
- MemoryInst, Result, InsertedTruncs,
- PromotedInsts, TPT);
- Matcher.IgnoreProfitability = true;
- bool Success = Matcher.MatchAddr(Address, 0);
- (void)Success; assert(Success && "Couldn't select *anything*?");
-
- // The match was to check the profitability, the changes made are not
- // part of the original matcher. Therefore, they should be dropped
- // otherwise the original matcher will not present the right state.
- TPT.rollback(LastKnownGood);
-
- // If the match didn't cover I, then it won't be shared by it.
- if (std::find(MatchedAddrModeInsts.begin(), MatchedAddrModeInsts.end(),
- I) == MatchedAddrModeInsts.end())
- return false;
-
- MatchedAddrModeInsts.clear();
- }
-
- return true;
-}
-
-} // end anonymous namespace
-
-/// IsNonLocalValue - Return true if the specified values are defined in a
-/// different basic block than BB.
-static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
- if (Instruction *I = dyn_cast<Instruction>(V))
- return I->getParent() != BB;
- return false;
-}
-
-/// OptimizeMemoryInst - Load and Store Instructions often have
-/// addressing modes that can do significant amounts of computation. As such,
-/// instruction selection will try to get the load or store to do as much
-/// computation as possible for the program. The problem is that isel can only
-/// see within a single block. As such, we sink as much legal addressing mode
-/// stuff into the block as possible.
-///
-/// This method is used to optimize both load/store and inline asms with memory
-/// operands.
-bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
- Type *AccessTy) {
- Value *Repl = Addr;
-
- // Try to collapse single-value PHI nodes. This is necessary to undo
- // unprofitable PRE transformations.
- SmallVector<Value*, 8> worklist;
- SmallPtrSet<Value*, 16> Visited;
- worklist.push_back(Addr);
-
- // Use a worklist to iteratively look through PHI nodes, and ensure that
- // the addressing mode obtained from the non-PHI roots of the graph
- // are equivalent.
- Value *Consensus = 0;
- unsigned NumUsesConsensus = 0;
- bool IsNumUsesConsensusValid = false;
- SmallVector<Instruction*, 16> AddrModeInsts;
- ExtAddrMode AddrMode;
- TypePromotionTransaction TPT;
- TypePromotionTransaction::ConstRestorationPt LastKnownGood =
- TPT.getRestorationPoint();
- while (!worklist.empty()) {
- Value *V = worklist.back();
- worklist.pop_back();
-
- // Break use-def graph loops.
- if (!Visited.insert(V)) {
- Consensus = 0;
- break;
- }
-
- // For a PHI node, push all of its incoming values.
- if (PHINode *P = dyn_cast<PHINode>(V)) {
- for (unsigned i = 0, e = P->getNumIncomingValues(); i != e; ++i)
- worklist.push_back(P->getIncomingValue(i));
- continue;
- }
-
- // For non-PHIs, determine the addressing mode being computed.
- SmallVector<Instruction*, 16> NewAddrModeInsts;
- ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
- V, AccessTy, MemoryInst, NewAddrModeInsts, *TLI, InsertedTruncsSet,
- PromotedInsts, TPT);
-
- // This check is broken into two cases with very similar code to avoid using
- // getNumUses() as much as possible. Some values have a lot of uses, so
- // calling getNumUses() unconditionally caused a significant compile-time
- // regression.
- if (!Consensus) {
- Consensus = V;
- AddrMode = NewAddrMode;
- AddrModeInsts = NewAddrModeInsts;
- continue;
- } else if (NewAddrMode == AddrMode) {
- if (!IsNumUsesConsensusValid) {
- NumUsesConsensus = Consensus->getNumUses();
- IsNumUsesConsensusValid = true;
- }
-
- // Ensure that the obtained addressing mode is equivalent to that obtained
- // for all other roots of the PHI traversal. Also, when choosing one
- // such root as representative, select the one with the most uses in order
- // to keep the cost modeling heuristics in AddressingModeMatcher
- // applicable.
- unsigned NumUses = V->getNumUses();
- if (NumUses > NumUsesConsensus) {
- Consensus = V;
- NumUsesConsensus = NumUses;
- AddrModeInsts = NewAddrModeInsts;
- }
- continue;
- }
-
- Consensus = 0;
- break;
- }
-
- // If the addressing mode couldn't be determined, or if multiple different
- // ones were determined, bail out now.
- if (!Consensus) {
- TPT.rollback(LastKnownGood);
- return false;
- }
- TPT.commit();
-
- // Check to see if any of the instructions supersumed by this addr mode are
- // non-local to I's BB.
- bool AnyNonLocal = false;
- for (unsigned i = 0, e = AddrModeInsts.size(); i != e; ++i) {
- if (IsNonLocalValue(AddrModeInsts[i], MemoryInst->getParent())) {
- AnyNonLocal = true;
- break;
- }
- }
-
- // If all the instructions matched are already in this BB, don't do anything.
- if (!AnyNonLocal) {
- DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrMode << "\n");
- return false;
- }
-
- // Insert this computation right after this user. Since our caller is
- // scanning from the top of the BB to the bottom, reuse of the expr are
- // guaranteed to happen later.
- IRBuilder<> Builder(MemoryInst);
-
- // Now that we determined the addressing expression we want to use and know
- // that we have to sink it into this block. Check to see if we have already
- // done this for some other load/store instr in this block. If so, reuse the
- // computation.
- 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->getDataLayout()->getIntPtrType(Addr->getType());
- Value *Result = 0;
-
- // Start with the base register. Do this first so that subsequent address
- // matching finds it last, which will prevent it from trying to match it
- // as the scaled value in case it happens to be a mul. That would be
- // problematic if we've sunk a different mul for the scale, because then
- // we'd end up sinking both muls.
- 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, /*isSigned=*/true, "sunkaddr");
- Result = V;
- }
-
- // Add the scale value.
- if (AddrMode.Scale) {
- Value *V = AddrMode.ScaledReg;
- if (V->getType() == IntPtrTy) {
- // done.
- } 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;
- }
-
- // Add in the BaseGV if present.
- if (AddrMode.BaseGV) {
- Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
- if (Result)
- Result = Builder.CreateAdd(Result, V, "sunkaddr");
- else
- Result = V;
- }
-
- // Add in the Base Offset if present.
- 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 we have no uses, recursively delete the value and all dead instructions
- // using it.
- if (Repl->use_empty()) {
- // This can cause recursive deletion, which can invalidate our iterator.
- // Use a WeakVH to hold onto it in case this happens.
- WeakVH IterHandle(CurInstIterator);
- BasicBlock *BB = CurInstIterator->getParent();
-
- RecursivelyDeleteTriviallyDeadInstructions(Repl, TLInfo);
-
- if (IterHandle != CurInstIterator) {
- // If the iterator instruction was recursively deleted, start over at the
- // start of the block.
- CurInstIterator = BB->begin();
- SunkAddrs.clear();
- }
- }
- ++NumMemoryInsts;
- return true;
-}
-
-/// OptimizeInlineAsmInst - If there are any memory operands, use
-/// OptimizeMemoryInst to sink their address computing into the block when
-/// possible / profitable.
-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];
-
- // Compute the constraint code and ConstraintType to use.
- 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;
-}
-
-/// 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.
-///
-bool CodeGenPrepare::MoveExtToFormExtLoad(Instruction *I) {
- // Look for a load being extended.
- LoadInst *LI = dyn_cast<LoadInst>(I->getOperand(0));
- if (!LI) return false;
-
- // If they're already in the same block, there's nothing to do.
- if (LI->getParent() == I->getParent())
- return false;
-
- // If the load has other users and the truncate is not free, this probably
- // isn't worthwhile.
- if (!LI->hasOneUse() &&
- TLI && (TLI->isTypeLegal(TLI->getValueType(LI->getType())) ||
- !TLI->isTypeLegal(TLI->getValueType(I->getType()))) &&
- !TLI->isTruncateFree(I->getType(), LI->getType()))
- return false;
-
- // Check whether the target supports casts folded into loads.
- 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;
-
- // Move the extend into the same block as the load, so that SelectionDAG
- // can fold it.
- I->removeFromParent();
- I->insertAfter(LI);
- ++NumExtsMoved;
- return true;
-}
-
-bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
- BasicBlock *DefBB = I->getParent();
-
- // If the result of a {s|z}ext and its source are both live out, rewrite all
- // other uses of the source with result of extension.
- Value *Src = I->getOperand(0);
- if (Src->hasOneUse())
- return false;
-
- // Only do this xform if truncating is free.
- if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
- return false;
-
- // Only safe to perform the optimization if the source is also defined in
- // this block.
- 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);
-
- // Figure out which BB this ext is used in.
- BasicBlock *UserBB = User->getParent();
- if (UserBB == DefBB) continue;
- DefIsLiveOut = true;
- break;
- }
- if (!DefIsLiveOut)
- return false;
-
- // Make sure none of the uses are PHI nodes.
- 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;
- // Be conservative. We don't want this xform to end up introducing
- // reloads just before load / store instructions.
- if (isa<PHINode>(User) || isa<LoadInst>(User) || isa<StoreInst>(User))
- return false;
- }
-
- // InsertedTruncs - Only insert one trunc in each block once.
- 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);
-
- // Figure out which BB this ext is used in.
- BasicBlock *UserBB = User->getParent();
- if (UserBB == DefBB) continue;
-
- // Both src and def are live in this block. Rewrite the use.
- Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
-
- if (!InsertedTrunc) {
- BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
- InsertedTrunc = new TruncInst(I, Src->getType(), "", InsertPt);
- InsertedTruncsSet.insert(InsertedTrunc);
- }
-
- // Replace a use of the {s|z}ext source with a use of the result.
- TheUse = InsertedTrunc;
- ++NumExtUses;
- MadeChange = true;
- }
-
- return MadeChange;
-}
-
-/// isFormingBranchFromSelectProfitable - Returns true if a SelectInst should be
-/// turned into an explicit branch.
-static bool isFormingBranchFromSelectProfitable(SelectInst *SI) {
- // FIXME: This should use the same heuristics as IfConversion to determine
- // whether a select is better represented as a branch. This requires that
- // branch probability metadata is preserved for the select, which is not the
- // case currently.
-
- CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
-
- // If the branch is predicted right, an out of order CPU can avoid blocking on
- // the compare. Emit cmovs on compares with a memory operand as branches to
- // avoid stalls on the load from memory. If the compare has more than one use
- // there's probably another cmov or setcc around so it's not worth emitting a
- // branch.
- if (!Cmp)
- return false;
-
- Value *CmpOp0 = Cmp->getOperand(0);
- Value *CmpOp1 = Cmp->getOperand(1);
-
- // We check that the memory operand has one use to avoid uses of the loaded
- // value directly after the compare, making branches unprofitable.
- return Cmp->hasOneUse() &&
- ((isa<LoadInst>(CmpOp0) && CmpOp0->hasOneUse()) ||
- (isa<LoadInst>(CmpOp1) && CmpOp1->hasOneUse()));
-}
-
-
-/// If we have a SelectInst that will likely profit from branch prediction,
-/// turn it into a branch.
-bool CodeGenPrepare::OptimizeSelectInst(SelectInst *SI) {
- bool VectorCond = !SI->getCondition()->getType()->isIntegerTy(1);
-
- // Can we convert the 'select' to CF ?
- if (DisableSelectToBranch || OptSize || !TLI || VectorCond)
- return false;
-
- TargetLowering::SelectSupportKind SelectKind;
- if (VectorCond)
- SelectKind = TargetLowering::VectorMaskSelect;
- else if (SI->getType()->isVectorTy())
- SelectKind = TargetLowering::ScalarCondVectorVal;
- else
- SelectKind = TargetLowering::ScalarValSelect;
-
- // Do we have efficient codegen support for this kind of 'selects' ?
- if (TLI->isSelectSupported(SelectKind)) {
- // We have efficient codegen support for the select instruction.
- // Check if it is profitable to keep this 'select'.
- if (!TLI->isPredictableSelectExpensive() ||
- !isFormingBranchFromSelectProfitable(SI))
- return false;
- }
-
- ModifiedDT = true;
-
- // First, we split the block containing the select into 2 blocks.
- BasicBlock *StartBlock = SI->getParent();
- BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(SI));
- BasicBlock *NextBlock = StartBlock->splitBasicBlock(SplitPt, "select.end");
-
- // Create a new block serving as the landing pad for the branch.
- BasicBlock *SmallBlock = BasicBlock::Create(SI->getContext(), "select.mid",
- NextBlock->getParent(), NextBlock);
-
- // Move the unconditional branch from the block with the select in it into our
- // landing pad block.
- StartBlock->getTerminator()->eraseFromParent();
- BranchInst::Create(NextBlock, SmallBlock);
-
- // Insert the real conditional branch based on the original condition.
- BranchInst::Create(NextBlock, SmallBlock, SI->getCondition(), SI);
-
- // The select itself is replaced with a PHI Node.
- PHINode *PN = PHINode::Create(SI->getType(), 2, "", NextBlock->begin());
- PN->takeName(SI);
- PN->addIncoming(SI->getTrueValue(), StartBlock);
- PN->addIncoming(SI->getFalseValue(), SmallBlock);
- SI->replaceAllUsesWith(PN);
- SI->eraseFromParent();
-
- // Instruct OptimizeBlock to skip to the next block.
- CurInstIterator = StartBlock->end();
- ++NumSelectsExpanded;
- return true;
-}
-
-
-bool isBroadcastShuffle(ShuffleVectorInst *SVI) {
- SmallVector<int, 16> Mask(SVI->getShuffleMask());
- int SplatElem = -1;
- for (unsigned i = 0; i < Mask.size(); ++i) {
- if (SplatElem != -1 && Mask[i] != -1 && Mask[i] != SplatElem)
- return false;
- SplatElem = Mask[i];
- }
-
- return true;
-}
-
-/// Some targets have expensive vector shifts if the lanes aren't all the same
-/// (e.g. x86 only introduced "vpsllvd" and friends with AVX2). In these cases
-/// it's often worth sinking a shufflevector splat down to its use so that
-/// codegen can spot all lanes are identical.
-bool CodeGenPrepare::OptimizeShuffleVectorInst(ShuffleVectorInst *SVI) {
- BasicBlock *DefBB = SVI->getParent();
-
- // Only do this xform if variable vector shifts are particularly expensive.
- if (!TLI || !TLI->isVectorShiftByScalarCheap(SVI->getType()))
- return false;
-
- // We only expect better codegen by sinking a shuffle if we can recognise a
- // constant splat.
- if (!isBroadcastShuffle(SVI))
- return false;
-
- // InsertedShuffles - Only insert a shuffle in each block once.
- DenseMap<BasicBlock*, Instruction*> InsertedShuffles;
-
- bool MadeChange = false;
- for (Value::use_iterator UI = SVI->use_begin(), E = SVI->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
-
- // Figure out which BB this ext is used in.
- BasicBlock *UserBB = User->getParent();
- if (UserBB == DefBB) continue;
-
- // For now only apply this when the splat is used by a shift instruction.
- if (!User->isShift()) continue;
-
- // Everything checks out, sink the shuffle if the user's block doesn't
- // already have a copy.
- Instruction *&InsertedShuffle = InsertedShuffles[UserBB];
-
- if (!InsertedShuffle) {
- BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
- InsertedShuffle = new ShuffleVectorInst(SVI->getOperand(0),
- SVI->getOperand(1),
- SVI->getOperand(2), "", InsertPt);
- }
-
- User->replaceUsesOfWith(SVI, InsertedShuffle);
- MadeChange = true;
- }
-
- // If we removed all uses, nuke the shuffle.
- if (SVI->use_empty()) {
- SVI->eraseFromParent();
- MadeChange = true;
- }
-
- return MadeChange;
-}
-
-bool CodeGenPrepare::OptimizeInst(Instruction *I) {
- 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
- // trivial PHI, go ahead and zap it here.
- if (Value *V = SimplifyInstruction(P, TLI ? TLI->getDataLayout() : 0,
- TLInfo, DT)) {
- P->replaceAllUsesWith(V);
- P->eraseFromParent();
- ++NumPHIsElim;
- return true;
- }
- return false;
- }
-
- if (CastInst *CI = dyn_cast<CastInst>(I)) {
- // If the source of the cast is a constant, then this should have
- // already been constant folded. The only reason NOT to constant fold
- // it is if something (e.g. LSR) was careful to place the constant
- // evaluation in a block other than then one that uses it (e.g. to hoist
- // the address of globals out of a loop). If this is the case, we don't
- // want to forward-subst the cast.
- 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))
- if (!TLI || !TLI->hasMultipleConditionRegisters())
- 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()) {
- /// The GEP operand must be a pointer, so must its result -> BitCast
- 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 (SelectInst *SI = dyn_cast<SelectInst>(I))
- return OptimizeSelectInst(SI);
-
- if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I))
- return OptimizeShuffleVectorInst(SVI);
-
- 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) {
- SunkAddrs.clear();
- bool MadeChange = false;
-
- CurInstIterator = BB.begin();
- while (CurInstIterator != BB.end())
- MadeChange |= OptimizeInst(CurInstIterator++);
-
- MadeChange |= DupRetToEnableTailCallOpts(&BB);
-
- return MadeChange;
-}
-
-// llvm.dbg.value is far away from the value then iSel may not be able
-// handle it properly. iSel will drop llvm.dbg.value if it can not
-// 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) {
- 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;
-}
void llvm::initializeScalarOpts(PassRegistry &Registry) {
initializeADCEPass(Registry);
initializeSampleProfileLoaderPass(Registry);
- initializeCodeGenPreparePass(Registry);
initializeConstantHoistingPass(Registry);
initializeConstantPropagationPass(Registry);
initializeCorrelatedValuePropagationPass(Registry);
set(LLVM_LINK_COMPONENTS
Analysis
BitWriter
+ CodeGen
Core
IPA
IPO
type = Tool
name = bugpoint
parent = Tools
-required_libraries = AsmParser BitReader BitWriter IRReader IPO Instrumentation Linker Scalar ObjCARC
+required_libraries = AsmParser BitReader BitWriter CodeGen IRReader IPO Instrumentation Linker Scalar ObjCARC
LEVEL := ../..
TOOLNAME := bugpoint
LINK_COMPONENTS := asmparser instrumentation scalaropts ipo linker bitreader \
- bitwriter irreader vectorize objcarcopts
+ bitwriter irreader vectorize objcarcopts codegen
# Support plugins.
NO_DEAD_STRIP := 1
${LLVM_TARGETS_TO_BUILD}
Analysis
BitWriter
+ CodeGen
Core
IPA
IPO
type = Tool
name = opt
parent = Tools
-required_libraries = AsmParser BitReader BitWriter IRReader IPO Instrumentation Scalar ObjCARC all-targets
+required_libraries = AsmParser BitReader BitWriter CodeGen IRReader IPO Instrumentation Scalar ObjCARC all-targets
LEVEL := ../..
TOOLNAME := opt
-LINK_COMPONENTS := bitreader bitwriter asmparser irreader instrumentation scalaropts objcarcopts ipo vectorize all-targets
+LINK_COMPONENTS := bitreader bitwriter asmparser irreader instrumentation scalaropts objcarcopts ipo vectorize all-targets codegen
# Support plugins.
NO_DEAD_STRIP := 1
#include "llvm/Analysis/RegionPass.h"
#include "llvm/Bitcode/BitcodeWriterPass.h"
#include "llvm/CodeGen/CommandFlags.h"
+#include "llvm/InitializePasses.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/IRPrintingPasses.h"
#include "llvm/IR/LLVMContext.h"
initializeInstCombine(Registry);
initializeInstrumentation(Registry);
initializeTarget(Registry);
+ // For codegen passes, only passes that do IR to IR transformation are
+ // supported. For now, just add CodeGenPrepare.
+ initializeCodeGenPreparePass(Registry);
cl::ParseCommandLineOptions(argc, argv,
"llvm .bc -> .bc modular optimizer and analysis printer\n");
projects / oota-llvm.git / commitdiff