X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FCriticalAntiDepBreaker.cpp;h=18c8e0ae125096a58569b7896fc2affc581772ee;hb=66f464ee266b31bb02058c49a5abe3a6b77f080b;hp=4cac453abf452b3cff85524ccbf171972dd1ea0a;hpb=fa796dd720f1b34596a043f17f098fac18ecc028;p=oota-llvm.git diff --git a/lib/CodeGen/CriticalAntiDepBreaker.cpp b/lib/CodeGen/CriticalAntiDepBreaker.cpp index 4cac453abf4..18c8e0ae125 100644 --- a/lib/CodeGen/CriticalAntiDepBreaker.cpp +++ b/lib/CodeGen/CriticalAntiDepBreaker.cpp @@ -17,12 +17,12 @@ #include "CriticalAntiDepBreaker.h" #include "llvm/CodeGen/MachineBasicBlock.h" #include "llvm/CodeGen/MachineFrameInfo.h" -#include "llvm/Target/TargetMachine.h" -#include "llvm/Target/TargetInstrInfo.h" -#include "llvm/Target/TargetRegisterInfo.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetRegisterInfo.h" using namespace llvm; @@ -35,7 +35,8 @@ CriticalAntiDepBreaker(MachineFunction& MFi, const RegisterClassInfo &RCI) : 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() { } @@ -52,48 +53,20 @@ void CriticalAntiDepBreaker::StartBlock(MachineBasicBlock *BB) { } // Clear "do not change" set. - KeepRegs.clear(); - - bool IsReturnBlock = (!BB->empty() && BB->back().getDesc().isReturn()); - - // Determine the live-out physregs for this block. - if (IsReturnBlock) { - // In a return block, examine the function live-out regs. - for (MachineRegisterInfo::liveout_iterator I = MRI.liveout_begin(), - E = MRI.liveout_end(); I != E; ++I) { - unsigned Reg = *I; - Classes[Reg] = reinterpret_cast(-1); - KillIndices[Reg] = BB->size(); - DefIndices[Reg] = ~0u; + KeepRegs.reset(); - // Repeat, for all aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { - unsigned AliasReg = *Alias; - Classes[AliasReg] = reinterpret_cast(-1); - KillIndices[AliasReg] = BB->size(); - DefIndices[AliasReg] = ~0u; - } - } - } + bool IsReturnBlock = (BBSize != 0 && BB->back().isReturn()); - // In a non-return block, examine the live-in regs of all successors. - // Note a return block can have successors if the return instruction is - // predicated. + // Examine the live-in regs of all successors. for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(), SE = BB->succ_end(); SI != SE; ++SI) for (MachineBasicBlock::livein_iterator I = (*SI)->livein_begin(), E = (*SI)->livein_end(); I != E; ++I) { - unsigned Reg = *I; - Classes[Reg] = reinterpret_cast(-1); - KillIndices[Reg] = BB->size(); - DefIndices[Reg] = ~0u; - - // Repeat, for all aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { - unsigned AliasReg = *Alias; - Classes[AliasReg] = reinterpret_cast(-1); - KillIndices[AliasReg] = BB->size(); - DefIndices[AliasReg] = ~0u; + for (MCRegAliasIterator AI(*I, TRI, true); AI.isValid(); ++AI) { + unsigned Reg = *AI; + Classes[Reg] = reinterpret_cast(-1); + KillIndices[Reg] = BBSize; + DefIndices[Reg] = ~0u; } } @@ -102,26 +75,20 @@ 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) { - unsigned Reg = *I; - if (!IsReturnBlock && !Pristine.test(Reg)) continue; - Classes[Reg] = reinterpret_cast(-1); - KillIndices[Reg] = BB->size(); - DefIndices[Reg] = ~0u; - - // Repeat, for all aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { - unsigned AliasReg = *Alias; - Classes[AliasReg] = reinterpret_cast(-1); - KillIndices[AliasReg] = BB->size(); - DefIndices[AliasReg] = ~0u; + for (const uint16_t *I = TRI->getCalleeSavedRegs(&MF); *I; ++I) { + if (!IsReturnBlock && !Pristine.test(*I)) continue; + for (MCRegAliasIterator AI(*I, TRI, true); AI.isValid(); ++AI) { + unsigned Reg = *AI; + Classes[Reg] = reinterpret_cast(-1); + KillIndices[Reg] = BBSize; + DefIndices[Reg] = ~0u; } } } void CriticalAntiDepBreaker::FinishBlock() { RegRefs.clear(); - KeepRegs.clear(); + KeepRegs.reset(); } void CriticalAntiDepBreaker::Observe(MachineInstr *MI, unsigned Count, @@ -193,8 +160,8 @@ 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 +174,7 @@ 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, MF); // For now, only allow the register to be changed if its register // class is consistent across all uses. @@ -217,11 +184,11 @@ void CriticalAntiDepBreaker::PrescanInstruction(MachineInstr *MI) { Classes[Reg] = reinterpret_cast(-1); // Now check for aliases. - for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) { + for (MCRegAliasIterator AI(Reg, TRI, false); AI.isValid(); ++AI) { // 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. - unsigned AliasReg = *Alias; + unsigned AliasReg = *AI; if (Classes[AliasReg]) { Classes[AliasReg] = reinterpret_cast(-1); Classes[Reg] = reinterpret_cast(-1); @@ -233,10 +200,10 @@ 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); - *Subreg; ++Subreg) - KeepRegs.insert(*Subreg); + if (!KeepRegs.test(Reg)) { + for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true); + SubRegs.isValid(); ++SubRegs) + KeepRegs.set(*SubRegs); } } } @@ -245,7 +212,7 @@ void CriticalAntiDepBreaker::PrescanInstruction(MachineInstr *MI) { void CriticalAntiDepBreaker::ScanInstruction(MachineInstr *MI, unsigned Count) { // Update liveness. - // Proceding upwards, registers that are defed but not used in this + // Proceeding upwards, registers that are defed but not used in this // instruction are now dead. if (!TII->isPredicated(MI)) { @@ -253,6 +220,17 @@ 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; @@ -265,25 +243,21 @@ 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); - *Subreg; ++Subreg) { - unsigned SubregReg = *Subreg; + for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) { + unsigned SubregReg = *SubRegs; 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); - *Super; ++Super) { - unsigned SuperReg = *Super; - Classes[SuperReg] = reinterpret_cast(-1); - } + for (MCSuperRegIterator SR(Reg, TRI); SR.isValid(); ++SR) + Classes[*SR] = reinterpret_cast(-1); } } for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { @@ -295,7 +269,7 @@ 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, MF); // For now, only allow the register to be changed if its register // class is consistent across all uses. @@ -315,8 +289,8 @@ 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) { - unsigned AliasReg = *Alias; + for (MCRegAliasIterator AI(Reg, TRI, false); AI.isValid(); ++AI) { + unsigned AliasReg = *AI; if (KillIndices[AliasReg] == ~0u) { KillIndices[AliasReg] = Count; DefIndices[AliasReg] = ~0u; @@ -355,6 +329,9 @@ CriticalAntiDepBreaker::isNewRegClobberedByRefs(RegRefIter RegRefBegin, 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; @@ -378,14 +355,15 @@ CriticalAntiDepBreaker::isNewRegClobberedByRefs(RegRefIter RegRefBegin, return false; } -unsigned -CriticalAntiDepBreaker::findSuitableFreeRegister(RegRefIter RegRefBegin, - RegRefIter RegRefEnd, - unsigned AntiDepReg, - unsigned LastNewReg, - const TargetRegisterClass *RC) +unsigned CriticalAntiDepBreaker:: +findSuitableFreeRegister(RegRefIter RegRefBegin, + RegRefIter RegRefEnd, + unsigned AntiDepReg, + unsigned LastNewReg, + const TargetRegisterClass *RC, + SmallVectorImpl &Forbid) { - ArrayRef Order = RegClassInfo.getOrder(RC); + ArrayRef Order = RegClassInfo.getOrder(RC); for (unsigned i = 0; i != Order.size(); ++i) { unsigned NewReg = Order[i]; // Don't replace a register with itself. @@ -408,6 +386,15 @@ CriticalAntiDepBreaker::findSuitableFreeRegister(RegRefIter RegRefBegin, Classes[NewReg] == reinterpret_cast(-1) || KillIndices[AntiDepReg] > DefIndices[NewReg]) continue; + // If NewReg overlaps any of the forbidden registers, we can't use it. + bool Forbidden = false; + for (SmallVectorImpl::iterator it = Forbid.begin(), + ite = Forbid.end(); it != ite; ++it) + if (TRI->regsOverlap(NewReg, *it)) { + Forbidden = true; + break; + } + if (Forbidden) continue; return NewReg; } @@ -427,6 +414,8 @@ BreakAntiDependencies(const std::vector& SUnits, // 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. @@ -532,10 +521,10 @@ BreakAntiDependencies(const std::vector& SUnits, if (Edge->getKind() == SDep::Anti) { AntiDepReg = Edge->getReg(); assert(AntiDepReg != 0 && "Anti-dependence on reg0?"); - if (!RegClassInfo.isAllocatable(AntiDepReg)) + if (!MRI.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; @@ -569,17 +558,21 @@ BreakAntiDependencies(const std::vector& SUnits, PrescanInstruction(MI); + SmallVector ForbidRegs; + // 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. AntiDepReg = 0; else if (AntiDepReg) { // If this instruction has a use of AntiDepReg, breaking it - // is invalid. + // is invalid. If the instruction defines other registers, + // save a list of them so that we don't pick a new register + // that overlaps any of them. for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { MachineOperand &MO = MI->getOperand(i); if (!MO.isReg()) continue; @@ -589,6 +582,8 @@ BreakAntiDependencies(const std::vector& SUnits, AntiDepReg = 0; break; } + if (MO.isDef() && Reg != AntiDepReg) + ForbidRegs.push_back(Reg); } } @@ -611,7 +606,7 @@ BreakAntiDependencies(const std::vector& SUnits, if (unsigned NewReg = findSuitableFreeRegister(Range.first, Range.second, AntiDepReg, LastNewReg[AntiDepReg], - RC)) { + RC, ForbidRegs)) { DEBUG(dbgs() << "Breaking anti-dependence edge on " << TRI->getName(AntiDepReg) << " with " << RegRefs.count(AntiDepReg) << " references"