-//===----- AggressiveAntiDepBreaker.cpp - Anti-dep breaker -------- ---------===//
+//===----- AggressiveAntiDepBreaker.cpp - Anti-dep breaker ----------------===//
//
// The LLVM Compiler Infrastructure
//
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "post-RA-sched"
#include "AggressiveAntiDepBreaker.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/CodeGen/RegisterClassInfo.h"
#include "llvm/Support/CommandLine.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/TargetRegisterInfo.h"
using namespace llvm;
+#define DEBUG_TYPE "post-RA-sched"
+
// If DebugDiv > 0 then only break antidep with (ID % DebugDiv) == DebugMod
static cl::opt<int>
DebugDiv("agg-antidep-debugdiv",
- cl::desc("Debug control for aggressive anti-dep breaker"),
- cl::init(0), cl::Hidden);
+ cl::desc("Debug control for aggressive anti-dep breaker"),
+ cl::init(0), cl::Hidden);
static cl::opt<int>
DebugMod("agg-antidep-debugmod",
- cl::desc("Debug control for aggressive anti-dep breaker"),
- cl::init(0), cl::Hidden);
+ cl::desc("Debug control for aggressive anti-dep breaker"),
+ cl::init(0), cl::Hidden);
AggressiveAntiDepState::AggressiveAntiDepState(const unsigned TargetRegs,
MachineBasicBlock *BB) :
- NumTargetRegs(TargetRegs), GroupNodes(TargetRegs, 0) {
-
+ NumTargetRegs(TargetRegs), GroupNodes(TargetRegs, 0),
+ GroupNodeIndices(TargetRegs, 0),
+ KillIndices(TargetRegs, 0),
+ DefIndices(TargetRegs, 0)
+{
const unsigned BBSize = BB->size();
for (unsigned i = 0; i < NumTargetRegs; ++i) {
// Initialize all registers to be in their own group. Initially we
}
}
-unsigned AggressiveAntiDepState::GetGroup(unsigned Reg)
-{
+unsigned AggressiveAntiDepState::GetGroup(unsigned Reg) {
unsigned Node = GroupNodeIndices[Reg];
while (GroupNodes[Node] != Node)
Node = GroupNodes[Node];
{
assert(GroupNodes[0] == 0 && "GroupNode 0 not parent!");
assert(GroupNodeIndices[0] == 0 && "Reg 0 not in Group 0!");
-
+
// find group for each register
unsigned Group1 = GetGroup(Reg1);
unsigned Group2 = GetGroup(Reg2);
-
+
// if either group is 0, then that must become the parent
unsigned Parent = (Group1 == 0) ? Group1 : Group2;
unsigned Other = (Parent == Group1) ? Group2 : Group1;
GroupNodes.at(Other) = Parent;
return Parent;
}
-
+
unsigned AggressiveAntiDepState::LeaveGroup(unsigned Reg)
{
// Create a new GroupNode for Reg. Reg's existing GroupNode must
return((KillIndices[Reg] != ~0u) && (DefIndices[Reg] == ~0u));
}
-
-
-AggressiveAntiDepBreaker::
-AggressiveAntiDepBreaker(MachineFunction& MFi,
- TargetSubtarget::RegClassVector& CriticalPathRCs) :
- AntiDepBreaker(), MF(MFi),
- MRI(MF.getRegInfo()),
- TRI(MF.getTarget().getRegisterInfo()),
- AllocatableSet(TRI->getAllocatableSet(MF)),
- State(NULL) {
+AggressiveAntiDepBreaker::AggressiveAntiDepBreaker(
+ MachineFunction &MFi, const RegisterClassInfo &RCI,
+ TargetSubtargetInfo::RegClassVector &CriticalPathRCs)
+ : AntiDepBreaker(), MF(MFi), MRI(MF.getRegInfo()),
+ TII(MF.getSubtarget().getInstrInfo()),
+ TRI(MF.getSubtarget().getRegisterInfo()), RegClassInfo(RCI),
+ State(nullptr) {
/* Collect a bitset of all registers that are only broken if they
are on the critical path. */
for (unsigned i = 0, e = CriticalPathRCs.size(); i < e; ++i) {
else
CriticalPathSet |= CPSet;
}
-
+
DEBUG(dbgs() << "AntiDep Critical-Path Registers:");
- DEBUG(for (int r = CriticalPathSet.find_first(); r != -1;
+ DEBUG(for (int r = CriticalPathSet.find_first(); r != -1;
r = CriticalPathSet.find_next(r))
dbgs() << " " << TRI->getName(r));
DEBUG(dbgs() << '\n');
}
void AggressiveAntiDepBreaker::StartBlock(MachineBasicBlock *BB) {
- assert(State == NULL);
+ assert(!State);
State = new AggressiveAntiDepState(TRI->getNumRegs(), BB);
- bool IsReturnBlock = (!BB->empty() && BB->back().getDesc().isReturn());
- unsigned *KillIndices = State->GetKillIndices();
- unsigned *DefIndices = State->GetDefIndices();
+ bool IsReturnBlock = BB->isReturnBlock();
+ std::vector<unsigned> &KillIndices = State->GetKillIndices();
+ std::vector<unsigned> &DefIndices = State->GetDefIndices();
- // 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;
- State->UnionGroups(Reg, 0);
- KillIndices[Reg] = BB->size();
- DefIndices[Reg] = ~0u;
- // Repeat, for all aliases.
- for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
- State->UnionGroups(AliasReg, 0);
- KillIndices[AliasReg] = BB->size();
- DefIndices[AliasReg] = ~0u;
- }
- }
- } else {
- // In a non-return block, examine the live-in regs of all successors.
- for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),
+ // 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;
+ for (const auto &LI : (*SI)->liveins()) {
+ for (MCRegAliasIterator AI(LI.PhysReg, TRI, true); AI.isValid(); ++AI) {
+ unsigned Reg = *AI;
State->UnionGroups(Reg, 0);
KillIndices[Reg] = BB->size();
DefIndices[Reg] = ~0u;
- // Repeat, for all aliases.
- for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
- State->UnionGroups(AliasReg, 0);
- KillIndices[AliasReg] = BB->size();
- DefIndices[AliasReg] = ~0u;
- }
}
- }
+ }
// Mark live-out callee-saved registers. In a return block this is
// all callee-saved registers. In non-return this is any
// 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) {
+ BitVector Pristine = MFI->getPristineRegs(MF);
+ for (const MCPhysReg *I = TRI->getCalleeSavedRegs(&MF); *I; ++I) {
unsigned Reg = *I;
if (!IsReturnBlock && !Pristine.test(Reg)) continue;
- State->UnionGroups(Reg, 0);
- KillIndices[Reg] = BB->size();
- DefIndices[Reg] = ~0u;
- // Repeat, for all aliases.
- for (const unsigned *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
+ for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
+ unsigned AliasReg = *AI;
State->UnionGroups(AliasReg, 0);
KillIndices[AliasReg] = BB->size();
DefIndices[AliasReg] = ~0u;
void AggressiveAntiDepBreaker::FinishBlock() {
delete State;
- State = NULL;
+ State = nullptr;
}
void AggressiveAntiDepBreaker::Observe(MachineInstr *MI, unsigned Count,
- unsigned InsertPosIndex) {
+ unsigned InsertPosIndex) {
assert(Count < InsertPosIndex && "Instruction index out of expected range!");
std::set<unsigned> PassthruRegs;
DEBUG(MI->dump());
DEBUG(dbgs() << "\tRegs:");
- unsigned *DefIndices = State->GetDefIndices();
+ std::vector<unsigned> &DefIndices = State->GetDefIndices();
for (unsigned Reg = 0; Reg != TRI->getNumRegs(); ++Reg) {
// If Reg is current live, then mark that it can't be renamed as
// we don't know the extent of its live-range anymore (now that it
// schedule region).
if (State->IsLive(Reg)) {
DEBUG(if (State->GetGroup(Reg) != 0)
- dbgs() << " " << TRI->getName(Reg) << "=g" <<
+ dbgs() << " " << TRI->getName(Reg) << "=g" <<
State->GetGroup(Reg) << "->g0(region live-out)");
State->UnionGroups(Reg, 0);
- } else if ((DefIndices[Reg] < InsertPosIndex) && (DefIndices[Reg] >= Count)) {
+ } else if ((DefIndices[Reg] < InsertPosIndex)
+ && (DefIndices[Reg] >= Count)) {
DefIndices[Reg] = Count;
}
}
}
bool AggressiveAntiDepBreaker::IsImplicitDefUse(MachineInstr *MI,
- MachineOperand& MO)
+ MachineOperand& MO)
{
if (!MO.isReg() || !MO.isImplicit())
return false;
if (Reg == 0)
return false;
- MachineOperand *Op = NULL;
+ MachineOperand *Op = nullptr;
if (MO.isDef())
Op = MI->findRegisterUseOperand(Reg, true);
else
Op = MI->findRegisterDefOperand(Reg);
- return((Op != NULL) && Op->isImplicit());
+ return(Op && Op->isImplicit());
}
void AggressiveAntiDepBreaker::GetPassthruRegs(MachineInstr *MI,
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg()) continue;
- if ((MO.isDef() && MI->isRegTiedToUseOperand(i)) ||
+ if ((MO.isDef() && MI->isRegTiedToUseOperand(i)) ||
IsImplicitDefUse(MI, MO)) {
const unsigned Reg = MO.getReg();
- PassthruRegs.insert(Reg);
- for (const unsigned *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- PassthruRegs.insert(*Subreg);
- }
+ for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
+ SubRegs.isValid(); ++SubRegs)
+ PassthruRegs.insert(*SubRegs);
}
}
}
/// AntiDepEdges - Return in Edges the anti- and output- dependencies
/// in SU that we want to consider for breaking.
-static void AntiDepEdges(SUnit *SU, std::vector<SDep*>& Edges) {
+static void AntiDepEdges(const SUnit *SU, std::vector<const SDep*>& Edges) {
SmallSet<unsigned, 4> RegSet;
- for (SUnit::pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
+ for (SUnit::const_pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
P != PE; ++P) {
if ((P->getKind() == SDep::Anti) || (P->getKind() == SDep::Output)) {
- unsigned Reg = P->getReg();
- if (RegSet.count(Reg) == 0) {
+ if (RegSet.insert(P->getReg()).second)
Edges.push_back(&*P);
- RegSet.insert(Reg);
- }
}
}
}
/// CriticalPathStep - Return the next SUnit after SU on the bottom-up
/// critical path.
-static SUnit *CriticalPathStep(SUnit *SU) {
- SDep *Next = 0;
+static const SUnit *CriticalPathStep(const SUnit *SU) {
+ const SDep *Next = nullptr;
unsigned NextDepth = 0;
// Find the predecessor edge with the greatest depth.
- if (SU != 0) {
- for (SUnit::pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
+ if (SU) {
+ for (SUnit::const_pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
P != PE; ++P) {
- SUnit *PredSU = P->getSUnit();
+ const SUnit *PredSU = P->getSUnit();
unsigned PredLatency = P->getLatency();
unsigned PredTotalLatency = PredSU->getDepth() + PredLatency;
// In the case of a latency tie, prefer an anti-dependency edge over
}
}
- return (Next) ? Next->getSUnit() : 0;
+ return (Next) ? Next->getSUnit() : nullptr;
}
void AggressiveAntiDepBreaker::HandleLastUse(unsigned Reg, unsigned KillIdx,
- const char *tag, const char *header,
+ const char *tag,
+ const char *header,
const char *footer) {
- unsigned *KillIndices = State->GetKillIndices();
- unsigned *DefIndices = State->GetDefIndices();
- std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
+ std::vector<unsigned> &KillIndices = State->GetKillIndices();
+ std::vector<unsigned> &DefIndices = State->GetDefIndices();
+ std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
RegRefs = State->GetRegRefs();
+ // FIXME: We must leave subregisters of live super registers as live, so that
+ // we don't clear out the register tracking information for subregisters of
+ // super registers we're still tracking (and with which we're unioning
+ // subregister definitions).
+ for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+ if (TRI->isSuperRegister(Reg, *AI) && State->IsLive(*AI)) {
+ DEBUG(if (!header && footer) dbgs() << footer);
+ return;
+ }
+
if (!State->IsLive(Reg)) {
KillIndices[Reg] = KillIdx;
DefIndices[Reg] = ~0u;
RegRefs.erase(Reg);
State->LeaveGroup(Reg);
- DEBUG(if (header != NULL) {
- dbgs() << header << TRI->getName(Reg); header = NULL; });
+ DEBUG(if (header) {
+ dbgs() << header << TRI->getName(Reg); header = nullptr; });
DEBUG(dbgs() << "->g" << State->GetGroup(Reg) << tag);
}
// Repeat for subregisters.
- for (const unsigned *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- unsigned SubregReg = *Subreg;
+ for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
+ unsigned SubregReg = *SubRegs;
if (!State->IsLive(SubregReg)) {
KillIndices[SubregReg] = KillIdx;
DefIndices[SubregReg] = ~0u;
RegRefs.erase(SubregReg);
State->LeaveGroup(SubregReg);
- DEBUG(if (header != NULL) {
- dbgs() << header << TRI->getName(Reg); header = NULL; });
+ DEBUG(if (header) {
+ dbgs() << header << TRI->getName(Reg); header = nullptr; });
DEBUG(dbgs() << " " << TRI->getName(SubregReg) << "->g" <<
State->GetGroup(SubregReg) << tag);
}
}
- DEBUG(if ((header == NULL) && (footer != NULL)) dbgs() << footer);
+ DEBUG(if (!header && footer) dbgs() << footer);
}
-void AggressiveAntiDepBreaker::PrescanInstruction(MachineInstr *MI, unsigned Count,
- std::set<unsigned>& PassthruRegs) {
- unsigned *DefIndices = State->GetDefIndices();
- std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
+void AggressiveAntiDepBreaker::PrescanInstruction(MachineInstr *MI,
+ unsigned Count,
+ std::set<unsigned>& PassthruRegs) {
+ std::vector<unsigned> &DefIndices = State->GetDefIndices();
+ std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
RegRefs = State->GetRegRefs();
// Handle dead defs by simulating a last-use of the register just
- // after the def. A dead def can occur because the def is truely
+ // after the def. A dead def can occur because the def is truly
// dead, or because only a subregister is live at the def. If we
// don't do this the dead def will be incorrectly merged into the
// previous def.
if (!MO.isReg() || !MO.isDef()) continue;
unsigned Reg = MO.getReg();
if (Reg == 0) continue;
-
+
HandleLastUse(Reg, Count + 1, "", "\tDead Def: ", "\n");
}
unsigned Reg = MO.getReg();
if (Reg == 0) continue;
- DEBUG(dbgs() << " " << TRI->getName(Reg) << "=g" << State->GetGroup(Reg));
+ DEBUG(dbgs() << " " << TRI->getName(Reg) << "=g" << State->GetGroup(Reg));
// 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()) {
+ // defined in a call must not be changed (ABI). Inline assembly may
+ // reference either system calls or the register directly. Skip it until we
+ // can tell user specified registers from compiler-specified.
+ if (MI->isCall() || MI->hasExtraDefRegAllocReq() ||
+ TII->isPredicated(MI) || MI->isInlineAsm()) {
DEBUG(if (State->GetGroup(Reg) != 0) dbgs() << "->g0(alloc-req)");
State->UnionGroups(Reg, 0);
}
// Any aliased that are live at this point are completely or
// partially defined here, so group those aliases with Reg.
- 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 (State->IsLive(AliasReg)) {
State->UnionGroups(Reg, AliasReg);
- DEBUG(dbgs() << "->g" << State->GetGroup(Reg) << "(via " <<
+ DEBUG(dbgs() << "->g" << State->GetGroup(Reg) << "(via " <<
TRI->getName(AliasReg) << ")");
}
}
-
+
// Note register reference...
- const TargetRegisterClass *RC = NULL;
+ const TargetRegisterClass *RC = nullptr;
if (i < MI->getDesc().getNumOperands())
- RC = MI->getDesc().OpInfo[i].getRegClass(TRI);
+ RC = TII->getRegClass(MI->getDesc(), i, TRI, MF);
AggressiveAntiDepState::RegisterReference RR = { &MO, RC };
RegRefs.insert(std::make_pair(Reg, RR));
}
unsigned Reg = MO.getReg();
if (Reg == 0) continue;
// Ignore KILLs and passthru registers for liveness...
- if ((MI->getOpcode() == TargetInstrInfo::KILL) ||
- (PassthruRegs.count(Reg) != 0))
+ if (MI->isKill() || (PassthruRegs.count(Reg) != 0))
continue;
// Update def for Reg and aliases.
- DefIndices[Reg] = Count;
- for (const unsigned *Alias = TRI->getAliasSet(Reg);
- *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
- DefIndices[AliasReg] = Count;
+ for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
+ // We need to be careful here not to define already-live super registers.
+ // If the super register is already live, then this definition is not
+ // a definition of the whole super register (just a partial insertion
+ // into it). Earlier subregister definitions (which we've not yet visited
+ // because we're iterating bottom-up) need to be linked to the same group
+ // as this definition.
+ if (TRI->isSuperRegister(Reg, *AI) && State->IsLive(*AI))
+ continue;
+
+ DefIndices[*AI] = Count;
}
}
}
void AggressiveAntiDepBreaker::ScanInstruction(MachineInstr *MI,
- unsigned Count) {
+ unsigned Count) {
DEBUG(dbgs() << "\tUse Groups:");
- std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
+ std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
RegRefs = State->GetRegRefs();
+ // If MI's uses have special allocation requirement, don't allow
+ // any use registers to be changed. Also assume all registers
+ // used in a call must not be changed (ABI).
+ // Inline Assembly register uses also cannot be safely changed.
+ // FIXME: The issue with predicated instruction is more complex. We are being
+ // conservatively here because the kill markers cannot be trusted after
+ // if-conversion:
+ // %R6<def> = LDR %SP, %reg0, 92, pred:14, pred:%reg0; mem:LD4[FixedStack14]
+ // ...
+ // STR %R0, %R6<kill>, %reg0, 0, pred:0, pred:%CPSR; mem:ST4[%395]
+ // %R6<def> = LDR %SP, %reg0, 100, pred:0, pred:%CPSR; mem:LD4[FixedStack12]
+ // STR %R0, %R6<kill>, %reg0, 0, pred:14, pred:%reg0; mem:ST4[%396](align=8)
+ //
+ // The first R6 kill is not really a kill since it's killed by a predicated
+ // 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->isCall() ||
+ MI->hasExtraSrcRegAllocReq() ||
+ TII->isPredicated(MI) || MI->isInlineAsm();
+
// Scan the register uses for this instruction and update
// live-ranges, groups and RegRefs.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
if (!MO.isReg() || !MO.isUse()) continue;
unsigned Reg = MO.getReg();
if (Reg == 0) continue;
-
- DEBUG(dbgs() << " " << TRI->getName(Reg) << "=g" <<
- State->GetGroup(Reg));
+
+ DEBUG(dbgs() << " " << TRI->getName(Reg) << "=g" <<
+ State->GetGroup(Reg));
// It wasn't previously live but now it is, this is a kill. Forget
// the previous live-range information and start a new live-range
// for the register.
HandleLastUse(Reg, Count, "(last-use)");
- // If MI's uses have special allocation requirement, don't allow
- // any use registers to be changed. Also assume all registers
- // used in a call must not be changed (ABI).
- if (MI->getDesc().isCall() || MI->getDesc().hasExtraSrcRegAllocReq()) {
+ if (Special) {
DEBUG(if (State->GetGroup(Reg) != 0) dbgs() << "->g0(alloc-req)");
State->UnionGroups(Reg, 0);
}
// Note register reference...
- const TargetRegisterClass *RC = NULL;
+ const TargetRegisterClass *RC = nullptr;
if (i < MI->getDesc().getNumOperands())
- RC = MI->getDesc().OpInfo[i].getRegClass(TRI);
+ RC = TII->getRegClass(MI->getDesc(), i, TRI, MF);
AggressiveAntiDepState::RegisterReference RR = { &MO, RC };
RegRefs.insert(std::make_pair(Reg, RR));
}
-
+
DEBUG(dbgs() << '\n');
// Form a group of all defs and uses of a KILL instruction to ensure
// that all registers are renamed as a group.
- if (MI->getOpcode() == TargetInstrInfo::KILL) {
+ if (MI->isKill()) {
DEBUG(dbgs() << "\tKill Group:");
unsigned FirstReg = 0;
if (!MO.isReg()) continue;
unsigned Reg = MO.getReg();
if (Reg == 0) continue;
-
+
if (FirstReg != 0) {
DEBUG(dbgs() << "=" << TRI->getName(Reg));
State->UnionGroups(FirstReg, Reg);
FirstReg = Reg;
}
}
-
+
DEBUG(dbgs() << "->g" << State->GetGroup(FirstReg) << '\n');
}
}
// Check all references that need rewriting for Reg. For each, use
// the corresponding register class to narrow the set of registers
// that are appropriate for renaming.
- std::pair<std::multimap<unsigned,
- AggressiveAntiDepState::RegisterReference>::iterator,
- std::multimap<unsigned,
- AggressiveAntiDepState::RegisterReference>::iterator>
- Range = State->GetRegRefs().equal_range(Reg);
- for (std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>::iterator
- Q = Range.first, QE = Range.second; Q != QE; ++Q) {
- const TargetRegisterClass *RC = Q->second.RC;
- if (RC == NULL) continue;
+ for (const auto &Q : make_range(State->GetRegRefs().equal_range(Reg))) {
+ const TargetRegisterClass *RC = Q.second.RC;
+ if (!RC) continue;
BitVector RCBV = TRI->getAllocatableSet(MF, RC);
if (first) {
BV &= RCBV;
}
- DEBUG(dbgs() << " " << RC->getName());
+ DEBUG(dbgs() << " " << TRI->getRegClassName(RC));
}
-
+
return BV;
-}
+}
bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
unsigned AntiDepGroupIndex,
RenameOrderType& RenameOrder,
std::map<unsigned, unsigned> &RenameMap) {
- unsigned *KillIndices = State->GetKillIndices();
- unsigned *DefIndices = State->GetDefIndices();
- std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
+ std::vector<unsigned> &KillIndices = State->GetKillIndices();
+ std::vector<unsigned> &DefIndices = State->GetDefIndices();
+ std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
RegRefs = State->GetRegRefs();
// Collect all referenced registers in the same group as
// Find the "superest" register in the group. At the same time,
// collect the BitVector of registers that can be used to rename
// each register.
- DEBUG(dbgs() << "\tRename Candidates for Group g" << AntiDepGroupIndex << ":\n");
+ DEBUG(dbgs() << "\tRename Candidates for Group g" << AntiDepGroupIndex
+ << ":\n");
std::map<unsigned, BitVector> RenameRegisterMap;
unsigned SuperReg = 0;
for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
// If Reg has any references, then collect possible rename regs
if (RegRefs.count(Reg) > 0) {
DEBUG(dbgs() << "\t\t" << TRI->getName(Reg) << ":");
-
+
BitVector BV = GetRenameRegisters(Reg);
RenameRegisterMap.insert(std::pair<unsigned, BitVector>(Reg, BV));
unsigned Reg = Regs[i];
if (Reg == SuperReg) continue;
bool IsSub = TRI->isSubRegister(SuperReg, Reg);
- assert(IsSub && "Expecting group subregister");
+ // FIXME: remove this once PR18663 has been properly fixed. For now,
+ // return a conservative answer:
+ // assert(IsSub && "Expecting group subregister");
if (!IsSub)
return false;
}
static int renamecnt = 0;
if (renamecnt++ % DebugDiv != DebugMod)
return false;
-
+
dbgs() << "*** Performing rename " << TRI->getName(SuperReg) <<
" for debug ***\n";
}
// order. If that register is available, and the corresponding
// registers are available for the other group subregisters, then we
// can use those registers to rename.
- const TargetRegisterClass *SuperRC =
- TRI->getPhysicalRegisterRegClass(SuperReg, MVT::Other);
-
- const TargetRegisterClass::iterator RB = SuperRC->allocation_order_begin(MF);
- const TargetRegisterClass::iterator RE = SuperRC->allocation_order_end(MF);
- if (RB == RE) {
+
+ // FIXME: Using getMinimalPhysRegClass is very conservative. We should
+ // check every use of the register and find the largest register class
+ // that can be used in all of them.
+ const TargetRegisterClass *SuperRC =
+ TRI->getMinimalPhysRegClass(SuperReg, MVT::Other);
+
+ ArrayRef<MCPhysReg> Order = RegClassInfo.getOrder(SuperRC);
+ if (Order.empty()) {
DEBUG(dbgs() << "\tEmpty Super Regclass!!\n");
return false;
}
DEBUG(dbgs() << "\tFind Registers:");
- if (RenameOrder.count(SuperRC) == 0)
- RenameOrder.insert(RenameOrderType::value_type(SuperRC, RE));
+ RenameOrder.insert(RenameOrderType::value_type(SuperRC, Order.size()));
- const TargetRegisterClass::iterator OrigR = RenameOrder[SuperRC];
- const TargetRegisterClass::iterator EndR = ((OrigR == RE) ? RB : OrigR);
- TargetRegisterClass::iterator R = OrigR;
+ unsigned OrigR = RenameOrder[SuperRC];
+ unsigned EndR = ((OrigR == Order.size()) ? 0 : OrigR);
+ unsigned R = OrigR;
do {
- if (R == RB) R = RE;
+ if (R == 0) R = Order.size();
--R;
- const unsigned NewSuperReg = *R;
+ const unsigned NewSuperReg = Order[R];
+ // Don't consider non-allocatable registers
+ if (!MRI.isAllocatable(NewSuperReg)) continue;
// Don't replace a register with itself.
if (NewSuperReg == SuperReg) continue;
-
+
DEBUG(dbgs() << " [" << TRI->getName(NewSuperReg) << ':');
RenameMap.clear();
}
DEBUG(dbgs() << " " << TRI->getName(NewReg));
-
+
// Check if Reg can be renamed to NewReg.
BitVector BV = RenameRegisterMap[Reg];
if (!BV.test(NewReg)) {
goto next_super_reg;
} else {
bool found = false;
- for (const unsigned *Alias = TRI->getAliasSet(NewReg);
- *Alias; ++Alias) {
- unsigned AliasReg = *Alias;
- if (State->IsLive(AliasReg) || (KillIndices[Reg] > DefIndices[AliasReg])) {
+ for (MCRegAliasIterator AI(NewReg, TRI, false); AI.isValid(); ++AI) {
+ unsigned AliasReg = *AI;
+ if (State->IsLive(AliasReg) ||
+ (KillIndices[Reg] > DefIndices[AliasReg])) {
DEBUG(dbgs() << "(alias " << TRI->getName(AliasReg) << " live)");
found = true;
break;
if (found)
goto next_super_reg;
}
-
+
+ // We cannot rename 'Reg' to 'NewReg' if one of the uses of 'Reg' also
+ // defines 'NewReg' via an early-clobber operand.
+ for (const auto &Q : make_range(RegRefs.equal_range(Reg))) {
+ MachineInstr *UseMI = Q.second.Operand->getParent();
+ int Idx = UseMI->findRegisterDefOperandIdx(NewReg, false, true, TRI);
+ if (Idx == -1)
+ continue;
+
+ if (UseMI->getOperand(Idx).isEarlyClobber()) {
+ DEBUG(dbgs() << "(ec)");
+ goto next_super_reg;
+ }
+ }
+
+ // Also, we cannot rename 'Reg' to 'NewReg' if the instruction defining
+ // 'Reg' is an early-clobber define and that instruction also uses
+ // 'NewReg'.
+ for (const auto &Q : make_range(RegRefs.equal_range(Reg))) {
+ if (!Q.second.Operand->isDef() || !Q.second.Operand->isEarlyClobber())
+ continue;
+
+ MachineInstr *DefMI = Q.second.Operand->getParent();
+ if (DefMI->readsRegister(NewReg, TRI)) {
+ DEBUG(dbgs() << "(ec)");
+ goto next_super_reg;
+ }
+ }
+
// Record that 'Reg' can be renamed to 'NewReg'.
RenameMap.insert(std::pair<unsigned, unsigned>(Reg, NewReg));
}
-
+
// If we fall-out here, then every register in the group can be
// renamed, as recorded in RenameMap.
RenameOrder.erase(SuperRC);
/// ScheduleDAG and break them by renaming registers.
///
unsigned AggressiveAntiDepBreaker::BreakAntiDependencies(
- std::vector<SUnit>& SUnits,
- MachineBasicBlock::iterator& Begin,
- MachineBasicBlock::iterator& End,
- unsigned InsertPosIndex) {
- unsigned *KillIndices = State->GetKillIndices();
- unsigned *DefIndices = State->GetDefIndices();
- std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
+ const std::vector<SUnit>& SUnits,
+ MachineBasicBlock::iterator Begin,
+ MachineBasicBlock::iterator End,
+ unsigned InsertPosIndex,
+ DbgValueVector &DbgValues) {
+
+ std::vector<unsigned> &KillIndices = State->GetKillIndices();
+ std::vector<unsigned> &DefIndices = State->GetDefIndices();
+ std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
RegRefs = State->GetRegRefs();
// 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;
-
+
// For each regclass the next register to use for renaming.
RenameOrderType RenameOrder;
// ...need a map from MI to SUnit.
- std::map<MachineInstr *, SUnit *> MISUnitMap;
+ std::map<MachineInstr *, const SUnit *> MISUnitMap;
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
- SUnit *SU = &SUnits[i];
- MISUnitMap.insert(std::pair<MachineInstr *, SUnit *>(SU->getInstr(), SU));
+ const SUnit *SU = &SUnits[i];
+ MISUnitMap.insert(std::pair<MachineInstr *, const SUnit *>(SU->getInstr(),
+ SU));
}
// Track progress along the critical path through the SUnit graph as
// we walk the instructions. This is needed for regclasses that only
// break critical-path anti-dependencies.
- SUnit *CriticalPathSU = 0;
- MachineInstr *CriticalPathMI = 0;
+ const SUnit *CriticalPathSU = nullptr;
+ MachineInstr *CriticalPathMI = nullptr;
if (CriticalPathSet.any()) {
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
- SUnit *SU = &SUnits[i];
- if (!CriticalPathSU ||
- ((SU->getDepth() + SU->Latency) >
+ const SUnit *SU = &SUnits[i];
+ if (!CriticalPathSU ||
+ ((SU->getDepth() + SU->Latency) >
(CriticalPathSU->getDepth() + CriticalPathSU->Latency))) {
CriticalPathSU = SU;
}
}
-
+
CriticalPathMI = CriticalPathSU->getInstr();
}
-#ifndef NDEBUG
+#ifndef NDEBUG
DEBUG(dbgs() << "\n===== Aggressive anti-dependency breaking\n");
DEBUG(dbgs() << "Available regs:");
for (unsigned Reg = 0; Reg < TRI->getNumRegs(); ++Reg) {
I != E; --Count) {
MachineInstr *MI = --I;
+ if (MI->isDebugValue())
+ continue;
+
DEBUG(dbgs() << "Anti: ");
DEBUG(MI->dump());
// Process the defs in MI...
PrescanInstruction(MI, Count, PassthruRegs);
-
+
// The dependence edges that represent anti- and output-
// dependencies that are candidates for breaking.
- std::vector<SDep*> Edges;
- SUnit *PathSU = MISUnitMap[MI];
+ std::vector<const SDep *> Edges;
+ const SUnit *PathSU = MISUnitMap[MI];
AntiDepEdges(PathSU, Edges);
// If MI is not on the critical path, then we don't rename
// registers in the CriticalPathSet.
- BitVector *ExcludeRegs = NULL;
+ BitVector *ExcludeRegs = nullptr;
if (MI == CriticalPathMI) {
CriticalPathSU = CriticalPathStep(CriticalPathSU);
- CriticalPathMI = (CriticalPathSU) ? CriticalPathSU->getInstr() : 0;
- } else {
+ CriticalPathMI = (CriticalPathSU) ? CriticalPathSU->getInstr() : nullptr;
+ } else if (CriticalPathSet.any()) {
ExcludeRegs = &CriticalPathSet;
}
// Ignore KILL instructions (they form a group in ScanInstruction
// but don't cause any anti-dependence breaking themselves)
- if (MI->getOpcode() != TargetInstrInfo::KILL) {
+ if (!MI->isKill()) {
// Attempt to break each anti-dependency...
for (unsigned i = 0, e = Edges.size(); i != e; ++i) {
- SDep *Edge = Edges[i];
+ const SDep *Edge = Edges[i];
SUnit *NextSU = Edge->getSUnit();
-
+
if ((Edge->getKind() != SDep::Anti) &&
(Edge->getKind() != SDep::Output)) continue;
-
+
unsigned AntiDepReg = Edge->getReg();
DEBUG(dbgs() << "\tAntidep reg: " << TRI->getName(AntiDepReg));
assert(AntiDepReg != 0 && "Anti-dependence on reg0?");
-
- if (!AllocatableSet.test(AntiDepReg)) {
+
+ if (!MRI.isAllocatable(AntiDepReg)) {
// Don't break anti-dependencies on non-allocatable registers.
DEBUG(dbgs() << " (non-allocatable)\n");
continue;
- } else if ((ExcludeRegs != NULL) && ExcludeRegs->test(AntiDepReg)) {
+ } else if (ExcludeRegs && ExcludeRegs->test(AntiDepReg)) {
// Don't break anti-dependencies for critical path registers
// if not on the critical path
DEBUG(dbgs() << " (not critical-path)\n");
} else {
// No anti-dep breaking for implicit deps
MachineOperand *AntiDepOp = MI->findRegisterDefOperand(AntiDepReg);
- assert(AntiDepOp != NULL && "Can't find index for defined register operand");
- if ((AntiDepOp == NULL) || AntiDepOp->isImplicit()) {
+ assert(AntiDepOp && "Can't find index for defined register operand");
+ if (!AntiDepOp || AntiDepOp->isImplicit()) {
DEBUG(dbgs() << " (implicit)\n");
continue;
}
-
+
// If the SUnit has other dependencies on the SUnit that
// it anti-depends on, don't bother breaking the
// anti-dependency since those edges would prevent such
// Also, if there are dependencies on other SUnits with the
// same register as the anti-dependency, don't attempt to
// break it.
- for (SUnit::pred_iterator P = PathSU->Preds.begin(),
+ for (SUnit::const_pred_iterator P = PathSU->Preds.begin(),
PE = PathSU->Preds.end(); P != PE; ++P) {
if (P->getSUnit() == NextSU ?
(P->getKind() != SDep::Anti || P->getReg() != AntiDepReg) :
break;
}
}
- for (SUnit::pred_iterator P = PathSU->Preds.begin(),
+ for (SUnit::const_pred_iterator P = PathSU->Preds.begin(),
PE = PathSU->Preds.end(); P != PE; ++P) {
if ((P->getSUnit() == NextSU) && (P->getKind() != SDep::Anti) &&
(P->getKind() != SDep::Output)) {
DEBUG(dbgs() << " (real dependency)\n");
AntiDepReg = 0;
break;
- } else if ((P->getSUnit() != NextSU) &&
- (P->getKind() == SDep::Data) &&
+ } else if ((P->getSUnit() != NextSU) &&
+ (P->getKind() == SDep::Data) &&
(P->getReg() == AntiDepReg)) {
DEBUG(dbgs() << " (other dependency)\n");
AntiDepReg = 0;
break;
}
}
-
+
if (AntiDepReg == 0) continue;
}
-
+
assert(AntiDepReg != 0);
if (AntiDepReg == 0) continue;
-
+
// Determine AntiDepReg's register group.
const unsigned GroupIndex = State->GetGroup(AntiDepReg);
if (GroupIndex == 0) {
DEBUG(dbgs() << " (zero group)\n");
continue;
}
-
+
DEBUG(dbgs() << '\n');
-
+
// Look for a suitable register to use to break the anti-dependence.
std::map<unsigned, unsigned> RenameMap;
if (FindSuitableFreeRegisters(GroupIndex, RenameOrder, RenameMap)) {
DEBUG(dbgs() << "\tBreaking anti-dependence edge on "
<< TRI->getName(AntiDepReg) << ":");
-
+
// Handle each group register...
for (std::map<unsigned, unsigned>::iterator
S = RenameMap.begin(), E = RenameMap.end(); S != E; ++S) {
unsigned CurrReg = S->first;
unsigned NewReg = S->second;
-
- DEBUG(dbgs() << " " << TRI->getName(CurrReg) << "->" <<
- TRI->getName(NewReg) << "(" <<
+
+ DEBUG(dbgs() << " " << TRI->getName(CurrReg) << "->" <<
+ TRI->getName(NewReg) << "(" <<
RegRefs.count(CurrReg) << " refs)");
-
+
// Update the references to the old register CurrReg to
// refer to the new register NewReg.
- std::pair<std::multimap<unsigned,
- AggressiveAntiDepState::RegisterReference>::iterator,
- std::multimap<unsigned,
- AggressiveAntiDepState::RegisterReference>::iterator>
- Range = RegRefs.equal_range(CurrReg);
- for (std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>::iterator
- Q = Range.first, QE = Range.second; Q != QE; ++Q) {
- Q->second.Operand->setReg(NewReg);
+ for (const auto &Q : make_range(RegRefs.equal_range(CurrReg))) {
+ Q.second.Operand->setReg(NewReg);
+ // If the SU for the instruction being updated has debug
+ // information related to the anti-dependency register, make
+ // sure to update that as well.
+ const SUnit *SU = MISUnitMap[Q.second.Operand->getParent()];
+ if (!SU) continue;
+ for (DbgValueVector::iterator DVI = DbgValues.begin(),
+ DVE = DbgValues.end(); DVI != DVE; ++DVI)
+ if (DVI->second == Q.second.Operand->getParent())
+ UpdateDbgValue(DVI->first, AntiDepReg, NewReg);
}
-
+
// We just went back in time and modified history; the
// liveness information for CurrReg is now inconsistent. Set
// the state as if it were dead.
RegRefs.erase(NewReg);
DefIndices[NewReg] = DefIndices[CurrReg];
KillIndices[NewReg] = KillIndices[CurrReg];
-
+
State->UnionGroups(CurrReg, 0);
RegRefs.erase(CurrReg);
DefIndices[CurrReg] = KillIndices[CurrReg];
(DefIndices[CurrReg] == ~0u)) &&
"Kill and Def maps aren't consistent for AntiDepReg!");
}
-
+
++Broken;
DEBUG(dbgs() << '\n');
}
ScanInstruction(MI, Count);
}
-
+
return Broken;
}