// is spilled or split.
//===----------------------------------------------------------------------===//
+#define DEBUG_TYPE "regalloc"
#include "LiveRangeEdit.h"
#include "VirtRegMap.h"
#include "llvm/ADT/SetVector.h"
+#include "llvm/CodeGen/CalcSpillWeights.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
return LI;
}
+void LiveRangeEdit::checkRematerializable(VNInfo *VNI,
+ const MachineInstr *DefMI,
+ const TargetInstrInfo &tii,
+ AliasAnalysis *aa) {
+ assert(DefMI && "Missing instruction");
+ if (tii.isTriviallyReMaterializable(DefMI, aa))
+ remattable_.insert(VNI);
+ scannedRemattable_ = true;
+}
+
void LiveRangeEdit::scanRemattable(LiveIntervals &lis,
const TargetInstrInfo &tii,
AliasAnalysis *aa) {
MachineInstr *DefMI = lis.getInstructionFromIndex(VNI->def);
if (!DefMI)
continue;
- if (tii.isTriviallyReMaterializable(DefMI, aa))
- remattable_.insert(VNI);
+ checkRematerializable(VNI, DefMI, tii, aa);
}
- scannedRemattable_ = true;
}
bool LiveRangeEdit::anyRematerializable(LiveIntervals &lis,
UseIdx = UseIdx.getUseIndex();
for (unsigned i = 0, e = OrigMI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = OrigMI->getOperand(i);
- if (!MO.isReg() || !MO.getReg() || MO.getReg() == getReg())
+ if (!MO.isReg() || !MO.getReg() || MO.isDef())
continue;
// Reserved registers are OK.
if (MO.isUndef() || !lis.hasInterval(MO.getReg()))
continue;
- // We don't want to move any defs.
- if (MO.isDef())
- return false;
// We cannot depend on virtual registers in uselessRegs_.
if (uselessRegs_)
for (unsigned ui = 0, ue = uselessRegs_->size(); ui != ue; ++ui)
if (!remattable_.count(RM.ParentVNI))
return false;
- // No defining instruction.
- RM.OrigMI = lis.getInstructionFromIndex(RM.ParentVNI->def);
- assert(RM.OrigMI && "Defining instruction for remattable value disappeared");
+ // No defining instruction provided.
+ SlotIndex DefIdx;
+ if (RM.OrigMI)
+ DefIdx = lis.getInstructionIndex(RM.OrigMI);
+ else {
+ DefIdx = RM.ParentVNI->def;
+ RM.OrigMI = lis.getInstructionFromIndex(DefIdx);
+ assert(RM.OrigMI && "No defining instruction for remattable value");
+ }
// If only cheap remats were requested, bail out early.
if (cheapAsAMove && !RM.OrigMI->getDesc().isAsCheapAsAMove())
return false;
// Verify that all used registers are available with the same values.
- if (!allUsesAvailableAt(RM.OrigMI, RM.ParentVNI->def, UseIdx, lis))
+ if (!allUsesAvailableAt(RM.OrigMI, DefIdx, UseIdx, lis))
return false;
return true;
LIS.removeInterval(Reg);
}
+bool LiveRangeEdit::foldAsLoad(LiveInterval *LI,
+ SmallVectorImpl<MachineInstr*> &Dead,
+ MachineRegisterInfo &MRI,
+ LiveIntervals &LIS,
+ const TargetInstrInfo &TII) {
+ MachineInstr *DefMI = 0, *UseMI = 0;
+
+ // Check that there is a single def and a single use.
+ for (MachineRegisterInfo::reg_nodbg_iterator I = MRI.reg_nodbg_begin(LI->reg),
+ E = MRI.reg_nodbg_end(); I != E; ++I) {
+ MachineOperand &MO = I.getOperand();
+ MachineInstr *MI = MO.getParent();
+ if (MO.isDef()) {
+ if (DefMI && DefMI != MI)
+ return false;
+ if (!MI->getDesc().canFoldAsLoad())
+ return false;
+ DefMI = MI;
+ } else if (!MO.isUndef()) {
+ if (UseMI && UseMI != MI)
+ return false;
+ // FIXME: Targets don't know how to fold subreg uses.
+ if (MO.getSubReg())
+ return false;
+ UseMI = MI;
+ }
+ }
+ if (!DefMI || !UseMI)
+ return false;
+
+ DEBUG(dbgs() << "Try to fold single def: " << *DefMI
+ << " into single use: " << *UseMI);
+
+ SmallVector<unsigned, 8> Ops;
+ if (UseMI->readsWritesVirtualRegister(LI->reg, &Ops).second)
+ return false;
+
+ MachineInstr *FoldMI = TII.foldMemoryOperand(UseMI, Ops, DefMI);
+ if (!FoldMI)
+ return false;
+ DEBUG(dbgs() << " folded: " << *FoldMI);
+ LIS.ReplaceMachineInstrInMaps(UseMI, FoldMI);
+ UseMI->eraseFromParent();
+ DefMI->addRegisterDead(LI->reg, 0);
+ Dead.push_back(DefMI);
+ return true;
+}
+
void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
LiveIntervals &LIS, VirtRegMap &VRM,
const TargetInstrInfo &TII) {
SetVector<LiveInterval*,
SmallVector<LiveInterval*, 8>,
SmallPtrSet<LiveInterval*, 8> > ToShrink;
+ MachineRegisterInfo &MRI = VRM.getRegInfo();
for (;;) {
// Erase all dead defs.
continue;
LiveInterval &LI = LIS.getInterval(Reg);
- // Shrink read registers.
- if (MI->readsVirtualRegister(Reg))
+ // Shrink read registers, unless it is likely to be expensive and
+ // unlikely to change anything. We typically don't want to shrink the
+ // PIC base register that has lots of uses everywhere.
+ // Always shrink COPY uses that probably come from live range splitting.
+ if (MI->readsVirtualRegister(Reg) &&
+ (MI->isCopy() || MOI->isDef() || MRI.hasOneNonDBGUse(Reg) ||
+ LI.killedAt(Idx)))
ToShrink.insert(&LI);
// Remove defined value.
if (MOI->isDef()) {
if (VNInfo *VNI = LI.getVNInfoAt(Idx)) {
+ if (delegate_)
+ delegate_->LRE_WillShrinkVirtReg(LI.reg);
LI.removeValNo(VNI);
if (LI.empty()) {
ToShrink.remove(&LI);
// Shrink just one live interval. Then delete new dead defs.
LiveInterval *LI = ToShrink.back();
ToShrink.pop_back();
+ if (foldAsLoad(LI, Dead, MRI, LIS, TII))
+ continue;
if (delegate_)
delegate_->LRE_WillShrinkVirtReg(LI->reg);
if (!LIS.shrinkToUses(LI, &Dead))
continue;
DEBUG(dbgs() << NumComp << " components: " << *LI << '\n');
SmallVector<LiveInterval*, 8> Dups(1, LI);
- for (unsigned i = 1; i != NumComp; ++i)
+ for (unsigned i = 1; i != NumComp; ++i) {
Dups.push_back(&createFrom(LI->reg, LIS, VRM));
- ConEQ.Distribute(&Dups[0], VRM.getRegInfo());
+ if (delegate_)
+ delegate_->LRE_DidCloneVirtReg(Dups.back()->reg, LI->reg);
+ }
+ ConEQ.Distribute(&Dups[0], MRI);
}
}
+void LiveRangeEdit::calculateRegClassAndHint(MachineFunction &MF,
+ LiveIntervals &LIS,
+ const MachineLoopInfo &Loops) {
+ VirtRegAuxInfo VRAI(MF, LIS, Loops);
+ for (iterator I = begin(), E = end(); I != E; ++I) {
+ LiveInterval &LI = **I;
+ VRAI.CalculateRegClass(LI.reg);
+ VRAI.CalculateWeightAndHint(LI);
+ }
+}
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