int FrameIdx = 0;
if (tii_->isLoadFromStackSlot(MI, FrameIdx) &&
- mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx)) {
- // This is a load from fixed stack slot. It can be rematerialized unless
- // it's re-defined by a two-address instruction.
- isLoad = true;
- for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
- i != e; ++i) {
- const VNInfo *VNI = *i;
- if (VNI == ValNo)
- continue;
- unsigned DefIdx = VNI->def;
- if (DefIdx == ~1U)
- continue; // Dead val#.
- MachineInstr *DefMI = (DefIdx == ~0u)
- ? NULL : getInstructionFromIndex(DefIdx);
- if (DefMI && DefMI->isRegReDefinedByTwoAddr(li.reg)) {
- isLoad = false;
- return false;
- }
- }
+ mf_->getFrameInfo()->isImmutableObjectIndex(FrameIdx))
+ // FIXME: Let target specific isReallyTriviallyReMaterializable determines
+ // this but remember this is not safe to fold into a two-address
+ // instruction.
+ // This is a load from fixed stack slot. It can be rematerialized.
return true;
- }
if (tii_->isTriviallyReMaterializable(MI)) {
isLoad = TID.isSimpleLoad();
return true;
}
-/// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
-/// slot / to reg or any rematerialized load into ith operand of specified
-/// MI. If it is successul, MI is updated with the newly created MI and
-/// returns true.
-bool LiveIntervals::tryFoldMemoryOperand(MachineInstr* &MI,
- VirtRegMap &vrm, MachineInstr *DefMI,
- unsigned InstrIdx,
- SmallVector<unsigned, 2> &Ops,
- bool isSS, int Slot, unsigned Reg) {
- unsigned MRInfo = 0;
+/// FilterFoldedOps - Filter out two-address use operands. Return
+/// true if it finds any issue with the operands that ought to prevent
+/// folding.
+static bool FilterFoldedOps(MachineInstr *MI,
+ SmallVector<unsigned, 2> &Ops,
+ unsigned &MRInfo,
+ SmallVector<unsigned, 2> &FoldOps) {
const TargetInstrDesc &TID = MI->getDesc();
- // If it is an implicit def instruction, just delete it.
- if (TID.isImplicitDef()) {
- RemoveMachineInstrFromMaps(MI);
- vrm.RemoveMachineInstrFromMaps(MI);
- MI->eraseFromParent();
- ++numFolds;
- return true;
- }
- SmallVector<unsigned, 2> FoldOps;
+ MRInfo = 0;
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
unsigned OpIdx = Ops[i];
MachineOperand &MO = MI->getOperand(OpIdx);
// FIXME: fold subreg use.
if (MO.getSubReg())
- return false;
+ return true;
if (MO.isDef())
MRInfo |= (unsigned)VirtRegMap::isMod;
else {
}
FoldOps.push_back(OpIdx);
}
+ return false;
+}
+
+
+/// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
+/// slot / to reg or any rematerialized load into ith operand of specified
+/// MI. If it is successul, MI is updated with the newly created MI and
+/// returns true.
+bool LiveIntervals::tryFoldMemoryOperand(MachineInstr* &MI,
+ VirtRegMap &vrm, MachineInstr *DefMI,
+ unsigned InstrIdx,
+ SmallVector<unsigned, 2> &Ops,
+ bool isSS, int Slot, unsigned Reg) {
+ const TargetInstrDesc &TID = MI->getDesc();
+ // If it is an implicit def instruction, just delete it.
+ if (TID.isImplicitDef()) {
+ RemoveMachineInstrFromMaps(MI);
+ vrm.RemoveMachineInstrFromMaps(MI);
+ MI->eraseFromParent();
+ ++numFolds;
+ return true;
+ }
+
+ // Filter the list of operand indexes that are to be folded. Abort if
+ // any operand will prevent folding.
+ unsigned MRInfo = 0;
+ SmallVector<unsigned, 2> FoldOps;
+ if (FilterFoldedOps(MI, Ops, MRInfo, FoldOps))
+ return false;
+
+ // Can't fold a load from fixed stack slot into a two address instruction.
+ if (isSS && DefMI && (MRInfo & VirtRegMap::isMod))
+ return false;
MachineInstr *fmi = isSS ? tii_->foldMemoryOperand(*mf_, MI, FoldOps, Slot)
: tii_->foldMemoryOperand(*mf_, MI, FoldOps, DefMI);
if (fmi) {
+ // Remember this instruction uses the spill slot.
+ if (isSS) vrm.addSpillSlotUse(Slot, fmi);
+
// Attempt to fold the memory reference into the instruction. If
// we can do this, we don't need to insert spill code.
if (lv_)
/// canFoldMemoryOperand - Returns true if the specified load / store
/// folding is possible.
bool LiveIntervals::canFoldMemoryOperand(MachineInstr *MI,
- SmallVector<unsigned, 2> &Ops) const {
+ SmallVector<unsigned, 2> &Ops,
+ bool ReMatLoad) const {
+ // Filter the list of operand indexes that are to be folded. Abort if
+ // any operand will prevent folding.
+ unsigned MRInfo = 0;
SmallVector<unsigned, 2> FoldOps;
- for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
- unsigned OpIdx = Ops[i];
- // FIXME: fold subreg use.
- if (MI->getOperand(OpIdx).getSubReg())
- return false;
- FoldOps.push_back(OpIdx);
- }
+ if (FilterFoldedOps(MI, Ops, MRInfo, FoldOps))
+ return false;
- return tii_->canFoldMemoryOperand(MI, FoldOps);
-}
+ // Can't fold a remat'ed load into a two address instruction.
+ if (ReMatLoad && (MRInfo & VirtRegMap::isMod))
+ return false;
-bool LiveIntervals::canFoldMemoryOperand(MachineInstr *MI, unsigned Reg) const {
- SmallVector<unsigned, 2> FoldOps;
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand& mop = MI->getOperand(i);
- if (!mop.isRegister())
- continue;
- unsigned UseReg = mop.getReg();
- if (UseReg != Reg)
- continue;
- // FIXME: fold subreg use.
- if (mop.getSubReg())
- return false;
- FoldOps.push_back(i);
- }
return tii_->canFoldMemoryOperand(MI, FoldOps);
}
goto RestartInstruction;
}
} else {
- CanFold = canFoldMemoryOperand(MI, Ops);
+ CanFold = canFoldMemoryOperand(MI, Ops, DefIsReMat && isLoad);
}
} else
CanFold = false;
projects / oota-llvm.git / blobdiff