//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "post-RA-sched"
#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;
+#define DEBUG_TYPE "post-RA-sched"
+
CriticalAntiDepBreaker::
CriticalAntiDepBreaker(MachineFunction& MFi, const RegisterClassInfo &RCI) :
AntiDepBreaker(), MF(MFi),
TII(MF.getTarget().getInstrInfo()),
TRI(MF.getTarget().getRegisterInfo()),
RegClassInfo(RCI),
- Classes(TRI->getNumRegs(), static_cast<const TargetRegisterClass *>(0)),
+ Classes(TRI->getNumRegs(), nullptr),
KillIndices(TRI->getNumRegs(), 0),
DefIndices(TRI->getNumRegs(), 0),
KeepRegs(TRI->getNumRegs(), false) {}
const unsigned BBSize = BB->size();
for (unsigned i = 0, e = TRI->getNumRegs(); i != e; ++i) {
// Clear out the register class data.
- Classes[i] = static_cast<const TargetRegisterClass *>(0);
+ Classes[i] = nullptr;
// Initialize the indices to indicate that no registers are live.
KillIndices[i] = ~0u;
bool IsReturnBlock = (BBSize != 0 && BB->back().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) {
- for (MCRegAliasIterator AI(*I, TRI, true); AI.isValid(); ++AI) {
- unsigned Reg = *AI;
- Classes[Reg] = reinterpret_cast<TargetRegisterClass *>(-1);
- KillIndices[Reg] = BBSize;
- DefIndices[Reg] = ~0u;
- }
- }
- }
-
- // 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(),
// callee-saved register that is not saved in the prolog.
const MachineFrameInfo *MFI = MF.getFrameInfo();
BitVector Pristine = MFI->getPristineRegs(BB);
- for (const uint16_t *I = TRI->getCalleeSavedRegs(&MF); *I; ++I) {
+ for (const MCPhysReg *I = TRI->getCalleeSavedRegs(&MF); *I; ++I) {
if (!IsReturnBlock && !Pristine.test(*I)) continue;
for (MCRegAliasIterator AI(*I, TRI, true); AI.isValid(); ++AI) {
unsigned Reg = *AI;
/// CriticalPathStep - Return the next SUnit after SU on the bottom-up
/// critical path.
static const SDep *CriticalPathStep(const SUnit *SU) {
- const SDep *Next = 0;
+ const SDep *Next = nullptr;
unsigned NextDepth = 0;
// Find the predecessor edge with the greatest depth.
for (SUnit::const_pred_iterator P = SU->Preds.begin(), PE = SU->Preds.end();
if (!MO.isReg()) continue;
unsigned Reg = MO.getReg();
if (Reg == 0) continue;
- const TargetRegisterClass *NewRC = 0;
+ const TargetRegisterClass *NewRC = nullptr;
if (i < MI->getDesc().getNumOperands())
NewRC = TII->getRegClass(MI->getDesc(), i, TRI, MF);
if (MO.isUse() && Special) {
if (!KeepRegs.test(Reg)) {
- KeepRegs.set(Reg);
- for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+ for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
+ SubRegs.isValid(); ++SubRegs)
KeepRegs.set(*SubRegs);
}
}
DefIndices[i] = Count;
KillIndices[i] = ~0u;
KeepRegs.reset(i);
- Classes[i] = 0;
+ Classes[i] = nullptr;
RegRefs.erase(i);
}
(DefIndices[Reg] == ~0u)) &&
"Kill and Def maps aren't consistent for Reg!");
KeepRegs.reset(Reg);
- Classes[Reg] = 0;
+ Classes[Reg] = nullptr;
RegRefs.erase(Reg);
// Repeat, for all subregs.
for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
DefIndices[SubregReg] = Count;
KillIndices[SubregReg] = ~0u;
KeepRegs.reset(SubregReg);
- Classes[SubregReg] = 0;
+ Classes[SubregReg] = nullptr;
RegRefs.erase(SubregReg);
}
// Conservatively mark super-registers as unusable.
if (Reg == 0) continue;
if (!MO.isUse()) continue;
- const TargetRegisterClass *NewRC = 0;
+ const TargetRegisterClass *NewRC = nullptr;
if (i < MI->getDesc().getNumOperands())
NewRC = TII->getRegClass(MI->getDesc(), i, TRI, MF);
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<unsigned> &Forbid)
{
- ArrayRef<unsigned> Order = RegClassInfo.getOrder(RC);
+ ArrayRef<MCPhysReg> Order = RegClassInfo.getOrder(RC);
for (unsigned i = 0; i != Order.size(); ++i) {
unsigned NewReg = Order[i];
// Don't replace a register with itself.
Classes[NewReg] == reinterpret_cast<TargetRegisterClass *>(-1) ||
KillIndices[AntiDepReg] > DefIndices[NewReg])
continue;
+ // If NewReg overlaps any of the forbidden registers, we can't use it.
+ bool Forbidden = false;
+ for (SmallVectorImpl<unsigned>::iterator it = Forbid.begin(),
+ ite = Forbid.end(); it != ite; ++it)
+ if (TRI->regsOverlap(NewReg, *it)) {
+ Forbidden = true;
+ break;
+ }
+ if (Forbidden) continue;
return NewReg;
}
DenseMap<MachineInstr*,const SUnit*> MISUnitMap;
// Find the node at the bottom of the critical path.
- const SUnit *Max = 0;
+ const SUnit *Max = nullptr;
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
const SUnit *SU = &SUnits[i];
MISUnitMap[SU->getInstr()] = SU;
CriticalPathMI = CriticalPathSU->getInstr();
} else {
// We've reached the end of the critical path.
- CriticalPathSU = 0;
- CriticalPathMI = 0;
+ CriticalPathSU = nullptr;
+ CriticalPathMI = nullptr;
}
}
PrescanInstruction(MI);
+ SmallVector<unsigned, 2> 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).
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;
AntiDepReg = 0;
break;
}
+ if (MO.isDef() && Reg != AntiDepReg)
+ ForbidRegs.push_back(Reg);
}
}
// Determine AntiDepReg's register class, if it is live and is
// consistently used within a single class.
- const TargetRegisterClass *RC = AntiDepReg != 0 ? Classes[AntiDepReg] : 0;
- assert((AntiDepReg == 0 || RC != NULL) &&
+ const TargetRegisterClass *RC = AntiDepReg != 0 ? Classes[AntiDepReg]
+ : nullptr;
+ assert((AntiDepReg == 0 || RC != nullptr) &&
"Register should be live if it's causing an anti-dependence!");
if (RC == reinterpret_cast<TargetRegisterClass *>(-1))
AntiDepReg = 0;
- // Look for a suitable register to use to break the anti-depenence.
+ // Look for a suitable register to use to break the anti-dependence.
//
// TODO: Instead of picking the first free register, consider which might
// be the best.
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"
(DefIndices[NewReg] == ~0u)) &&
"Kill and Def maps aren't consistent for NewReg!");
- Classes[AntiDepReg] = 0;
+ Classes[AntiDepReg] = nullptr;
DefIndices[AntiDepReg] = KillIndices[AntiDepReg];
KillIndices[AntiDepReg] = ~0u;
assert(((KillIndices[AntiDepReg] == ~0u) !=
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