X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FCriticalAntiDepBreaker.cpp;h=bad50103b9c3ad372ae8235aa5daafea5684ec12;hb=aba6559370c3d453588103fb667ffa3b11b76652;hp=7b2ce3624170d24e99698a04033c3d1935a036b4;hpb=278ba1f9b6c14ddf79040979c88b978d41f8c036;p=oota-llvm.git diff --git a/lib/CodeGen/CriticalAntiDepBreaker.cpp b/lib/CodeGen/CriticalAntiDepBreaker.cpp index 7b2ce362417..bad50103b9c 100644 --- a/lib/CodeGen/CriticalAntiDepBreaker.cpp +++ b/lib/CodeGen/CriticalAntiDepBreaker.cpp @@ -27,15 +27,16 @@ using namespace llvm; CriticalAntiDepBreaker:: -CriticalAntiDepBreaker(MachineFunction& MFi) : +CriticalAntiDepBreaker(MachineFunction& MFi, const RegisterClassInfo &RCI) : AntiDepBreaker(), MF(MFi), MRI(MF.getRegInfo()), TII(MF.getTarget().getInstrInfo()), TRI(MF.getTarget().getRegisterInfo()), - AllocatableSet(TRI->getAllocatableSet(MF)), + RegClassInfo(RCI), Classes(TRI->getNumRegs(), static_cast(0)), KillIndices(TRI->getNumRegs(), 0), - DefIndices(TRI->getNumRegs(), 0) {} + DefIndices(TRI->getNumRegs(), 0), + KeepRegs(TRI->getNumRegs(), false) {} CriticalAntiDepBreaker::~CriticalAntiDepBreaker() { } @@ -52,9 +53,9 @@ void CriticalAntiDepBreaker::StartBlock(MachineBasicBlock *BB) { } // Clear "do not change" set. - KeepRegs.clear(); + KeepRegs.reset(); - bool IsReturnBlock = (!BB->empty() && BB->back().getDesc().isReturn()); + bool IsReturnBlock = (BBSize != 0 && BB->back().isReturn()); // Determine the live-out physregs for this block. if (IsReturnBlock) { @@ -63,14 +64,14 @@ void CriticalAntiDepBreaker::StartBlock(MachineBasicBlock *BB) { E = MRI.liveout_end(); I != E; ++I) { unsigned Reg = *I; Classes[Reg] = reinterpret_cast(-1); - KillIndices[Reg] = BB->size(); + KillIndices[Reg] = BBSize; DefIndices[Reg] = ~0u; // Repeat, for all aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + for (const uint16_t *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { unsigned AliasReg = *Alias; Classes[AliasReg] = reinterpret_cast(-1); - KillIndices[AliasReg] = BB->size(); + KillIndices[AliasReg] = BBSize; DefIndices[AliasReg] = ~0u; } } @@ -85,14 +86,14 @@ void CriticalAntiDepBreaker::StartBlock(MachineBasicBlock *BB) { E = (*SI)->livein_end(); I != E; ++I) { unsigned Reg = *I; Classes[Reg] = reinterpret_cast(-1); - KillIndices[Reg] = BB->size(); + KillIndices[Reg] = BBSize; DefIndices[Reg] = ~0u; // Repeat, for all aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + for (const uint16_t *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { unsigned AliasReg = *Alias; Classes[AliasReg] = reinterpret_cast(-1); - KillIndices[AliasReg] = BB->size(); + KillIndices[AliasReg] = BBSize; DefIndices[AliasReg] = ~0u; } } @@ -102,18 +103,18 @@ void CriticalAntiDepBreaker::StartBlock(MachineBasicBlock *BB) { // callee-saved register that is not saved in the prolog. const MachineFrameInfo *MFI = MF.getFrameInfo(); BitVector Pristine = MFI->getPristineRegs(BB); - for (const unsigned *I = TRI->getCalleeSavedRegs(); *I; ++I) { + for (const uint16_t *I = TRI->getCalleeSavedRegs(&MF); *I; ++I) { unsigned Reg = *I; if (!IsReturnBlock && !Pristine.test(Reg)) continue; Classes[Reg] = reinterpret_cast(-1); - KillIndices[Reg] = BB->size(); + KillIndices[Reg] = BBSize; DefIndices[Reg] = ~0u; // Repeat, for all aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + for (const uint16_t *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { unsigned AliasReg = *Alias; Classes[AliasReg] = reinterpret_cast(-1); - KillIndices[AliasReg] = BB->size(); + KillIndices[AliasReg] = BBSize; DefIndices[AliasReg] = ~0u; } } @@ -121,7 +122,7 @@ void CriticalAntiDepBreaker::StartBlock(MachineBasicBlock *BB) { void CriticalAntiDepBreaker::FinishBlock() { RegRefs.clear(); - KeepRegs.clear(); + KeepRegs.reset(); } void CriticalAntiDepBreaker::Observe(MachineInstr *MI, unsigned Count, @@ -193,8 +194,8 @@ void CriticalAntiDepBreaker::PrescanInstruction(MachineInstr *MI) { // instruction which may not be executed. The second R6 def may or may not // re-define R6 so it's not safe to change it since the last R6 use cannot be // changed. - bool Special = MI->getDesc().isCall() || - MI->getDesc().hasExtraSrcRegAllocReq() || + bool Special = MI->isCall() || + MI->hasExtraSrcRegAllocReq() || TII->isPredicated(MI); // Scan the register operands for this instruction and update @@ -207,7 +208,7 @@ void CriticalAntiDepBreaker::PrescanInstruction(MachineInstr *MI) { const TargetRegisterClass *NewRC = 0; if (i < MI->getDesc().getNumOperands()) - NewRC = MI->getDesc().OpInfo[i].getRegClass(TRI); + NewRC = TII->getRegClass(MI->getDesc(), i, TRI); // For now, only allow the register to be changed if its register // class is consistent across all uses. @@ -217,7 +218,7 @@ void CriticalAntiDepBreaker::PrescanInstruction(MachineInstr *MI) { Classes[Reg] = reinterpret_cast(-1); // Now check for aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + for (const uint16_t *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { // If an alias of the reg is used during the live range, give up. // Note that this allows us to skip checking if AntiDepReg // overlaps with any of the aliases, among other things. @@ -233,10 +234,11 @@ void CriticalAntiDepBreaker::PrescanInstruction(MachineInstr *MI) { RegRefs.insert(std::make_pair(Reg, &MO)); if (MO.isUse() && Special) { - if (KeepRegs.insert(Reg)) { - for (const unsigned *Subreg = TRI->getSubRegisters(Reg); + if (!KeepRegs.test(Reg)) { + KeepRegs.set(Reg); + for (const uint16_t *Subreg = TRI->getSubRegisters(Reg); *Subreg; ++Subreg) - KeepRegs.insert(*Subreg); + KeepRegs.set(*Subreg); } } } @@ -253,6 +255,17 @@ void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, // address updates. for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { MachineOperand &MO = MI->getOperand(i); + + if (MO.isRegMask()) + for (unsigned i = 0, e = TRI->getNumRegs(); i != e; ++i) + if (MO.clobbersPhysReg(i)) { + DefIndices[i] = Count; + KillIndices[i] = ~0u; + KeepRegs.reset(i); + Classes[i] = 0; + RegRefs.erase(i); + } + if (!MO.isReg()) continue; unsigned Reg = MO.getReg(); if (Reg == 0) continue; @@ -265,21 +278,21 @@ void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, assert(((KillIndices[Reg] == ~0u) != (DefIndices[Reg] == ~0u)) && "Kill and Def maps aren't consistent for Reg!"); - KeepRegs.erase(Reg); + KeepRegs.reset(Reg); Classes[Reg] = 0; RegRefs.erase(Reg); // Repeat, for all subregs. - for (const unsigned *Subreg = TRI->getSubRegisters(Reg); + for (const uint16_t *Subreg = TRI->getSubRegisters(Reg); *Subreg; ++Subreg) { unsigned SubregReg = *Subreg; DefIndices[SubregReg] = Count; KillIndices[SubregReg] = ~0u; - KeepRegs.erase(SubregReg); + KeepRegs.reset(SubregReg); Classes[SubregReg] = 0; RegRefs.erase(SubregReg); } // Conservatively mark super-registers as unusable. - for (const unsigned *Super = TRI->getSuperRegisters(Reg); + for (const uint16_t *Super = TRI->getSuperRegisters(Reg); *Super; ++Super) { unsigned SuperReg = *Super; Classes[SuperReg] = reinterpret_cast(-1); @@ -295,7 +308,7 @@ void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, const TargetRegisterClass *NewRC = 0; if (i < MI->getDesc().getNumOperands()) - NewRC = MI->getDesc().OpInfo[i].getRegClass(TRI); + NewRC = TII->getRegClass(MI->getDesc(), i, TRI); // For now, only allow the register to be changed if its register // class is consistent across all uses. @@ -315,7 +328,7 @@ void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, "Kill and Def maps aren't consistent for Reg!"); } // Repeat, for all aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + for (const uint16_t *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { unsigned AliasReg = *Alias; if (KillIndices[AliasReg] == ~0u) { KillIndices[AliasReg] = Count; @@ -325,17 +338,58 @@ void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, } } -// Check all machine instructions that define the antidependent register. -// Return true if any of these instructions define the new register. +// Check all machine operands that reference the antidependent register and must +// be replaced by NewReg. Return true if any of their parent instructions may +// clobber the new register. +// +// Note: AntiDepReg may be referenced by a two-address instruction such that +// it's use operand is tied to a def operand. We guard against the case in which +// the two-address instruction also defines NewReg, as may happen with +// pre/postincrement loads. In this case, both the use and def operands are in +// RegRefs because the def is inserted by PrescanInstruction and not erased +// during ScanInstruction. So checking for an instructions with definitions of +// both NewReg and AntiDepReg covers it. bool -CriticalAntiDepBreaker::isNewRegModifiedByRefs(RegRefIter RegRefBegin, - RegRefIter RegRefEnd, - unsigned NewReg) +CriticalAntiDepBreaker::isNewRegClobberedByRefs(RegRefIter RegRefBegin, + RegRefIter RegRefEnd, + unsigned NewReg) { for (RegRefIter I = RegRefBegin; I != RegRefEnd; ++I ) { - MachineOperand *MO = I->second; - if (MO->getParent()->modifiesRegister(NewReg, TRI)) + MachineOperand *RefOper = I->second; + + // Don't allow the instruction defining AntiDepReg to earlyclobber its + // operands, in case they may be assigned to NewReg. In this case antidep + // breaking must fail, but it's too rare to bother optimizing. + if (RefOper->isDef() && RefOper->isEarlyClobber()) return true; + + // Handle cases in which this instructions defines NewReg. + MachineInstr *MI = RefOper->getParent(); + for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + const MachineOperand &CheckOper = MI->getOperand(i); + + if (CheckOper.isRegMask() && CheckOper.clobbersPhysReg(NewReg)) + return true; + + if (!CheckOper.isReg() || !CheckOper.isDef() || + CheckOper.getReg() != NewReg) + continue; + + // Don't allow the instruction to define NewReg and AntiDepReg. + // When AntiDepReg is renamed it will be an illegal op. + if (RefOper->isDef()) + return true; + + // Don't allow an instruction using AntiDepReg to be earlyclobbered by + // NewReg + if (CheckOper.isEarlyClobber()) + return true; + + // Don't allow inline asm to define NewReg at all. Who know what it's + // doing with it. + if (MI->isInlineAsm()) + return true; + } } return false; } @@ -347,11 +401,9 @@ CriticalAntiDepBreaker::findSuitableFreeRegister(RegRefIter RegRefBegin, unsigned LastNewReg, const TargetRegisterClass *RC) { - for (TargetRegisterClass::iterator R = RC->allocation_order_begin(MF), - RE = RC->allocation_order_end(MF); R != RE; ++R) { - unsigned NewReg = *R; - // Don't consider non-allocatable registers - if (!AllocatableSet.test(NewReg)) continue; + ArrayRef Order = RegClassInfo.getOrder(RC); + for (unsigned i = 0; i != Order.size(); ++i) { + unsigned NewReg = Order[i]; // Don't replace a register with itself. if (NewReg == AntiDepReg) continue; // Don't replace a register with one that was recently used to repair @@ -361,7 +413,7 @@ CriticalAntiDepBreaker::findSuitableFreeRegister(RegRefIter RegRefBegin, // If any instructions that define AntiDepReg also define the NewReg, it's // not suitable. For example, Instruction with multiple definitions can // result in this condition. - if (isNewRegModifiedByRefs(RegRefBegin, RegRefEnd, NewReg)) continue; + if (isNewRegClobberedByRefs(RegRefBegin, RegRefEnd, NewReg)) continue; // If NewReg is dead and NewReg's most recent def is not before // AntiDepReg's kill, it's safe to replace AntiDepReg with NewReg. assert(((KillIndices[AntiDepReg] == ~0u) != (DefIndices[AntiDepReg] == ~0u)) @@ -383,13 +435,16 @@ unsigned CriticalAntiDepBreaker:: BreakAntiDependencies(const std::vector& SUnits, MachineBasicBlock::iterator Begin, MachineBasicBlock::iterator End, - unsigned InsertPosIndex) { + unsigned InsertPosIndex, + DbgValueVector &DbgValues) { // The code below assumes that there is at least one instruction, // so just duck out immediately if the block is empty. if (SUnits.empty()) return 0; // Keep a map of the MachineInstr*'s back to the SUnit representing them. // This is used for updating debug information. + // + // FIXME: Replace this with the existing map in ScheduleDAGInstrs::MISUnitMap DenseMap MISUnitMap; // Find the node at the bottom of the critical path. @@ -495,10 +550,10 @@ BreakAntiDependencies(const std::vector& SUnits, if (Edge->getKind() == SDep::Anti) { AntiDepReg = Edge->getReg(); assert(AntiDepReg != 0 && "Anti-dependence on reg0?"); - if (!AllocatableSet.test(AntiDepReg)) + if (!RegClassInfo.isAllocatable(AntiDepReg)) // Don't break anti-dependencies on non-allocatable registers. AntiDepReg = 0; - else if (KeepRegs.count(AntiDepReg)) + else if (KeepRegs.test(AntiDepReg)) // Don't break anti-dependencies if an use down below requires // this exact register. AntiDepReg = 0; @@ -535,7 +590,7 @@ BreakAntiDependencies(const std::vector& SUnits, // If MI's defs have a special allocation requirement, don't allow // any def registers to be changed. Also assume all registers // defined in a call must not be changed (ABI). - if (MI->getDesc().isCall() || MI->getDesc().hasExtraDefRegAllocReq() || + if (MI->isCall() || MI->hasExtraDefRegAllocReq() || TII->isPredicated(MI)) // If this instruction's defs have special allocation requirement, don't // break this anti-dependency. @@ -590,14 +645,10 @@ BreakAntiDependencies(const std::vector& SUnits, // as well. const SUnit *SU = MISUnitMap[Q->second->getParent()]; if (!SU) continue; - for (unsigned i = 0, e = SU->DbgInstrList.size() ; i < e ; ++i) { - MachineInstr *DI = SU->DbgInstrList[i]; - assert (DI->getNumOperands()==3 && DI->getOperand(0).isReg() && - DI->getOperand(0).getReg() - && "Non register dbg_value attached to SUnit!"); - if (DI->getOperand(0).getReg() == AntiDepReg) - DI->getOperand(0).setReg(NewReg); - } + for (DbgValueVector::iterator DVI = DbgValues.begin(), + DVE = DbgValues.end(); DVI != DVE; ++DVI) + if (DVI->second == Q->second->getParent()) + UpdateDbgValue(DVI->first, AntiDepReg, NewReg); } // We just went back in time and modified history; the