#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"
+#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
#define DEBUG_TYPE "post-RA-sched"
-CriticalAntiDepBreaker::
-CriticalAntiDepBreaker(MachineFunction& MFi, const RegisterClassInfo &RCI) :
- AntiDepBreaker(), MF(MFi),
- MRI(MF.getRegInfo()),
- TII(MF.getTarget().getInstrInfo()),
- TRI(MF.getTarget().getRegisterInfo()),
- RegClassInfo(RCI),
- Classes(TRI->getNumRegs(), nullptr),
- KillIndices(TRI->getNumRegs(), 0),
- DefIndices(TRI->getNumRegs(), 0),
- KeepRegs(TRI->getNumRegs(), false) {}
+CriticalAntiDepBreaker::CriticalAntiDepBreaker(MachineFunction &MFi,
+ const RegisterClassInfo &RCI)
+ : AntiDepBreaker(), MF(MFi), MRI(MF.getRegInfo()),
+ TII(MF.getSubtarget().getInstrInfo()),
+ TRI(MF.getSubtarget().getRegisterInfo()), RegClassInfo(RCI),
+ Classes(TRI->getNumRegs(), nullptr), KillIndices(TRI->getNumRegs(), 0),
+ DefIndices(TRI->getNumRegs(), 0), KeepRegs(TRI->getNumRegs(), false) {}
CriticalAntiDepBreaker::~CriticalAntiDepBreaker() {
}
void CriticalAntiDepBreaker::Observe(MachineInstr *MI, unsigned Count,
unsigned InsertPosIndex) {
- if (MI->isDebugValue())
+ // Kill instructions can define registers but are really nops, and there might
+ // be a real definition earlier that needs to be paired with uses dominated by
+ // this kill.
+
+ // FIXME: It may be possible to remove the isKill() restriction once PR18663
+ // has been properly fixed. There can be value in processing kills as seen in
+ // the AggressiveAntiDepBreaker class.
+ if (MI->isDebugValue() || MI->isKill())
return;
assert(Count < InsertPosIndex && "Instruction index out of expected range!");
// Update liveness.
// Proceeding upwards, registers that are defed but not used in this
// instruction are now dead.
+ assert(!MI->isKill() && "Attempting to scan a kill instruction");
if (!TII->isPredicated(MI)) {
// Predicated defs are modeled as read + write, i.e. similar to two
// Ignore two-addr defs.
if (MI->isRegTiedToUseOperand(i)) continue;
- // FIXME: we should use a SubRegIterator that includes self (as above), so
- // we don't have to repeat all this code for the reg itself.
- DefIndices[Reg] = Count;
- KillIndices[Reg] = ~0u;
- assert(((KillIndices[Reg] == ~0u) !=
- (DefIndices[Reg] == ~0u)) &&
- "Kill and Def maps aren't consistent for Reg!");
- KeepRegs.reset(Reg);
- Classes[Reg] = nullptr;
- RegRefs.erase(Reg);
- // Repeat, for all subregs.
- for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
- unsigned SubregReg = *SubRegs;
+ // For the reg itself and all subregs: update the def to current;
+ // reset the kill state, any restrictions, and references.
+ for (MCSubRegIterator SRI(Reg, TRI, true); SRI.isValid(); ++SRI) {
+ unsigned SubregReg = *SRI;
DefIndices[SubregReg] = Count;
KillIndices[SubregReg] = ~0u;
KeepRegs.reset(SubregReg);
RegRefs.insert(std::make_pair(Reg, &MO));
- // FIXME: we should use an MCRegAliasIterator that includes self so we don't
- // have to repeat all this code for the reg itself.
-
// It wasn't previously live but now it is, this is a kill.
- if (KillIndices[Reg] == ~0u) {
- KillIndices[Reg] = Count;
- DefIndices[Reg] = ~0u;
- assert(((KillIndices[Reg] == ~0u) !=
- (DefIndices[Reg] == ~0u)) &&
- "Kill and Def maps aren't consistent for Reg!");
- }
- // Repeat, for all aliases.
- for (MCRegAliasIterator AI(Reg, TRI, false); AI.isValid(); ++AI) {
+ // Repeat for all aliases.
+ for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
unsigned AliasReg = *AI;
if (KillIndices[AliasReg] == ~0u) {
KillIndices[AliasReg] = Count;
unsigned Count = InsertPosIndex - 1;
for (MachineBasicBlock::iterator I = End, E = Begin; I != E; --Count) {
MachineInstr *MI = --I;
- if (MI->isDebugValue())
+ // Kill instructions can define registers but are really nops, and there
+ // might be a real definition earlier that needs to be paired with uses
+ // dominated by this kill.
+
+ // FIXME: It may be possible to remove the isKill() restriction once PR18663
+ // has been properly fixed. There can be value in processing kills as seen
+ // in the AggressiveAntiDepBreaker class.
+ if (MI->isDebugValue() || MI->isKill())
continue;
// Check if this instruction has a dependence on the critical path that