#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/PatternMatch.h"
+#include "llvm/IR/Statepoint.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/IR/ValueMap.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/Transforms/Utils/BypassSlowDivision.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
using namespace llvm;
using namespace llvm::PatternMatch;
"disable-cgp-branch-opts", cl::Hidden, cl::init(false),
cl::desc("Disable branch optimizations in CodeGenPrepare"));
+static cl::opt<bool>
+ DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false),
+ cl::desc("Disable GC optimizations in CodeGenPrepare"));
+
static cl::opt<bool> DisableSelectToBranch(
"disable-cgp-select2branch", cl::Hidden, cl::init(false),
cl::desc("Disable select to branch conversion."));
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addPreserved<DominatorTreeWrapperPass>();
- AU.addRequired<TargetLibraryInfo>();
- AU.addRequired<TargetTransformInfo>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ AU.addRequired<TargetTransformInfoWrapperPass>();
}
private:
const SmallVectorImpl<Instruction *> &Exts,
unsigned CreatedInst);
bool splitBranchCondition(Function &F);
+ bool simplifyOffsetableRelocate(Instruction &I);
};
}
ModifiedDT = false;
if (TM)
- TLI = TM->getSubtargetImpl()->getTargetLowering();
- TLInfo = &getAnalysis<TargetLibraryInfo>();
- TTI = &getAnalysis<TargetTransformInfo>();
+ TLI = TM->getSubtargetImpl(F)->getTargetLowering();
+ TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+ TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
DominatorTreeWrapperPass *DTWP =
getAnalysisIfAvailable<DominatorTreeWrapperPass>();
DT = DTWP ? &DTWP->getDomTree() : nullptr;
- OptSize = F.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
- Attribute::OptimizeForSize);
+ OptSize = F.hasFnAttribute(Attribute::OptimizeForSize);
/// This optimization identifies DIV instructions that can be
/// profitably bypassed and carried out with a shorter, faster divide.
BasicBlock *BB = I++;
bool ModifiedDTOnIteration = false;
MadeChange |= OptimizeBlock(*BB, ModifiedDTOnIteration);
-
+
// Restart BB iteration if the dominator tree of the Function was changed
ModifiedDT |= ModifiedDTOnIteration;
if (ModifiedDTOnIteration)
if (!DisableBranchOpts) {
MadeChange = false;
SmallPtrSet<BasicBlock*, 8> WorkList;
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
- SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
- MadeChange |= ConstantFoldTerminator(BB, true);
+ for (BasicBlock &BB : F) {
+ SmallVector<BasicBlock *, 2> Successors(succ_begin(&BB), succ_end(&BB));
+ MadeChange |= ConstantFoldTerminator(&BB, true);
if (!MadeChange) continue;
for (SmallVectorImpl<BasicBlock*>::iterator
EverMadeChange |= MadeChange;
}
+ if (!DisableGCOpts) {
+ SmallVector<Instruction *, 2> Statepoints;
+ for (BasicBlock &BB : F)
+ for (Instruction &I : BB)
+ if (isStatepoint(I))
+ Statepoints.push_back(&I);
+ for (auto &I : Statepoints)
+ EverMadeChange |= simplifyOffsetableRelocate(*I);
+ }
+
if (ModifiedDT && DT)
DT->recalculate(F);
// Remember if SinglePred was the entry block of the function.
// If so, we will need to move BB back to the entry position.
bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
- MergeBasicBlockIntoOnlyPred(BB, this);
+ MergeBasicBlockIntoOnlyPred(BB, DT);
if (isEntry && BB != &BB->getParent()->getEntryBlock())
BB->moveBefore(&BB->getParent()->getEntryBlock());
// Remember if SinglePred was the entry block of the function. If so, we
// will need to move BB back to the entry position.
bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
- MergeBasicBlockIntoOnlyPred(DestBB, this);
+ MergeBasicBlockIntoOnlyPred(DestBB, DT);
if (isEntry && BB != &BB->getParent()->getEntryBlock())
BB->moveBefore(&BB->getParent()->getEntryBlock());
DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
}
+// Computes a map of base pointer relocation instructions to corresponding
+// derived pointer relocation instructions given a vector of all relocate calls
+static void computeBaseDerivedRelocateMap(
+ const SmallVectorImpl<User *> &AllRelocateCalls,
+ DenseMap<IntrinsicInst *, SmallVector<IntrinsicInst *, 2>> &
+ RelocateInstMap) {
+ // Collect information in two maps: one primarily for locating the base object
+ // while filling the second map; the second map is the final structure holding
+ // a mapping between Base and corresponding Derived relocate calls
+ DenseMap<std::pair<unsigned, unsigned>, IntrinsicInst *> RelocateIdxMap;
+ for (auto &U : AllRelocateCalls) {
+ GCRelocateOperands ThisRelocate(U);
+ IntrinsicInst *I = cast<IntrinsicInst>(U);
+ auto K = std::make_pair(ThisRelocate.basePtrIndex(),
+ ThisRelocate.derivedPtrIndex());
+ RelocateIdxMap.insert(std::make_pair(K, I));
+ }
+ for (auto &Item : RelocateIdxMap) {
+ std::pair<unsigned, unsigned> Key = Item.first;
+ if (Key.first == Key.second)
+ // Base relocation: nothing to insert
+ continue;
+
+ IntrinsicInst *I = Item.second;
+ auto BaseKey = std::make_pair(Key.first, Key.first);
+
+ // We're iterating over RelocateIdxMap so we cannot modify it.
+ auto MaybeBase = RelocateIdxMap.find(BaseKey);
+ if (MaybeBase == RelocateIdxMap.end())
+ // TODO: We might want to insert a new base object relocate and gep off
+ // that, if there are enough derived object relocates.
+ continue;
+
+ RelocateInstMap[MaybeBase->second].push_back(I);
+ }
+}
+
+// Accepts a GEP and extracts the operands into a vector provided they're all
+// small integer constants
+static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
+ SmallVectorImpl<Value *> &OffsetV) {
+ for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
+ // Only accept small constant integer operands
+ auto Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
+ if (!Op || Op->getZExtValue() > 20)
+ return false;
+ }
+
+ for (unsigned i = 1; i < GEP->getNumOperands(); i++)
+ OffsetV.push_back(GEP->getOperand(i));
+ return true;
+}
+
+// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
+// replace, computes a replacement, and affects it.
+static bool
+simplifyRelocatesOffABase(IntrinsicInst *RelocatedBase,
+ const SmallVectorImpl<IntrinsicInst *> &Targets) {
+ bool MadeChange = false;
+ for (auto &ToReplace : Targets) {
+ GCRelocateOperands MasterRelocate(RelocatedBase);
+ GCRelocateOperands ThisRelocate(ToReplace);
+
+ assert(ThisRelocate.basePtrIndex() == MasterRelocate.basePtrIndex() &&
+ "Not relocating a derived object of the original base object");
+ if (ThisRelocate.basePtrIndex() == ThisRelocate.derivedPtrIndex()) {
+ // A duplicate relocate call. TODO: coalesce duplicates.
+ continue;
+ }
+
+ Value *Base = ThisRelocate.basePtr();
+ auto Derived = dyn_cast<GetElementPtrInst>(ThisRelocate.derivedPtr());
+ if (!Derived || Derived->getPointerOperand() != Base)
+ continue;
+
+ SmallVector<Value *, 2> OffsetV;
+ if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
+ continue;
+
+ // Create a Builder and replace the target callsite with a gep
+ IRBuilder<> Builder(ToReplace);
+ Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
+ Value *Replacement =
+ Builder.CreateGEP(RelocatedBase, makeArrayRef(OffsetV));
+ Instruction *ReplacementInst = cast<Instruction>(Replacement);
+ ReplacementInst->removeFromParent();
+ ReplacementInst->insertAfter(RelocatedBase);
+ Replacement->takeName(ToReplace);
+ ToReplace->replaceAllUsesWith(Replacement);
+ ToReplace->eraseFromParent();
+
+ MadeChange = true;
+ }
+ return MadeChange;
+}
+
+// Turns this:
+//
+// %base = ...
+// %ptr = gep %base + 15
+// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
+// %base' = relocate(%tok, i32 4, i32 4)
+// %ptr' = relocate(%tok, i32 4, i32 5)
+// %val = load %ptr'
+//
+// into this:
+//
+// %base = ...
+// %ptr = gep %base + 15
+// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
+// %base' = gc.relocate(%tok, i32 4, i32 4)
+// %ptr' = gep %base' + 15
+// %val = load %ptr'
+bool CodeGenPrepare::simplifyOffsetableRelocate(Instruction &I) {
+ bool MadeChange = false;
+ SmallVector<User *, 2> AllRelocateCalls;
+
+ for (auto *U : I.users())
+ if (isGCRelocate(dyn_cast<Instruction>(U)))
+ // Collect all the relocate calls associated with a statepoint
+ AllRelocateCalls.push_back(U);
+
+ // We need atleast one base pointer relocation + one derived pointer
+ // relocation to mangle
+ if (AllRelocateCalls.size() < 2)
+ return false;
+
+ // RelocateInstMap is a mapping from the base relocate instruction to the
+ // corresponding derived relocate instructions
+ DenseMap<IntrinsicInst *, SmallVector<IntrinsicInst *, 2>> RelocateInstMap;
+ computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
+ if (RelocateInstMap.empty())
+ return false;
+
+ for (auto &Item : RelocateInstMap)
+ // Item.first is the RelocatedBase to offset against
+ // Item.second is the vector of Targets to replace
+ MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
+ return MadeChange;
+}
+
/// SinkCast - Sink the specified cast instruction into its user blocks
static bool SinkCast(CastInst *CI) {
BasicBlock *DefBB = CI->getParent();
return MadeChange;
}
-namespace {
-class CodeGenPrepareFortifiedLibCalls : public SimplifyFortifiedLibCalls {
-protected:
- void replaceCall(Value *With) override {
- CI->replaceAllUsesWith(With);
- CI->eraseFromParent();
- }
- bool isFoldable(unsigned SizeCIOp, unsigned, bool) const override {
- if (ConstantInt *SizeCI =
- dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp)))
- return SizeCI->isAllOnesValue();
- return false;
- }
-};
-} // end anonymous namespace
-
// ScalarizeMaskedLoad() translates masked load intrinsic, like
// <16 x i32 > @llvm.masked.load( <16 x i32>* %addr, i32 align,
// <16 x i1> %mask, <16 x i32> %passthru)
// Lower all default uses of _chk calls. This is very similar
// to what InstCombineCalls does, but here we are only lowering calls
- // that have the default "don't know" as the objectsize. Anything else
- // should be left alone.
- CodeGenPrepareFortifiedLibCalls Simplifier;
- return Simplifier.fold(CI, TD, TLInfo);
+ // to fortified library functions (e.g. __memcpy_chk) that have the default
+ // "don't know" as the objectsize. Anything else should be left alone.
+ FortifiedLibCallSimplifier Simplifier(TD, TLInfo, true);
+ if (Value *V = Simplifier.optimizeCall(CI)) {
+ CI->replaceAllUsesWith(V);
+ CI->eraseFromParent();
+ return true;
+ }
+ return false;
}
/// DupRetToEnableTailCallOpts - Look for opportunities to duplicate return
/// This encapsulates the logic for matching the target-legal addressing modes.
class AddressingModeMatcher {
SmallVectorImpl<Instruction*> &AddrModeInsts;
+ const TargetMachine &TM;
const TargetLowering &TLI;
/// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
/// always returns true.
bool IgnoreProfitability;
- AddressingModeMatcher(SmallVectorImpl<Instruction*> &AMI,
- const TargetLowering &T, Type *AT,
- Instruction *MI, ExtAddrMode &AM,
- const SetOfInstrs &InsertedTruncs,
+ AddressingModeMatcher(SmallVectorImpl<Instruction *> &AMI,
+ const TargetMachine &TM, Type *AT, Instruction *MI,
+ ExtAddrMode &AM, const SetOfInstrs &InsertedTruncs,
InstrToOrigTy &PromotedInsts,
TypePromotionTransaction &TPT)
- : AddrModeInsts(AMI), TLI(T), AccessTy(AT), MemoryInst(MI), AddrMode(AM),
+ : AddrModeInsts(AMI), TM(TM),
+ TLI(*TM.getSubtargetImpl(*MI->getParent()->getParent())
+ ->getTargetLowering()),
+ AccessTy(AT), MemoryInst(MI), AddrMode(AM),
InsertedTruncs(InsertedTruncs), PromotedInsts(PromotedInsts), TPT(TPT) {
IgnoreProfitability = false;
}
static ExtAddrMode Match(Value *V, Type *AccessTy,
Instruction *MemoryInst,
SmallVectorImpl<Instruction*> &AddrModeInsts,
- const TargetLowering &TLI,
+ const TargetMachine &TM,
const SetOfInstrs &InsertedTruncs,
InstrToOrigTy &PromotedInsts,
TypePromotionTransaction &TPT) {
ExtAddrMode Result;
- bool Success = AddressingModeMatcher(AddrModeInsts, TLI, AccessTy,
+ bool Success = AddressingModeMatcher(AddrModeInsts, TM, AccessTy,
MemoryInst, Result, InsertedTruncs,
PromotedInsts, TPT).MatchAddr(V, 0);
(void)Success; assert(Success && "Couldn't select *anything*?");
/// 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));
+ const TargetMachine &TM) {
+ const Function *F = CI->getParent()->getParent();
+ const TargetLowering *TLI = TM.getSubtargetImpl(*F)->getTargetLowering();
+ const TargetRegisterInfo *TRI = TM.getSubtargetImpl(*F)->getRegisterInfo();
+ TargetLowering::AsmOperandInfoVector TargetConstraints =
+ TLI->ParseConstraints(TRI, 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());
+ 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!
/// 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,
- SmallPtrSetImpl<Instruction*> &ConsideredInsts,
- const TargetLowering &TLI) {
+static bool FindAllMemoryUses(
+ Instruction *I,
+ SmallVectorImpl<std::pair<Instruction *, unsigned>> &MemoryUses,
+ SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetMachine &TM) {
// If we already considered this instruction, we're done.
if (!ConsideredInsts.insert(I).second)
return false;
if (!IA) return true;
// If this is a memory operand, we're cool, otherwise bail out.
- if (!IsOperandAMemoryOperand(CI, IA, I, TLI))
+ if (!IsOperandAMemoryOperand(CI, IA, I, TM))
return true;
continue;
}
- if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI))
+ if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TM))
return true;
}
// uses.
SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
SmallPtrSet<Instruction*, 16> ConsideredInsts;
- if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TLI))
+ if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TM))
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
ExtAddrMode Result;
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
TPT.getRestorationPoint();
- AddressingModeMatcher Matcher(MatchedAddrModeInsts, TLI, AddressAccessTy,
+ AddressingModeMatcher Matcher(MatchedAddrModeInsts, TM, AddressAccessTy,
MemoryInst, Result, InsertedTruncs,
PromotedInsts, TPT);
Matcher.IgnoreProfitability = true;
// For non-PHIs, determine the addressing mode being computed.
SmallVector<Instruction*, 16> NewAddrModeInsts;
ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
- V, AccessTy, MemoryInst, NewAddrModeInsts, *TLI, InsertedTruncsSet,
+ V, AccessTy, MemoryInst, NewAddrModeInsts, *TM, InsertedTruncsSet,
PromotedInsts, TPT);
// This check is broken into two cases with very similar code to avoid using
<< *MemoryInst << "\n");
if (SunkAddr->getType() != Addr->getType())
SunkAddr = Builder.CreateBitCast(SunkAddr, Addr->getType());
- } else if (AddrSinkUsingGEPs || (!AddrSinkUsingGEPs.getNumOccurrences() &&
- TM && TM->getSubtarget<TargetSubtargetInfo>().useAA())) {
+ } else if (AddrSinkUsingGEPs ||
+ (!AddrSinkUsingGEPs.getNumOccurrences() && TM &&
+ TM->getSubtargetImpl(*MemoryInst->getParent()->getParent())
+ ->useAA())) {
// By default, we use the GEP-based method when AA is used later. This
// prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrMode << " for "
bool CodeGenPrepare::OptimizeInlineAsmInst(CallInst *CS) {
bool MadeChange = false;
+ const TargetRegisterInfo *TRI =
+ TM->getSubtargetImpl(*CS->getParent()->getParent())->getRegisterInfo();
TargetLowering::AsmOperandInfoVector
- TargetConstraints = TLI->ParseConstraints(CS);
+ TargetConstraints = TLI->ParseConstraints(TRI, CS);
unsigned ArgNo = 0;
for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
assert(isa<SExtInst>(I) && "Unexpected ext type!");
LType = ISD::SEXTLOAD;
}
- if (TLI && !TLI->isLoadExtLegal(LType, LoadVT)) {
+ if (TLI && !TLI->isLoadExtLegal(LType, VT, LoadVT)) {
I = OldExt;
TPT.rollback(LastKnownGood);
return false;
Transition->setOperand(getTransitionOriginalValueIdx(), ToBePromoted);
}
-// See if we can speculate calls to intrinsic cttz/ctlz.
-//
-// Example:
-// entry:
-// ...
-// %cmp = icmp eq i64 %val, 0
-// br i1 %cmp, label %end.bb, label %then.bb
-//
-// then.bb:
-// %c = tail call i64 @llvm.cttz.i64(i64 %val, i1 true)
-// br label %EndBB
-//
-// end.bb:
-// %cond = phi i64 [ %c, %then.bb ], [ 64, %entry ]
-//
-// ==>
-//
-// entry:
-// ...
-// %c = tail call i64 @llvm.cttz.i64(i64 %val, i1 false)
-//
-static bool OptimizeBranchInst(BranchInst *BrInst, const TargetLowering &TLI) {
- assert(BrInst->isConditional() && "Expected a conditional branch!");
- BasicBlock *ThenBB = BrInst->getSuccessor(1);
- BasicBlock *EndBB = BrInst->getSuccessor(0);
-
- // See if ThenBB contains only one instruction (excluding the
- // terminator and DbgInfoIntrinsic calls).
- IntrinsicInst *II = nullptr;
- for (BasicBlock::iterator I = ThenBB->begin(),
- E = std::prev(ThenBB->end()); I != E; ++I) {
- // Skip debug info.
- if (isa<DbgInfoIntrinsic>(I))
- continue;
-
- if (II)
- // Avoid speculating more than one instruction.
- return false;
-
- // See if this is a call to intrinsic cttz/ctlz.
- if (match(cast<Instruction>(I), m_Intrinsic<Intrinsic::cttz>())) {
- // Avoid speculating expensive intrinsic calls.
- if (!TLI.isCheapToSpeculateCttz())
- return false;
- }
- else if (match(cast<Instruction>(I), m_Intrinsic<Intrinsic::ctlz>())) {
- // Avoid speculating expensive intrinsic calls.
- if (!TLI.isCheapToSpeculateCtlz())
- return false;
- } else
- return false;
-
- II = cast<IntrinsicInst>(I);
- }
-
- // Look for PHI nodes with 'II' as the incoming value from 'ThenBB'.
- BasicBlock *EntryBB = BrInst->getParent();
- for (BasicBlock::iterator I = EndBB->begin();
- PHINode *PN = dyn_cast<PHINode>(I); ++I) {
- Value *ThenV = PN->getIncomingValueForBlock(ThenBB);
- Value *OrigV = PN->getIncomingValueForBlock(EntryBB);
-
- if (!OrigV || ThenV != II)
- return false;
-
- if (ConstantInt *CInt = dyn_cast<ConstantInt>(OrigV)) {
- unsigned BitWidth = ThenV->getType()->getIntegerBitWidth();
-
- // Don't try to simplify this phi node if 'ThenV' is a cttz/ctlz
- // intrinsic call, but 'OrigV' is not equal to the 'size-of' in bits
- // of the value in input to the cttz/ctlz.
- if (CInt->getValue() != BitWidth)
- return false;
-
- // Hoist the call to cttz/ctlz from ThenBB into EntryBB.
- EntryBB->getInstList().splice(BrInst, ThenBB->getInstList(),
- ThenBB->begin(), std::prev(ThenBB->end()));
-
- // Update PN setting ThenV as the incoming value from both 'EntryBB'
- // and 'ThenBB'. Eventually, method 'OptimizeInst' will fold this
- // phi node if all the incoming values are the same.
- PN->setIncomingValue(PN->getBasicBlockIndex(EntryBB), ThenV);
- PN->setIncomingValue(PN->getBasicBlockIndex(ThenBB), ThenV);
-
- // Clear the 'undef on zero' flag of the cttz/ctlz intrinsic call.
- if (cast<ConstantInt>(II->getArgOperand(1))->isOne()) {
- Type *Ty = II->getArgOperand(0)->getType();
- Value *Args[] = { II->getArgOperand(0),
- ConstantInt::getFalse(II->getContext()) };
- Module *M = EntryBB->getParent()->getParent();
- Value *IF = Intrinsic::getDeclaration(M, II->getIntrinsicID(), Ty);
- IRBuilder<> Builder(BrInst);
- Instruction *NewI = Builder.CreateCall(IF, Args);
-
- // Replace the old call to cttz/ctlz.
- II->replaceAllUsesWith(NewI);
- II->eraseFromParent();
- }
-
- // Update BrInst condition so that the branch to EndBB is always taken.
- // Later on, method 'ConstantFoldTerminator' will simplify this branch
- // replacing it with a direct branch to 'EndBB'.
- // As a side effect, CodeGenPrepare will attempt to simplify the control
- // flow graph by deleting basic block 'ThenBB' and merging 'EntryBB' into
- // 'EndBB' (calling method 'EliminateFallThrough').
- BrInst->setCondition(ConstantInt::getTrue(BrInst->getContext()));
- return true;
- }
- }
-
- return false;
-}
-
/// Some targets can do store(extractelement) with one instruction.
/// Try to push the extractelement towards the stores when the target
/// has this feature and this is profitable.
if (isa<ExtractElementInst>(I))
return OptimizeExtractElementInst(I);
- if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
- if (TLI && BI->isConditional() && BI->getCondition()->hasOneUse()) {
- // Check if the branch condition compares a value agaist zero.
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) {
- if (ICI->getPredicate() == ICmpInst::ICMP_EQ &&
- match(ICI->getOperand(1), m_Zero())) {
- BasicBlock *ThenBB = BI->getSuccessor(1);
- BasicBlock *EndBB = BI->getSuccessor(0);
-
- // Check if ThenBB is only reachable from this basic block; also,
- // check if EndBB has more than one predecessor.
- if (ThenBB->getSinglePredecessor() &&
- !EndBB->getSinglePredecessor()) {
- TerminatorInst *TI = ThenBB->getTerminator();
-
- if (TI->getNumSuccessors() == 1 && TI->getSuccessor(0) == EndBB &&
- // Try to speculate calls to intrinsic cttz/ctlz from 'ThenBB'.
- OptimizeBranchInst(BI, *TLI)) {
- ModifiedDT = true;
- return true;
- }
- }
- }
- }
- }
- return false;
- }
-
return false;
}
// find a node corresponding to the value.
bool CodeGenPrepare::PlaceDbgValues(Function &F) {
bool MadeChange = false;
- for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
+ for (BasicBlock &BB : F) {
Instruction *PrevNonDbgInst = nullptr;
- for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE;) {
- Instruction *Insn = BI; ++BI;
+ for (BasicBlock::iterator BI = BB.begin(), BE = BB.end(); BI != BE;) {
+ Instruction *Insn = BI++;
DbgValueInst *DVI = dyn_cast<DbgValueInst>(Insn);
// Leave dbg.values that refer to an alloca alone. These
// instrinsics describe the address of a variable (= the alloca)
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