STATISTIC(NumRewrittenCopies, "Number of copies rewritten");
namespace {
+ class ValueTrackerResult;
+
class PeepholeOptimizer : public MachineFunctionPass {
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
}
};
+ /// \brief Helper class to hold a reply for ValueTracker queries. Contains the
+ /// returned sources for a given search and the instructions where the sources
+ /// were tracked from.
+ class ValueTrackerResult {
+ private:
+ /// Track all sources found by one ValueTracker query.
+ SmallVector<TargetInstrInfo::RegSubRegPair, 2> RegSrcs;
+
+ /// Instruction using the sources in 'RegSrcs'.
+ const MachineInstr *Inst;
+
+ public:
+ ValueTrackerResult() : Inst(nullptr) {}
+ ValueTrackerResult(unsigned Reg, unsigned SubReg) : Inst(nullptr) {
+ addSource(Reg, SubReg);
+ }
+
+ bool isValid() const { return getNumSources() > 0; }
+
+ void setInst(const MachineInstr *I) { Inst = I; }
+ const MachineInstr *getInst() const { return Inst; }
+
+ void clear() {
+ RegSrcs.clear();
+ Inst = nullptr;
+ }
+
+ void addSource(unsigned SrcReg, unsigned SrcSubReg) {
+ RegSrcs.push_back(TargetInstrInfo::RegSubRegPair(SrcReg, SrcSubReg));
+ }
+
+ void setSource(int Idx, unsigned SrcReg, unsigned SrcSubReg) {
+ assert(Idx < getNumSources() && "Reg pair source out of index");
+ RegSrcs[Idx] = TargetInstrInfo::RegSubRegPair(SrcReg, SrcSubReg);
+ }
+
+ int getNumSources() const { return RegSrcs.size(); }
+
+ unsigned getSrcReg(int Idx) const {
+ assert(Idx < getNumSources() && "Reg source out of index");
+ return RegSrcs[Idx].Reg;
+ }
+
+ unsigned getSrcSubReg(int Idx) const {
+ assert(Idx < getNumSources() && "SubReg source out of index");
+ return RegSrcs[Idx].SubReg;
+ }
+ };
+
/// \brief Helper class to track the possible sources of a value defined by
/// a (chain of) copy related instructions.
/// Given a definition (instruction and definition index), this class
/// \brief Dispatcher to the right underlying implementation of
/// getNextSource.
- bool getNextSourceImpl(unsigned &SrcReg, unsigned &SrcSubReg);
+ ValueTrackerResult getNextSourceImpl();
/// \brief Specialized version of getNextSource for Copy instructions.
- bool getNextSourceFromCopy(unsigned &SrcReg, unsigned &SrcSubReg);
+ ValueTrackerResult getNextSourceFromCopy();
/// \brief Specialized version of getNextSource for Bitcast instructions.
- bool getNextSourceFromBitcast(unsigned &SrcReg, unsigned &SrcSubReg);
+ ValueTrackerResult getNextSourceFromBitcast();
/// \brief Specialized version of getNextSource for RegSequence
/// instructions.
- bool getNextSourceFromRegSequence(unsigned &SrcReg, unsigned &SrcSubReg);
+ ValueTrackerResult getNextSourceFromRegSequence();
/// \brief Specialized version of getNextSource for InsertSubreg
/// instructions.
- bool getNextSourceFromInsertSubreg(unsigned &SrcReg, unsigned &SrcSubReg);
+ ValueTrackerResult getNextSourceFromInsertSubreg();
/// \brief Specialized version of getNextSource for ExtractSubreg
/// instructions.
- bool getNextSourceFromExtractSubreg(unsigned &SrcReg, unsigned &SrcSubReg);
+ ValueTrackerResult getNextSourceFromExtractSubreg();
/// \brief Specialized version of getNextSource for SubregToReg
/// instructions.
- bool getNextSourceFromSubregToReg(unsigned &SrcReg, unsigned &SrcSubReg);
+ ValueTrackerResult getNextSourceFromSubregToReg();
public:
/// \brief Create a ValueTracker instance for the value defined by \p Reg.
/// \brief Following the use-def chain, get the next available source
/// for the tracked value.
- /// When the returned value is not nullptr, \p SrcReg gives the register
- /// that contain the tracked value.
- /// \note The sub register index returned in \p SrcSubReg must be used
- /// on \p SrcReg to access the actual value.
- /// \return Unless the returned value is nullptr (i.e., no source found),
- /// \p SrcReg gives the register of the next source used in the returned
- /// instruction and \p SrcSubReg the sub-register index to be used on that
- /// source to get the tracked value. When nullptr is returned, no
- /// alternative source has been found.
- const MachineInstr *getNextSource(unsigned &SrcReg, unsigned &SrcSubReg);
+ /// \return A ValueTrackerResult containing the a set of registers
+ /// and sub registers with tracked values. A ValueTrackerResult with
+ /// an empty set of registers means no source was found.
+ ValueTrackerResult getNextSource();
/// \brief Get the last register where the initial value can be found.
/// Initially this is the register of the definition.
// or find a more suitable source.
ValueTracker ValTracker(Reg, DefSubReg, *MRI, !DisableAdvCopyOpt, TII);
do {
- unsigned CopySrcReg, CopySrcSubReg;
- if (!ValTracker.getNextSource(CopySrcReg, CopySrcSubReg))
+ ValueTrackerResult Res = ValTracker.getNextSource();
+ if (!Res.isValid())
break;
- Src = CopySrcReg;
- SrcSubReg = CopySrcSubReg;
+ Src = Res.getSrcReg(0);
+ SrcSubReg = Res.getSrcSubReg(0);
// Do not extend the live-ranges of physical registers as they add
// constraints to the register allocator.
/// \brief Rewrite the current source with \p NewReg and \p NewSubReg
/// if possible.
- /// \return True if the rewritting was possible, false otherwise.
+ /// \return True if the rewriting was possible, false otherwise.
virtual bool RewriteCurrentSource(unsigned NewReg, unsigned NewSubReg) {
if (!CopyLike.isCopy() || CurrentSrcIdx != 1)
return false;
MOSrc.setSubReg(NewSubReg);
return true;
}
+
+ /// \brief Rewrite the current source with \p NewSrcReg and \p NewSecSubReg
+ /// by creating a new COPY instruction. \p DefReg and \p DefSubReg contain the
+ /// definition to be rewritten from the original copylike instruction.
+ /// \return The new COPY if the rewriting was possible, nullptr otherwise.
+ /// This is needed to handle Uncoalescable copies, since they are copy
+ /// like instructions that aren't recognized by the register allocator.
+ virtual MachineInstr *RewriteCurrentSource(unsigned DefReg,
+ unsigned DefSubReg,
+ unsigned NewSrcReg,
+ unsigned NewSrcSubReg) {
+ return nullptr;
+ }
+};
+
+/// \brief Helper class to rewrite uncoalescable copy like instructions
+/// into new COPY (coalescable friendly) instructions.
+class UncoalescableRewriter : public CopyRewriter {
+protected:
+ const TargetInstrInfo &TII;
+ MachineRegisterInfo &MRI;
+ /// The number of defs in the bitcast
+ unsigned NumDefs;
+
+public:
+ UncoalescableRewriter(MachineInstr &MI, const TargetInstrInfo &TII,
+ MachineRegisterInfo &MRI)
+ : CopyRewriter(MI), TII(TII), MRI(MRI) {
+ NumDefs = MI.getDesc().getNumDefs();
+ }
+
+ /// \brief Get the next rewritable def source (TrackReg, TrackSubReg)
+ /// All such sources need to be considered rewritable in order to
+ /// rewrite a uncoalescable copy-like instruction. This method return
+ /// each definition that must be checked if rewritable.
+ ///
+ bool getNextRewritableSource(unsigned &SrcReg, unsigned &SrcSubReg,
+ unsigned &TrackReg,
+ unsigned &TrackSubReg) override {
+ // Find the next non-dead definition and continue from there.
+ if (CurrentSrcIdx == NumDefs)
+ return false;
+
+ while (CopyLike.getOperand(CurrentSrcIdx).isDead()) {
+ ++CurrentSrcIdx;
+ if (CurrentSrcIdx == NumDefs)
+ return false;
+ }
+
+ // What we track are the alternative sources of the definition.
+ const MachineOperand &MODef = CopyLike.getOperand(CurrentSrcIdx);
+ TrackReg = MODef.getReg();
+ TrackSubReg = MODef.getSubReg();
+
+ CurrentSrcIdx++;
+ return true;
+ }
+
+ /// \brief Rewrite the current source with \p NewSrcReg and \p NewSrcSubReg
+ /// by creating a new COPY instruction. \p DefReg and \p DefSubReg contain the
+ /// definition to be rewritten from the original copylike instruction.
+ /// \return The new COPY if the rewriting was possible, nullptr otherwise.
+ MachineInstr *RewriteCurrentSource(unsigned DefReg, unsigned DefSubReg,
+ unsigned NewSrcReg,
+ unsigned NewSrcSubReg) override {
+ assert(!TargetRegisterInfo::isPhysicalRegister(DefReg) &&
+ "We do not rewrite physical registers");
+
+ const TargetRegisterClass *DefRC = MRI.getRegClass(DefReg);
+ unsigned NewVR = MRI.createVirtualRegister(DefRC);
+
+ MachineInstr *NewCopy =
+ BuildMI(*CopyLike.getParent(), &CopyLike, CopyLike.getDebugLoc(),
+ TII.get(TargetOpcode::COPY), NewVR)
+ .addReg(NewSrcReg, 0, NewSrcSubReg);
+
+ NewCopy->getOperand(0).setSubReg(DefSubReg);
+ if (DefSubReg)
+ NewCopy->getOperand(0).setIsUndef();
+
+ MRI.replaceRegWith(DefReg, NewVR);
+ MRI.clearKillFlags(NewVR);
+
+ return NewCopy;
+ }
};
/// \brief Specialized rewriter for INSERT_SUBREG instruction.
/// \return A pointer to a dynamically allocated CopyRewriter or nullptr
/// if no rewriter works for \p MI.
static CopyRewriter *getCopyRewriter(MachineInstr &MI,
- const TargetInstrInfo &TII) {
+ const TargetInstrInfo &TII,
+ MachineRegisterInfo &MRI) {
+ // Handle uncoalescable copy-like instructions.
+ if (MI.isBitcast() || (MI.isRegSequenceLike() || MI.isInsertSubregLike() ||
+ MI.isExtractSubregLike()))
+ return new UncoalescableRewriter(MI, TII, MRI);
+
switch (MI.getOpcode()) {
default:
return nullptr;
bool Changed = false;
// Get the right rewriter for the current copy.
- std::unique_ptr<CopyRewriter> CpyRewriter(getCopyRewriter(*MI, *TII));
+ std::unique_ptr<CopyRewriter> CpyRewriter(getCopyRewriter(*MI, *TII, *MRI));
// If none exists, bails out.
if (!CpyRewriter)
return false;
TrackSubReg)) {
unsigned NewSrc = TrackReg;
unsigned NewSubReg = TrackSubReg;
- // Try to find a more suitable source.
- // If we failed to do so, or get the actual source,
- // move to the next source.
+ // Try to find a more suitable source. If we failed to do so, or get the
+ // actual source, move to the next source.
if (!findNextSource(NewSrc, NewSubReg) || SrcReg == NewSrc)
continue;
// Rewrite source.
SmallVector<
std::pair<TargetInstrInfo::RegSubRegPair, TargetInstrInfo::RegSubRegPair>,
4> RewritePairs;
- for (const MachineOperand &MODef : MI->defs()) {
- if (MODef.isDead())
- // We can ignore those.
- continue;
+ // Get the right rewriter for the current copy.
+ std::unique_ptr<CopyRewriter> CpyRewriter(getCopyRewriter(*MI, *TII, *MRI));
+ // If none exists, bails out.
+ if (!CpyRewriter)
+ return false;
+ // Rewrite each rewritable source by generating new COPYs. This works
+ // differently from optimizeCoalescableCopy since it first makes sure that all
+ // definitions can be rewritten.
+ unsigned SrcReg, SrcSubReg, TrackReg, TrackSubReg;
+ while (CpyRewriter->getNextRewritableSource(SrcReg, SrcSubReg, TrackReg,
+ TrackSubReg)) {
// If a physical register is here, this is probably for a good reason.
// Do not rewrite that.
- if (TargetRegisterInfo::isPhysicalRegister(MODef.getReg()))
+ if (TargetRegisterInfo::isPhysicalRegister(TrackReg))
return false;
// If we do not know how to rewrite this definition, there is no point
// in trying to kill this instruction.
- TargetInstrInfo::RegSubRegPair Def(MODef.getReg(), MODef.getSubReg());
+ TargetInstrInfo::RegSubRegPair Def(TrackReg, TrackSubReg);
TargetInstrInfo::RegSubRegPair Src = Def;
if (!findNextSource(Src.Reg, Src.SubReg))
return false;
+
RewritePairs.push_back(std::make_pair(Def, Src));
}
+
// The change is possible for all defs, do it.
for (const auto &PairDefSrc : RewritePairs) {
const auto &Def = PairDefSrc.first;
const auto &Src = PairDefSrc.second;
+
// Rewrite the "copy" in a way the register coalescer understands.
- assert(!TargetRegisterInfo::isPhysicalRegister(Def.Reg) &&
- "We do not rewrite physical registers");
- const TargetRegisterClass *DefRC = MRI->getRegClass(Def.Reg);
- unsigned NewVR = MRI->createVirtualRegister(DefRC);
- MachineInstr *NewCopy = BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
- TII->get(TargetOpcode::COPY),
- NewVR).addReg(Src.Reg, 0, Src.SubReg);
- NewCopy->getOperand(0).setSubReg(Def.SubReg);
- if (Def.SubReg)
- NewCopy->getOperand(0).setIsUndef();
- LocalMIs.insert(NewCopy);
- MRI->replaceRegWith(Def.Reg, NewVR);
- MRI->clearKillFlags(NewVR);
- // We extended the lifetime of Src.
- // Clear the kill flags to account for that.
+ MachineInstr *NewCopy = CpyRewriter->RewriteCurrentSource(
+ Def.Reg, Def.SubReg, Src.Reg, Src.SubReg);
+ assert(NewCopy && "Should be able to always generate a new copy");
+
+ // We extended the lifetime of Src and clear the kill flags to
+ // account for that.
MRI->clearKillFlags(Src.Reg);
+ LocalMIs.insert(NewCopy);
}
// MI is now dead.
MI->eraseFromParent();
return Changed;
}
-bool ValueTracker::getNextSourceFromCopy(unsigned &SrcReg,
- unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSourceFromCopy() {
assert(Def->isCopy() && "Invalid definition");
// Copy instruction are supposed to be: Def = Src.
// If someone breaks this assumption, bad things will happen everywhere.
if (Def->getOperand(DefIdx).getSubReg() != DefSubReg)
// If we look for a different subreg, it means we want a subreg of src.
// Bails as we do not support composing subreg yet.
- return false;
+ return ValueTrackerResult();
// Otherwise, we want the whole source.
const MachineOperand &Src = Def->getOperand(1);
- SrcReg = Src.getReg();
- SrcSubReg = Src.getSubReg();
- return true;
+ return ValueTrackerResult(Src.getReg(), Src.getSubReg());
}
-bool ValueTracker::getNextSourceFromBitcast(unsigned &SrcReg,
- unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSourceFromBitcast() {
assert(Def->isBitcast() && "Invalid definition");
// Bail if there are effects that a plain copy will not expose.
if (Def->hasUnmodeledSideEffects())
- return false;
+ return ValueTrackerResult();
// Bitcasts with more than one def are not supported.
if (Def->getDesc().getNumDefs() != 1)
- return false;
+ return ValueTrackerResult();
if (Def->getOperand(DefIdx).getSubReg() != DefSubReg)
// If we look for a different subreg, it means we want a subreg of the src.
// Bails as we do not support composing subreg yet.
- return false;
+ return ValueTrackerResult();
unsigned SrcIdx = Def->getNumOperands();
for (unsigned OpIdx = DefIdx + 1, EndOpIdx = SrcIdx; OpIdx != EndOpIdx;
assert(!MO.isDef() && "We should have skipped all the definitions by now");
if (SrcIdx != EndOpIdx)
// Multiple sources?
- return false;
+ return ValueTrackerResult();
SrcIdx = OpIdx;
}
const MachineOperand &Src = Def->getOperand(SrcIdx);
- SrcReg = Src.getReg();
- SrcSubReg = Src.getSubReg();
- return true;
+ return ValueTrackerResult(Src.getReg(), Src.getSubReg());
}
-bool ValueTracker::getNextSourceFromRegSequence(unsigned &SrcReg,
- unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSourceFromRegSequence() {
assert((Def->isRegSequence() || Def->isRegSequenceLike()) &&
"Invalid definition");
// have this case.
// If we can ascertain (or force) that this never happens, we could
// turn that into an assertion.
- return false;
+ return ValueTrackerResult();
if (!TII)
// We could handle the REG_SEQUENCE here, but we do not want to
// duplicate the code from the generic TII.
- return false;
+ return ValueTrackerResult();
SmallVector<TargetInstrInfo::RegSubRegPairAndIdx, 8> RegSeqInputRegs;
if (!TII->getRegSequenceInputs(*Def, DefIdx, RegSeqInputRegs))
- return false;
+ return ValueTrackerResult();
// We are looking at:
// Def = REG_SEQUENCE v0, sub0, v1, sub1, ...
if (RegSeqInput.SubIdx == DefSubReg) {
if (RegSeqInput.SubReg)
// Bails if we have to compose sub registers.
- return false;
+ return ValueTrackerResult();
- SrcReg = RegSeqInput.Reg;
- SrcSubReg = RegSeqInput.SubReg;
- return true;
+ return ValueTrackerResult(RegSeqInput.Reg, RegSeqInput.SubReg);
}
}
// If the subreg we are tracking is super-defined by another subreg,
// we could follow this value. However, this would require to compose
// the subreg and we do not do that for now.
- return false;
+ return ValueTrackerResult();
}
-bool ValueTracker::getNextSourceFromInsertSubreg(unsigned &SrcReg,
- unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSourceFromInsertSubreg() {
assert((Def->isInsertSubreg() || Def->isInsertSubregLike()) &&
"Invalid definition");
// If we are composing subreg, bails out.
// Same remark as getNextSourceFromRegSequence.
// I.e., this may be turned into an assert.
- return false;
+ return ValueTrackerResult();
if (!TII)
// We could handle the REG_SEQUENCE here, but we do not want to
// duplicate the code from the generic TII.
- return false;
+ return ValueTrackerResult();
TargetInstrInfo::RegSubRegPair BaseReg;
TargetInstrInfo::RegSubRegPairAndIdx InsertedReg;
if (!TII->getInsertSubregInputs(*Def, DefIdx, BaseReg, InsertedReg))
- return false;
+ return ValueTrackerResult();
// We are looking at:
// Def = INSERT_SUBREG v0, v1, sub1
// #1 Check if the inserted register matches the required sub index.
if (InsertedReg.SubIdx == DefSubReg) {
- SrcReg = InsertedReg.Reg;
- SrcSubReg = InsertedReg.SubReg;
- return true;
+ return ValueTrackerResult(InsertedReg.Reg, InsertedReg.SubReg);
}
// #2 Otherwise, if the sub register we are looking for is not partial
// defined by the inserted element, we can look through the main
// subregisters, bails out.
if (MRI.getRegClass(MODef.getReg()) != MRI.getRegClass(BaseReg.Reg) ||
BaseReg.SubReg)
- return false;
+ return ValueTrackerResult();
// Get the TRI and check if the inserted sub-register overlaps with the
// sub-register we are tracking.
if (!TRI ||
(TRI->getSubRegIndexLaneMask(DefSubReg) &
TRI->getSubRegIndexLaneMask(InsertedReg.SubIdx)) != 0)
- return false;
+ return ValueTrackerResult();
// At this point, the value is available in v0 via the same subreg
// we used for Def.
- SrcReg = BaseReg.Reg;
- SrcSubReg = DefSubReg;
- return true;
+ return ValueTrackerResult(BaseReg.Reg, DefSubReg);
}
-bool ValueTracker::getNextSourceFromExtractSubreg(unsigned &SrcReg,
- unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSourceFromExtractSubreg() {
assert((Def->isExtractSubreg() ||
Def->isExtractSubregLike()) && "Invalid definition");
// We are looking at:
// Bails if we have to compose sub registers.
// Indeed, if DefSubReg != 0, we would have to compose it with sub0.
if (DefSubReg)
- return false;
+ return ValueTrackerResult();
if (!TII)
// We could handle the EXTRACT_SUBREG here, but we do not want to
// duplicate the code from the generic TII.
- return false;
+ return ValueTrackerResult();
TargetInstrInfo::RegSubRegPairAndIdx ExtractSubregInputReg;
if (!TII->getExtractSubregInputs(*Def, DefIdx, ExtractSubregInputReg))
- return false;
+ return ValueTrackerResult();
// Bails if we have to compose sub registers.
// Likewise, if v0.subreg != 0, we would have to compose v0.subreg with sub0.
if (ExtractSubregInputReg.SubReg)
- return false;
+ return ValueTrackerResult();
// Otherwise, the value is available in the v0.sub0.
- SrcReg = ExtractSubregInputReg.Reg;
- SrcSubReg = ExtractSubregInputReg.SubIdx;
- return true;
+ return ValueTrackerResult(ExtractSubregInputReg.Reg, ExtractSubregInputReg.SubIdx);
}
-bool ValueTracker::getNextSourceFromSubregToReg(unsigned &SrcReg,
- unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSourceFromSubregToReg() {
assert(Def->isSubregToReg() && "Invalid definition");
// We are looking at:
// Def = SUBREG_TO_REG Imm, v0, sub0
// we track are included in sub0 and if yes, we would have to
// determine the right subreg in v0.
if (DefSubReg != Def->getOperand(3).getImm())
- return false;
+ return ValueTrackerResult();
// Bails if we have to compose sub registers.
// Likewise, if v0.subreg != 0, we would have to compose it with sub0.
if (Def->getOperand(2).getSubReg())
- return false;
+ return ValueTrackerResult();
- SrcReg = Def->getOperand(2).getReg();
- SrcSubReg = Def->getOperand(3).getImm();
- return true;
+ return ValueTrackerResult(Def->getOperand(2).getReg(),
+ Def->getOperand(3).getImm());
}
-bool ValueTracker::getNextSourceImpl(unsigned &SrcReg, unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSourceImpl() {
assert(Def && "This method needs a valid definition");
assert(
(DefIdx < Def->getDesc().getNumDefs() || Def->getDesc().isVariadic()) &&
Def->getOperand(DefIdx).isDef() && "Invalid DefIdx");
if (Def->isCopy())
- return getNextSourceFromCopy(SrcReg, SrcSubReg);
+ return getNextSourceFromCopy();
if (Def->isBitcast())
- return getNextSourceFromBitcast(SrcReg, SrcSubReg);
+ return getNextSourceFromBitcast();
// All the remaining cases involve "complex" instructions.
// Bails if we did not ask for the advanced tracking.
if (!UseAdvancedTracking)
- return false;
+ return ValueTrackerResult();
if (Def->isRegSequence() || Def->isRegSequenceLike())
- return getNextSourceFromRegSequence(SrcReg, SrcSubReg);
+ return getNextSourceFromRegSequence();
if (Def->isInsertSubreg() || Def->isInsertSubregLike())
- return getNextSourceFromInsertSubreg(SrcReg, SrcSubReg);
+ return getNextSourceFromInsertSubreg();
if (Def->isExtractSubreg() || Def->isExtractSubregLike())
- return getNextSourceFromExtractSubreg(SrcReg, SrcSubReg);
+ return getNextSourceFromExtractSubreg();
if (Def->isSubregToReg())
- return getNextSourceFromSubregToReg(SrcReg, SrcSubReg);
- return false;
+ return getNextSourceFromSubregToReg();
+ return ValueTrackerResult();
}
-const MachineInstr *ValueTracker::getNextSource(unsigned &SrcReg,
- unsigned &SrcSubReg) {
+ValueTrackerResult ValueTracker::getNextSource() {
// If we reach a point where we cannot move up in the use-def chain,
// there is nothing we can get.
if (!Def)
- return nullptr;
+ return ValueTrackerResult();
- const MachineInstr *PrevDef = nullptr;
- // Try to find the next source.
- if (getNextSourceImpl(SrcReg, SrcSubReg)) {
+ ValueTrackerResult Res = getNextSourceImpl();
+ if (Res.isValid()) {
// Update definition, definition index, and subregister for the
// next call of getNextSource.
// Update the current register.
- Reg = SrcReg;
- // Update the return value before moving up in the use-def chain.
- PrevDef = Def;
+ bool OneRegSrc = Res.getNumSources() == 1;
+ if (OneRegSrc)
+ Reg = Res.getSrcReg(0);
+ // Update the result before moving up in the use-def chain
+ // with the instruction containing the last found sources.
+ Res.setInst(Def);
+
// If we can still move up in the use-def chain, move to the next
// defintion.
- if (!TargetRegisterInfo::isPhysicalRegister(Reg)) {
+ if (!TargetRegisterInfo::isPhysicalRegister(Reg) && OneRegSrc) {
Def = MRI.getVRegDef(Reg);
DefIdx = MRI.def_begin(Reg).getOperandNo();
- DefSubReg = SrcSubReg;
- return PrevDef;
+ DefSubReg = Res.getSrcSubReg(0);
+ return Res;
}
}
// If we end up here, this means we will not be able to find another source
- // for the next iteration.
- // Make sure any new call to getNextSource bails out early by cutting the
- // use-def chain.
+ // for the next iteration. Make sure any new call to getNextSource bails out
+ // early by cutting the use-def chain.
Def = nullptr;
- return PrevDef;
+ return Res;
}
projects / oota-llvm.git / commitdiff