//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "spiller"
+#define DEBUG_TYPE "regalloc"
#include "Spiller.h"
-#include "SplitKit.h"
+#include "LiveRangeEdit.h"
#include "VirtRegMap.h"
+#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/LiveStackAnalysis.h"
+#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
namespace {
class InlineSpiller : public Spiller {
- MachineFunctionPass &pass_;
- MachineFunction &mf_;
- LiveIntervals &lis_;
- MachineLoopInfo &loops_;
- VirtRegMap &vrm_;
- MachineFrameInfo &mfi_;
- MachineRegisterInfo &mri_;
- const TargetInstrInfo &tii_;
- const TargetRegisterInfo &tri_;
- const BitVector reserved_;
-
- SplitAnalysis splitAnalysis_;
+ MachineFunctionPass &Pass;
+ MachineFunction &MF;
+ LiveIntervals &LIS;
+ LiveStacks &LSS;
+ AliasAnalysis *AA;
+ MachineDominatorTree &MDT;
+ MachineLoopInfo &Loops;
+ VirtRegMap &VRM;
+ MachineFrameInfo &MFI;
+ MachineRegisterInfo &MRI;
+ const TargetInstrInfo &TII;
+ const TargetRegisterInfo &TRI;
// Variables that are valid during spill(), but used by multiple methods.
- LiveInterval *li_;
- SmallVectorImpl<LiveInterval*> *newIntervals_;
- const TargetRegisterClass *rc_;
- int stackSlot_;
- const SmallVectorImpl<LiveInterval*> *spillIs_;
+ LiveRangeEdit *Edit;
+ LiveInterval *StackInt;
+ int StackSlot;
+ unsigned Original;
- // Values of the current interval that can potentially remat.
- SmallPtrSet<VNInfo*, 8> reMattable_;
+ // All registers to spill to StackSlot, including the main register.
+ SmallVector<unsigned, 8> RegsToSpill;
- // Values in reMattable_ that failed to remat at some point.
- SmallPtrSet<VNInfo*, 8> usedValues_;
+ // All COPY instructions to/from snippets.
+ // They are ignored since both operands refer to the same stack slot.
+ SmallPtrSet<MachineInstr*, 8> SnippetCopies;
+
+ // Values that failed to remat at some point.
+ SmallPtrSet<VNInfo*, 8> UsedValues;
+
+ // Information about a value that was defined by a copy from a sibling
+ // register.
+ struct SibValueInfo {
+ // True when all reaching defs were reloads: No spill is necessary.
+ bool AllDefsAreReloads;
+
+ // The preferred register to spill.
+ unsigned SpillReg;
+
+ // The value of SpillReg that should be spilled.
+ VNInfo *SpillVNI;
+
+ // A defining instruction that is not a sibling copy or a reload, or NULL.
+ // This can be used as a template for rematerialization.
+ MachineInstr *DefMI;
+
+ SibValueInfo(unsigned Reg, VNInfo *VNI)
+ : AllDefsAreReloads(false), SpillReg(Reg), SpillVNI(VNI), DefMI(0) {}
+ };
+
+ // Values in RegsToSpill defined by sibling copies.
+ typedef DenseMap<VNInfo*, SibValueInfo> SibValueMap;
+ SibValueMap SibValues;
+
+ // Dead defs generated during spilling.
+ SmallVector<MachineInstr*, 8> DeadDefs;
~InlineSpiller() {}
InlineSpiller(MachineFunctionPass &pass,
MachineFunction &mf,
VirtRegMap &vrm)
- : pass_(pass),
- mf_(mf),
- lis_(pass.getAnalysis<LiveIntervals>()),
- loops_(pass.getAnalysis<MachineLoopInfo>()),
- vrm_(vrm),
- mfi_(*mf.getFrameInfo()),
- mri_(mf.getRegInfo()),
- tii_(*mf.getTarget().getInstrInfo()),
- tri_(*mf.getTarget().getRegisterInfo()),
- reserved_(tri_.getReservedRegs(mf_)),
- splitAnalysis_(mf, lis_, loops_) {}
-
- void spill(LiveInterval *li,
- SmallVectorImpl<LiveInterval*> &newIntervals,
- SmallVectorImpl<LiveInterval*> &spillIs);
+ : Pass(pass),
+ MF(mf),
+ LIS(pass.getAnalysis<LiveIntervals>()),
+ LSS(pass.getAnalysis<LiveStacks>()),
+ AA(&pass.getAnalysis<AliasAnalysis>()),
+ MDT(pass.getAnalysis<MachineDominatorTree>()),
+ Loops(pass.getAnalysis<MachineLoopInfo>()),
+ VRM(vrm),
+ MFI(*mf.getFrameInfo()),
+ MRI(mf.getRegInfo()),
+ TII(*mf.getTarget().getInstrInfo()),
+ TRI(*mf.getTarget().getRegisterInfo()) {}
+
+ void spill(LiveRangeEdit &);
private:
- bool split();
+ bool isSnippet(const LiveInterval &SnipLI);
+ void collectRegsToSpill();
+
+ bool isRegToSpill(unsigned Reg) {
+ return std::find(RegsToSpill.begin(),
+ RegsToSpill.end(), Reg) != RegsToSpill.end();
+ }
+
+ bool isSibling(unsigned Reg);
+ MachineInstr *traceSiblingValue(unsigned, VNInfo*, VNInfo*);
+ void analyzeSiblingValues();
- bool allUsesAvailableAt(const MachineInstr *OrigMI, SlotIndex OrigIdx,
- SlotIndex UseIdx);
- bool reMaterializeFor(MachineBasicBlock::iterator MI);
+ bool hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI);
+ void eliminateRedundantSpills(LiveInterval &LI, VNInfo *VNI);
+
+ void markValueUsed(LiveInterval*, VNInfo*);
+ bool reMaterializeFor(LiveInterval&, MachineBasicBlock::iterator MI);
void reMaterializeAll();
- bool coalesceStackAccess(MachineInstr *MI);
+ bool coalesceStackAccess(MachineInstr *MI, unsigned Reg);
bool foldMemoryOperand(MachineBasicBlock::iterator MI,
- const SmallVectorImpl<unsigned> &Ops);
- void insertReload(LiveInterval &NewLI, MachineBasicBlock::iterator MI);
- void insertSpill(LiveInterval &NewLI, MachineBasicBlock::iterator MI);
+ const SmallVectorImpl<unsigned> &Ops,
+ MachineInstr *LoadMI = 0);
+ void insertReload(LiveInterval &NewLI, SlotIndex,
+ MachineBasicBlock::iterator MI);
+ void insertSpill(LiveInterval &NewLI, const LiveInterval &OldLI,
+ SlotIndex, MachineBasicBlock::iterator MI);
+
+ void spillAroundUses(unsigned Reg);
+ void spillAll();
};
}
}
}
-/// split - try splitting the current interval into pieces that may allocate
-/// separately. Return true if successful.
-bool InlineSpiller::split() {
- splitAnalysis_.analyze(li_);
+//===----------------------------------------------------------------------===//
+// Snippets
+//===----------------------------------------------------------------------===//
- if (const MachineLoop *loop = splitAnalysis_.getBestSplitLoop()) {
- // We can split, but li_ may be left intact with fewer uses.
- if (SplitEditor(splitAnalysis_, lis_, vrm_, *newIntervals_)
- .splitAroundLoop(loop))
- return true;
- }
+// When spilling a virtual register, we also spill any snippets it is connected
+// to. The snippets are small live ranges that only have a single real use,
+// leftovers from live range splitting. Spilling them enables memory operand
+// folding or tightens the live range around the single use.
+//
+// This minimizes register pressure and maximizes the store-to-load distance for
+// spill slots which can be important in tight loops.
+
+/// isFullCopyOf - If MI is a COPY to or from Reg, return the other register,
+/// otherwise return 0.
+static unsigned isFullCopyOf(const MachineInstr *MI, unsigned Reg) {
+ if (!MI->isCopy())
+ return 0;
+ if (MI->getOperand(0).getSubReg() != 0)
+ return 0;
+ if (MI->getOperand(1).getSubReg() != 0)
+ return 0;
+ if (MI->getOperand(0).getReg() == Reg)
+ return MI->getOperand(1).getReg();
+ if (MI->getOperand(1).getReg() == Reg)
+ return MI->getOperand(0).getReg();
+ return 0;
+}
+
+/// isSnippet - Identify if a live interval is a snippet that should be spilled.
+/// It is assumed that SnipLI is a virtual register with the same original as
+/// Edit->getReg().
+bool InlineSpiller::isSnippet(const LiveInterval &SnipLI) {
+ unsigned Reg = Edit->getReg();
+
+ // A snippet is a tiny live range with only a single instruction using it
+ // besides copies to/from Reg or spills/fills. We accept:
+ //
+ // %snip = COPY %Reg / FILL fi#
+ // %snip = USE %snip
+ // %Reg = COPY %snip / SPILL %snip, fi#
+ //
+ if (SnipLI.getNumValNums() > 2 || !LIS.intervalIsInOneMBB(SnipLI))
+ return false;
+
+ MachineInstr *UseMI = 0;
+
+ // Check that all uses satisfy our criteria.
+ for (MachineRegisterInfo::reg_nodbg_iterator
+ RI = MRI.reg_nodbg_begin(SnipLI.reg);
+ MachineInstr *MI = RI.skipInstruction();) {
+
+ // Allow copies to/from Reg.
+ if (isFullCopyOf(MI, Reg))
+ continue;
- // Try splitting into single block intervals.
- SplitAnalysis::BlockPtrSet blocks;
- if (splitAnalysis_.getMultiUseBlocks(blocks)) {
- if (SplitEditor(splitAnalysis_, lis_, vrm_, *newIntervals_)
- .splitSingleBlocks(blocks))
- return true;
+ // Allow stack slot loads.
+ int FI;
+ if (SnipLI.reg == TII.isLoadFromStackSlot(MI, FI) && FI == StackSlot)
+ continue;
+
+ // Allow stack slot stores.
+ if (SnipLI.reg == TII.isStoreToStackSlot(MI, FI) && FI == StackSlot)
+ continue;
+
+ // Allow a single additional instruction.
+ if (UseMI && MI != UseMI)
+ return false;
+ UseMI = MI;
}
+ return true;
+}
+
+/// collectRegsToSpill - Collect live range snippets that only have a single
+/// real use.
+void InlineSpiller::collectRegsToSpill() {
+ unsigned Reg = Edit->getReg();
- // Try splitting inside a basic block.
- if (const MachineBasicBlock *MBB = splitAnalysis_.getBlockForInsideSplit()) {
- if (SplitEditor(splitAnalysis_, lis_, vrm_, *newIntervals_)
- .splitInsideBlock(MBB))
- return true;
+ // Main register always spills.
+ RegsToSpill.assign(1, Reg);
+ SnippetCopies.clear();
+
+ // Snippets all have the same original, so there can't be any for an original
+ // register.
+ if (Original == Reg)
+ return;
+
+ for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Reg);
+ MachineInstr *MI = RI.skipInstruction();) {
+ unsigned SnipReg = isFullCopyOf(MI, Reg);
+ if (!isSibling(SnipReg))
+ continue;
+ LiveInterval &SnipLI = LIS.getInterval(SnipReg);
+ if (!isSnippet(SnipLI))
+ continue;
+ SnippetCopies.insert(MI);
+ if (!isRegToSpill(SnipReg))
+ RegsToSpill.push_back(SnipReg);
+
+ DEBUG(dbgs() << "\talso spill snippet " << SnipLI << '\n');
}
+}
+
+
+//===----------------------------------------------------------------------===//
+// Sibling Values
+//===----------------------------------------------------------------------===//
+
+// After live range splitting, some values to be spilled may be defined by
+// copies from sibling registers. We trace the sibling copies back to the
+// original value if it still exists. We need it for rematerialization.
+//
+// Even when the value can't be rematerialized, we still want to determine if
+// the value has already been spilled, or we may want to hoist the spill from a
+// loop.
- // We may have been able to split out some uses, but the original interval is
- // intact, and it should still be spilled.
- return false;
+bool InlineSpiller::isSibling(unsigned Reg) {
+ return TargetRegisterInfo::isVirtualRegister(Reg) &&
+ VRM.getOriginal(Reg) == Original;
}
-/// allUsesAvailableAt - Return true if all registers used by OrigMI at
-/// OrigIdx are also available with the same value at UseIdx.
-bool InlineSpiller::allUsesAvailableAt(const MachineInstr *OrigMI,
- SlotIndex OrigIdx,
- SlotIndex UseIdx) {
- OrigIdx = OrigIdx.getUseIndex();
- 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() == li_->reg)
+/// traceSiblingValue - Trace a value that is about to be spilled back to the
+/// real defining instructions by looking through sibling copies. Always stay
+/// within the range of OrigVNI so the registers are known to carry the same
+/// value.
+///
+/// Determine if the value is defined by all reloads, so spilling isn't
+/// necessary - the value is already in the stack slot.
+///
+/// Return a defining instruction that may be a candidate for rematerialization.
+///
+MachineInstr *InlineSpiller::traceSiblingValue(unsigned UseReg, VNInfo *UseVNI,
+ VNInfo *OrigVNI) {
+ DEBUG(dbgs() << "Tracing value " << PrintReg(UseReg) << ':'
+ << UseVNI->id << '@' << UseVNI->def << '\n');
+ SmallPtrSet<VNInfo*, 8> Visited;
+ SmallVector<std::pair<unsigned, VNInfo*>, 8> WorkList;
+ WorkList.push_back(std::make_pair(UseReg, UseVNI));
+
+ // Best spill candidate seen so far. This must dominate UseVNI.
+ SibValueInfo SVI(UseReg, UseVNI);
+ MachineBasicBlock *UseMBB = LIS.getMBBFromIndex(UseVNI->def);
+ unsigned SpillDepth = Loops.getLoopDepth(UseMBB);
+ bool SeenOrigPHI = false; // Original PHI met.
+
+ do {
+ unsigned Reg;
+ VNInfo *VNI;
+ tie(Reg, VNI) = WorkList.pop_back_val();
+ if (!Visited.insert(VNI))
continue;
- // Reserved registers are OK.
- if (MO.isUndef() || !lis_.hasInterval(MO.getReg()))
+
+ // Is this value a better spill candidate?
+ if (!isRegToSpill(Reg)) {
+ MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
+ if (MBB != UseMBB && MDT.dominates(MBB, UseMBB)) {
+ // This is a valid spill location dominating UseVNI.
+ // Prefer to spill at a smaller loop depth.
+ unsigned Depth = Loops.getLoopDepth(MBB);
+ if (Depth < SpillDepth) {
+ DEBUG(dbgs() << " spill depth " << Depth << ": " << PrintReg(Reg)
+ << ':' << VNI->id << '@' << VNI->def << '\n');
+ SVI.SpillReg = Reg;
+ SVI.SpillVNI = VNI;
+ SpillDepth = Depth;
+ }
+ }
+ }
+
+ // Trace through PHI-defs created by live range splitting.
+ if (VNI->isPHIDef()) {
+ if (VNI->def == OrigVNI->def) {
+ DEBUG(dbgs() << " orig phi value " << PrintReg(Reg) << ':'
+ << VNI->id << '@' << VNI->def << '\n');
+ SeenOrigPHI = true;
+ continue;
+ }
+ // Get values live-out of predecessors.
+ LiveInterval &LI = LIS.getInterval(Reg);
+ MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
+ for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI) {
+ VNInfo *PVNI = LI.getVNInfoAt(LIS.getMBBEndIdx(*PI).getPrevSlot());
+ if (PVNI)
+ WorkList.push_back(std::make_pair(Reg, PVNI));
+ }
continue;
- // We don't want to move any defs.
- if (MO.isDef())
- return false;
- // We cannot depend on virtual registers in spillIs_. They will be spilled.
- for (unsigned si = 0, se = spillIs_->size(); si != se; ++si)
- if ((*spillIs_)[si]->reg == MO.getReg())
- return false;
+ }
+
+ MachineInstr *MI = LIS.getInstructionFromIndex(VNI->def);
+ assert(MI && "Missing def");
+
+ // Trace through sibling copies.
+ if (unsigned SrcReg = isFullCopyOf(MI, Reg)) {
+ if (isSibling(SrcReg)) {
+ LiveInterval &SrcLI = LIS.getInterval(SrcReg);
+ VNInfo *SrcVNI = SrcLI.getVNInfoAt(VNI->def.getUseIndex());
+ assert(SrcVNI && "Copy from non-existing value");
+ DEBUG(dbgs() << " copy of " << PrintReg(SrcReg) << ':'
+ << SrcVNI->id << '@' << SrcVNI->def << '\n');
+ WorkList.push_back(std::make_pair(SrcReg, SrcVNI));
+ continue;
+ }
+ }
- LiveInterval &LI = lis_.getInterval(MO.getReg());
- const VNInfo *OVNI = LI.getVNInfoAt(OrigIdx);
- if (!OVNI)
+ // Track reachable reloads.
+ int FI;
+ if (Reg == TII.isLoadFromStackSlot(MI, FI) && FI == StackSlot) {
+ DEBUG(dbgs() << " reload " << PrintReg(Reg) << ':'
+ << VNI->id << "@" << VNI->def << '\n');
+ SVI.AllDefsAreReloads = true;
continue;
- if (OVNI != LI.getVNInfoAt(UseIdx))
- return false;
+ }
+
+ // We have an 'original' def. Don't record trivial cases.
+ if (VNI == UseVNI) {
+ DEBUG(dbgs() << "Not a sibling copy.\n");
+ return MI;
+ }
+
+ // Potential remat candidate.
+ DEBUG(dbgs() << " def " << PrintReg(Reg) << ':'
+ << VNI->id << '@' << VNI->def << '\t' << *MI);
+ SVI.DefMI = MI;
+ } while (!WorkList.empty());
+
+ if (SeenOrigPHI || SVI.DefMI)
+ SVI.AllDefsAreReloads = false;
+
+ DEBUG({
+ if (SVI.AllDefsAreReloads)
+ dbgs() << "All defs are reloads.\n";
+ else
+ dbgs() << "Prefer to spill " << PrintReg(SVI.SpillReg) << ':'
+ << SVI.SpillVNI->id << '@' << SVI.SpillVNI->def << '\n';
+ });
+ SibValues.insert(std::make_pair(UseVNI, SVI));
+ return SVI.DefMI;
+}
+
+/// analyzeSiblingValues - Trace values defined by sibling copies back to
+/// something that isn't a sibling copy.
+///
+/// Keep track of values that may be rematerializable.
+void InlineSpiller::analyzeSiblingValues() {
+ SibValues.clear();
+
+ // No siblings at all?
+ if (Edit->getReg() == Original)
+ return;
+
+ LiveInterval &OrigLI = LIS.getInterval(Original);
+ for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i) {
+ unsigned Reg = RegsToSpill[i];
+ LiveInterval &LI = LIS.getInterval(Reg);
+ for (LiveInterval::const_vni_iterator VI = LI.vni_begin(),
+ VE = LI.vni_end(); VI != VE; ++VI) {
+ VNInfo *VNI = *VI;
+ if (VNI->isUnused())
+ continue;
+ MachineInstr *DefMI = 0;
+ // Check possible sibling copies.
+ if (VNI->isPHIDef() || VNI->getCopy()) {
+ VNInfo *OrigVNI = OrigLI.getVNInfoAt(VNI->def);
+ if (OrigVNI->def != VNI->def)
+ DefMI = traceSiblingValue(Reg, VNI, OrigVNI);
+ }
+ if (!DefMI && !VNI->isPHIDef())
+ DefMI = LIS.getInstructionFromIndex(VNI->def);
+ if (DefMI && Edit->checkRematerializable(VNI, DefMI, TII, AA)) {
+ DEBUG(dbgs() << "Value " << PrintReg(Reg) << ':' << VNI->id << '@'
+ << VNI->def << " may remat from " << *DefMI);
+ }
+ }
+ }
+}
+
+/// hoistSpill - Given a sibling copy that defines a value to be spilled, insert
+/// a spill at a better location.
+bool InlineSpiller::hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI) {
+ SlotIndex Idx = LIS.getInstructionIndex(CopyMI);
+ VNInfo *VNI = SpillLI.getVNInfoAt(Idx.getDefIndex());
+ assert(VNI && VNI->def == Idx.getDefIndex() && "Not defined by copy");
+ SibValueMap::const_iterator I = SibValues.find(VNI);
+ if (I == SibValues.end())
+ return false;
+
+ const SibValueInfo &SVI = I->second;
+
+ // Let the normal folding code deal with the boring case.
+ if (!SVI.AllDefsAreReloads && SVI.SpillVNI == VNI)
+ return false;
+
+ // Conservatively extend the stack slot range to the range of the original
+ // value. We may be able to do better with stack slot coloring by being more
+ // careful here.
+ assert(StackInt && "No stack slot assigned yet.");
+ LiveInterval &OrigLI = LIS.getInterval(Original);
+ VNInfo *OrigVNI = OrigLI.getVNInfoAt(Idx);
+ StackInt->MergeValueInAsValue(OrigLI, OrigVNI, StackInt->getValNumInfo(0));
+ DEBUG(dbgs() << "\tmerged orig valno " << OrigVNI->id << ": "
+ << *StackInt << '\n');
+
+ // Already spilled everywhere.
+ if (SVI.AllDefsAreReloads)
+ return true;
+
+ // We are going to spill SVI.SpillVNI immediately after its def, so clear out
+ // any later spills of the same value.
+ eliminateRedundantSpills(LIS.getInterval(SVI.SpillReg), SVI.SpillVNI);
+
+ MachineBasicBlock *MBB = LIS.getMBBFromIndex(SVI.SpillVNI->def);
+ MachineBasicBlock::iterator MII;
+ if (SVI.SpillVNI->isPHIDef())
+ MII = MBB->SkipPHIsAndLabels(MBB->begin());
+ else {
+ MII = LIS.getInstructionFromIndex(SVI.SpillVNI->def);
+ ++MII;
}
+ // Insert spill without kill flag immediately after def.
+ TII.storeRegToStackSlot(*MBB, MII, SVI.SpillReg, false, StackSlot,
+ MRI.getRegClass(SVI.SpillReg), &TRI);
+ --MII; // Point to store instruction.
+ LIS.InsertMachineInstrInMaps(MII);
+ VRM.addSpillSlotUse(StackSlot, MII);
+ DEBUG(dbgs() << "\thoisted: " << SVI.SpillVNI->def << '\t' << *MII);
return true;
}
-/// reMaterializeFor - Attempt to rematerialize li_->reg before MI instead of
-/// reloading it.
-bool InlineSpiller::reMaterializeFor(MachineBasicBlock::iterator MI) {
- SlotIndex UseIdx = lis_.getInstructionIndex(MI).getUseIndex();
- VNInfo *OrigVNI = li_->getVNInfoAt(UseIdx);
- if (!OrigVNI) {
+/// eliminateRedundantSpills - SLI:VNI is known to be on the stack. Remove any
+/// redundant spills of this value in SLI.reg and sibling copies.
+void InlineSpiller::eliminateRedundantSpills(LiveInterval &SLI, VNInfo *VNI) {
+ assert(VNI && "Missing value");
+ SmallVector<std::pair<LiveInterval*, VNInfo*>, 8> WorkList;
+ WorkList.push_back(std::make_pair(&SLI, VNI));
+ assert(StackInt && "No stack slot assigned yet.");
+
+ do {
+ LiveInterval *LI;
+ tie(LI, VNI) = WorkList.pop_back_val();
+ unsigned Reg = LI->reg;
+ DEBUG(dbgs() << "Checking redundant spills for " << PrintReg(Reg) << ':'
+ << VNI->id << '@' << VNI->def << '\n');
+
+ // Regs to spill are taken care of.
+ if (isRegToSpill(Reg))
+ continue;
+
+ // Add all of VNI's live range to StackInt.
+ StackInt->MergeValueInAsValue(*LI, VNI, StackInt->getValNumInfo(0));
+ DEBUG(dbgs() << "Merged to stack int: " << *StackInt << '\n');
+
+ // Find all spills and copies of VNI.
+ for (MachineRegisterInfo::use_nodbg_iterator UI = MRI.use_nodbg_begin(Reg);
+ MachineInstr *MI = UI.skipInstruction();) {
+ if (!MI->isCopy() && !MI->getDesc().mayStore())
+ continue;
+ SlotIndex Idx = LIS.getInstructionIndex(MI);
+ if (LI->getVNInfoAt(Idx) != VNI)
+ continue;
+
+ // Follow sibling copies down the dominator tree.
+ if (unsigned DstReg = isFullCopyOf(MI, Reg)) {
+ if (isSibling(DstReg)) {
+ LiveInterval &DstLI = LIS.getInterval(DstReg);
+ VNInfo *DstVNI = DstLI.getVNInfoAt(Idx.getDefIndex());
+ assert(DstVNI && "Missing defined value");
+ assert(DstVNI->def == Idx.getDefIndex() && "Wrong copy def slot");
+ WorkList.push_back(std::make_pair(&DstLI, DstVNI));
+ }
+ continue;
+ }
+
+ // Erase spills.
+ int FI;
+ if (Reg == TII.isStoreToStackSlot(MI, FI) && FI == StackSlot) {
+ DEBUG(dbgs() << "Redundant spill " << Idx << '\t' << *MI);
+ // eliminateDeadDefs won't normally remove stores, so switch opcode.
+ MI->setDesc(TII.get(TargetOpcode::KILL));
+ DeadDefs.push_back(MI);
+ }
+ }
+ } while (!WorkList.empty());
+}
+
+
+//===----------------------------------------------------------------------===//
+// Rematerialization
+//===----------------------------------------------------------------------===//
+
+/// markValueUsed - Remember that VNI failed to rematerialize, so its defining
+/// instruction cannot be eliminated. See through snippet copies
+void InlineSpiller::markValueUsed(LiveInterval *LI, VNInfo *VNI) {
+ SmallVector<std::pair<LiveInterval*, VNInfo*>, 8> WorkList;
+ WorkList.push_back(std::make_pair(LI, VNI));
+ do {
+ tie(LI, VNI) = WorkList.pop_back_val();
+ if (!UsedValues.insert(VNI))
+ continue;
+
+ if (VNI->isPHIDef()) {
+ MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
+ for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI) {
+ VNInfo *PVNI = LI->getVNInfoAt(LIS.getMBBEndIdx(*PI).getPrevSlot());
+ if (PVNI)
+ WorkList.push_back(std::make_pair(LI, PVNI));
+ }
+ continue;
+ }
+
+ // Follow snippet copies.
+ MachineInstr *MI = LIS.getInstructionFromIndex(VNI->def);
+ if (!SnippetCopies.count(MI))
+ continue;
+ LiveInterval &SnipLI = LIS.getInterval(MI->getOperand(1).getReg());
+ assert(isRegToSpill(SnipLI.reg) && "Unexpected register in copy");
+ VNInfo *SnipVNI = SnipLI.getVNInfoAt(VNI->def.getUseIndex());
+ assert(SnipVNI && "Snippet undefined before copy");
+ WorkList.push_back(std::make_pair(&SnipLI, SnipVNI));
+ } while (!WorkList.empty());
+}
+
+/// reMaterializeFor - Attempt to rematerialize before MI instead of reloading.
+bool InlineSpiller::reMaterializeFor(LiveInterval &VirtReg,
+ MachineBasicBlock::iterator MI) {
+ SlotIndex UseIdx = LIS.getInstructionIndex(MI).getUseIndex();
+ VNInfo *ParentVNI = VirtReg.getVNInfoAt(UseIdx);
+
+ if (!ParentVNI) {
DEBUG(dbgs() << "\tadding <undef> flags: ");
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
- if (MO.isReg() && MO.isUse() && MO.getReg() == li_->reg)
+ if (MO.isReg() && MO.isUse() && MO.getReg() == VirtReg.reg)
MO.setIsUndef();
}
DEBUG(dbgs() << UseIdx << '\t' << *MI);
return true;
}
- if (!reMattable_.count(OrigVNI)) {
- DEBUG(dbgs() << "\tusing non-remat valno " << OrigVNI->id << ": "
- << UseIdx << '\t' << *MI);
+
+ if (SnippetCopies.count(MI))
return false;
- }
- MachineInstr *OrigMI = lis_.getInstructionFromIndex(OrigVNI->def);
- if (!allUsesAvailableAt(OrigMI, OrigVNI->def, UseIdx)) {
- usedValues_.insert(OrigVNI);
+
+ // Use an OrigVNI from traceSiblingValue when ParentVNI is a sibling copy.
+ LiveRangeEdit::Remat RM(ParentVNI);
+ SibValueMap::const_iterator SibI = SibValues.find(ParentVNI);
+ if (SibI != SibValues.end())
+ RM.OrigMI = SibI->second.DefMI;
+ if (!Edit->canRematerializeAt(RM, UseIdx, false, LIS)) {
+ markValueUsed(&VirtReg, ParentVNI);
DEBUG(dbgs() << "\tcannot remat for " << UseIdx << '\t' << *MI);
return false;
}
- // If the instruction also writes li_->reg, it had better not require the same
- // register for uses and defs.
+ // If the instruction also writes VirtReg.reg, it had better not require the
+ // same register for uses and defs.
bool Reads, Writes;
SmallVector<unsigned, 8> Ops;
- tie(Reads, Writes) = MI->readsWritesVirtualRegister(li_->reg, &Ops);
+ tie(Reads, Writes) = MI->readsWritesVirtualRegister(VirtReg.reg, &Ops);
if (Writes) {
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(Ops[i]);
if (MO.isUse() ? MI->isRegTiedToDefOperand(Ops[i]) : MO.getSubReg()) {
- usedValues_.insert(OrigVNI);
+ markValueUsed(&VirtReg, ParentVNI);
DEBUG(dbgs() << "\tcannot remat tied reg: " << UseIdx << '\t' << *MI);
return false;
}
}
}
+ // Before rematerializing into a register for a single instruction, try to
+ // fold a load into the instruction. That avoids allocating a new register.
+ if (RM.OrigMI->getDesc().canFoldAsLoad() &&
+ foldMemoryOperand(MI, Ops, RM.OrigMI)) {
+ Edit->markRematerialized(RM.ParentVNI);
+ return true;
+ }
+
// Alocate a new register for the remat.
- unsigned NewVReg = mri_.createVirtualRegister(rc_);
- vrm_.grow();
- LiveInterval &NewLI = lis_.getOrCreateInterval(NewVReg);
+ LiveInterval &NewLI = Edit->createFrom(Original, LIS, VRM);
NewLI.markNotSpillable();
- newIntervals_->push_back(&NewLI);
// Finally we can rematerialize OrigMI before MI.
- MachineBasicBlock &MBB = *MI->getParent();
- tii_.reMaterialize(MBB, MI, NewLI.reg, 0, OrigMI, tri_);
- MachineBasicBlock::iterator RematMI = MI;
- SlotIndex DefIdx = lis_.InsertMachineInstrInMaps(--RematMI).getDefIndex();
- DEBUG(dbgs() << "\tremat: " << DefIdx << '\t' << *RematMI);
+ SlotIndex DefIdx = Edit->rematerializeAt(*MI->getParent(), MI, NewLI.reg, RM,
+ LIS, TII, TRI);
+ DEBUG(dbgs() << "\tremat: " << DefIdx << '\t'
+ << *LIS.getInstructionFromIndex(DefIdx));
// Replace operands
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(Ops[i]);
- if (MO.isReg() && MO.isUse() && MO.getReg() == li_->reg) {
- MO.setReg(NewVReg);
+ if (MO.isReg() && MO.isUse() && MO.getReg() == VirtReg.reg) {
+ MO.setReg(NewLI.reg);
MO.setIsKill();
}
}
DEBUG(dbgs() << "\t " << UseIdx << '\t' << *MI);
- VNInfo *DefVNI = NewLI.getNextValue(DefIdx, 0, true,
- lis_.getVNInfoAllocator());
+ VNInfo *DefVNI = NewLI.getNextValue(DefIdx, 0, LIS.getVNInfoAllocator());
NewLI.addRange(LiveRange(DefIdx, UseIdx.getDefIndex(), DefVNI));
DEBUG(dbgs() << "\tinterval: " << NewLI << '\n');
return true;
}
-/// reMaterializeAll - Try to rematerialize as many uses of li_ as possible,
+/// reMaterializeAll - Try to rematerialize as many uses as possible,
/// and trim the live ranges after.
void InlineSpiller::reMaterializeAll() {
- // Do a quick scan of the interval values to find if any are remattable.
- reMattable_.clear();
- usedValues_.clear();
- for (LiveInterval::const_vni_iterator I = li_->vni_begin(),
- E = li_->vni_end(); I != E; ++I) {
- VNInfo *VNI = *I;
- if (VNI->isUnused() || !VNI->isDefAccurate())
- continue;
- MachineInstr *DefMI = lis_.getInstructionFromIndex(VNI->def);
- if (!DefMI || !tii_.isTriviallyReMaterializable(DefMI))
- continue;
- reMattable_.insert(VNI);
- }
-
- // Often, no defs are remattable.
- if (reMattable_.empty())
+ // analyzeSiblingValues has already tested all relevant defining instructions.
+ if (!Edit->anyRematerializable(LIS, TII, AA))
return;
- // Try to remat before all uses of li_->reg.
- bool anyRemat = false;
- for (MachineRegisterInfo::use_nodbg_iterator
- RI = mri_.use_nodbg_begin(li_->reg);
- MachineInstr *MI = RI.skipInstruction();)
- anyRemat |= reMaterializeFor(MI);
+ UsedValues.clear();
+ // Try to remat before all uses of snippets.
+ bool anyRemat = false;
+ for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i) {
+ unsigned Reg = RegsToSpill[i];
+ LiveInterval &LI = LIS.getInterval(Reg);
+ for (MachineRegisterInfo::use_nodbg_iterator
+ RI = MRI.use_nodbg_begin(Reg);
+ MachineInstr *MI = RI.skipInstruction();)
+ anyRemat |= reMaterializeFor(LI, MI);
+ }
if (!anyRemat)
return;
// Remove any values that were completely rematted.
- bool anyRemoved = false;
- for (SmallPtrSet<VNInfo*, 8>::iterator I = reMattable_.begin(),
- E = reMattable_.end(); I != E; ++I) {
- VNInfo *VNI = *I;
- if (VNI->hasPHIKill() || usedValues_.count(VNI))
- continue;
- MachineInstr *DefMI = lis_.getInstructionFromIndex(VNI->def);
- DEBUG(dbgs() << "\tremoving dead def: " << VNI->def << '\t' << *DefMI);
- lis_.RemoveMachineInstrFromMaps(DefMI);
- vrm_.RemoveMachineInstrFromMaps(DefMI);
- DefMI->eraseFromParent();
- VNI->setIsDefAccurate(false);
- anyRemoved = true;
+ for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i) {
+ unsigned Reg = RegsToSpill[i];
+ LiveInterval &LI = LIS.getInterval(Reg);
+ for (LiveInterval::vni_iterator I = LI.vni_begin(), E = LI.vni_end();
+ I != E; ++I) {
+ VNInfo *VNI = *I;
+ if (VNI->isUnused() || VNI->isPHIDef() || UsedValues.count(VNI))
+ continue;
+ MachineInstr *MI = LIS.getInstructionFromIndex(VNI->def);
+ MI->addRegisterDead(Reg, &TRI);
+ if (!MI->allDefsAreDead())
+ continue;
+ DEBUG(dbgs() << "All defs dead: " << *MI);
+ DeadDefs.push_back(MI);
+ }
}
- if (!anyRemoved)
+ // Eliminate dead code after remat. Note that some snippet copies may be
+ // deleted here.
+ if (DeadDefs.empty())
return;
-
- // Removing values may cause debug uses where li_ is not live.
- for (MachineRegisterInfo::use_iterator RI = mri_.use_begin(li_->reg);
- MachineInstr *MI = RI.skipInstruction();) {
- if (!MI->isDebugValue())
+ DEBUG(dbgs() << "Remat created " << DeadDefs.size() << " dead defs.\n");
+ Edit->eliminateDeadDefs(DeadDefs, LIS, VRM, TII);
+
+ // Get rid of deleted and empty intervals.
+ for (unsigned i = RegsToSpill.size(); i != 0; --i) {
+ unsigned Reg = RegsToSpill[i-1];
+ if (!LIS.hasInterval(Reg)) {
+ RegsToSpill.erase(RegsToSpill.begin() + (i - 1));
continue;
- // Try to preserve the debug value if li_ is live immediately after it.
- MachineBasicBlock::iterator NextMI = MI;
- ++NextMI;
- if (NextMI != MI->getParent()->end() && !lis_.isNotInMIMap(NextMI)) {
- VNInfo *VNI = li_->getVNInfoAt(lis_.getInstructionIndex(NextMI));
- if (VNI && (VNI->hasPHIKill() || usedValues_.count(VNI)))
- continue;
}
- DEBUG(dbgs() << "Removing debug info due to remat:" << "\t" << *MI);
- MI->eraseFromParent();
+ LiveInterval &LI = LIS.getInterval(Reg);
+ if (!LI.empty())
+ continue;
+ Edit->eraseVirtReg(Reg, LIS);
+ RegsToSpill.erase(RegsToSpill.begin() + (i - 1));
}
+ DEBUG(dbgs() << RegsToSpill.size() << " registers to spill after remat.\n");
}
-/// If MI is a load or store of stackSlot_, it can be removed.
-bool InlineSpiller::coalesceStackAccess(MachineInstr *MI) {
+
+//===----------------------------------------------------------------------===//
+// Spilling
+//===----------------------------------------------------------------------===//
+
+/// If MI is a load or store of StackSlot, it can be removed.
+bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, unsigned Reg) {
int FI = 0;
- unsigned reg;
- if (!(reg = tii_.isLoadFromStackSlot(MI, FI)) &&
- !(reg = tii_.isStoreToStackSlot(MI, FI)))
+ unsigned InstrReg;
+ if (!(InstrReg = TII.isLoadFromStackSlot(MI, FI)) &&
+ !(InstrReg = TII.isStoreToStackSlot(MI, FI)))
return false;
// We have a stack access. Is it the right register and slot?
- if (reg != li_->reg || FI != stackSlot_)
+ if (InstrReg != Reg || FI != StackSlot)
return false;
DEBUG(dbgs() << "Coalescing stack access: " << *MI);
- lis_.RemoveMachineInstrFromMaps(MI);
+ LIS.RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
return true;
}
/// foldMemoryOperand - Try folding stack slot references in Ops into MI.
-/// Return true on success, and MI will be erased.
+/// @param MI Instruction using or defining the current register.
+/// @param Ops Operand indices from readsWritesVirtualRegister().
+/// @param LoadMI Load instruction to use instead of stack slot when non-null.
+/// @return True on success, and MI will be erased.
bool InlineSpiller::foldMemoryOperand(MachineBasicBlock::iterator MI,
- const SmallVectorImpl<unsigned> &Ops) {
+ const SmallVectorImpl<unsigned> &Ops,
+ MachineInstr *LoadMI) {
// TargetInstrInfo::foldMemoryOperand only expects explicit, non-tied
// operands.
SmallVector<unsigned, 8> FoldOps;
// FIXME: Teach targets to deal with subregs.
if (MO.getSubReg())
return false;
+ // We cannot fold a load instruction into a def.
+ if (LoadMI && MO.isDef())
+ return false;
// Tied use operands should not be passed to foldMemoryOperand.
if (!MI->isRegTiedToDefOperand(Idx))
FoldOps.push_back(Idx);
}
- MachineInstr *FoldMI = tii_.foldMemoryOperand(MI, FoldOps, stackSlot_);
+ MachineInstr *FoldMI =
+ LoadMI ? TII.foldMemoryOperand(MI, FoldOps, LoadMI)
+ : TII.foldMemoryOperand(MI, FoldOps, StackSlot);
if (!FoldMI)
return false;
- lis_.ReplaceMachineInstrInMaps(MI, FoldMI);
- vrm_.addSpillSlotUse(stackSlot_, FoldMI);
+ LIS.ReplaceMachineInstrInMaps(MI, FoldMI);
+ if (!LoadMI)
+ VRM.addSpillSlotUse(StackSlot, FoldMI);
MI->eraseFromParent();
DEBUG(dbgs() << "\tfolded: " << *FoldMI);
return true;
/// insertReload - Insert a reload of NewLI.reg before MI.
void InlineSpiller::insertReload(LiveInterval &NewLI,
+ SlotIndex Idx,
MachineBasicBlock::iterator MI) {
MachineBasicBlock &MBB = *MI->getParent();
- SlotIndex Idx = lis_.getInstructionIndex(MI).getDefIndex();
- tii_.loadRegFromStackSlot(MBB, MI, NewLI.reg, stackSlot_, rc_, &tri_);
+ TII.loadRegFromStackSlot(MBB, MI, NewLI.reg, StackSlot,
+ MRI.getRegClass(NewLI.reg), &TRI);
--MI; // Point to load instruction.
- SlotIndex LoadIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();
- vrm_.addSpillSlotUse(stackSlot_, MI);
+ SlotIndex LoadIdx = LIS.InsertMachineInstrInMaps(MI).getDefIndex();
+ VRM.addSpillSlotUse(StackSlot, MI);
DEBUG(dbgs() << "\treload: " << LoadIdx << '\t' << *MI);
- VNInfo *LoadVNI = NewLI.getNextValue(LoadIdx, 0, true,
- lis_.getVNInfoAllocator());
+ VNInfo *LoadVNI = NewLI.getNextValue(LoadIdx, 0,
+ LIS.getVNInfoAllocator());
NewLI.addRange(LiveRange(LoadIdx, Idx, LoadVNI));
}
/// insertSpill - Insert a spill of NewLI.reg after MI.
-void InlineSpiller::insertSpill(LiveInterval &NewLI,
- MachineBasicBlock::iterator MI) {
+void InlineSpiller::insertSpill(LiveInterval &NewLI, const LiveInterval &OldLI,
+ SlotIndex Idx, MachineBasicBlock::iterator MI) {
MachineBasicBlock &MBB = *MI->getParent();
- SlotIndex Idx = lis_.getInstructionIndex(MI).getDefIndex();
- tii_.storeRegToStackSlot(MBB, ++MI, NewLI.reg, true, stackSlot_, rc_, &tri_);
+ TII.storeRegToStackSlot(MBB, ++MI, NewLI.reg, true, StackSlot,
+ MRI.getRegClass(NewLI.reg), &TRI);
--MI; // Point to store instruction.
- SlotIndex StoreIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();
- vrm_.addSpillSlotUse(stackSlot_, MI);
+ SlotIndex StoreIdx = LIS.InsertMachineInstrInMaps(MI).getDefIndex();
+ VRM.addSpillSlotUse(StackSlot, MI);
DEBUG(dbgs() << "\tspilled: " << StoreIdx << '\t' << *MI);
- VNInfo *StoreVNI = NewLI.getNextValue(Idx, 0, true,
- lis_.getVNInfoAllocator());
+ VNInfo *StoreVNI = NewLI.getNextValue(Idx, 0, LIS.getVNInfoAllocator());
NewLI.addRange(LiveRange(Idx, StoreIdx, StoreVNI));
}
-void InlineSpiller::spill(LiveInterval *li,
- SmallVectorImpl<LiveInterval*> &newIntervals,
- SmallVectorImpl<LiveInterval*> &spillIs) {
- DEBUG(dbgs() << "Inline spilling " << *li << "\n");
- assert(li->isSpillable() && "Attempting to spill already spilled value.");
- assert(!li->isStackSlot() && "Trying to spill a stack slot.");
-
- li_ = li;
- newIntervals_ = &newIntervals;
- rc_ = mri_.getRegClass(li->reg);
- spillIs_ = &spillIs;
-
- if (split())
- return;
-
- reMaterializeAll();
-
- // Remat may handle everything.
- if (li_->empty())
- return;
+/// spillAroundUses - insert spill code around each use of Reg.
+void InlineSpiller::spillAroundUses(unsigned Reg) {
+ LiveInterval &OldLI = LIS.getInterval(Reg);
- stackSlot_ = vrm_.getStackSlot(li->reg);
- if (stackSlot_ == VirtRegMap::NO_STACK_SLOT)
- stackSlot_ = vrm_.assignVirt2StackSlot(li->reg);
-
- // Iterate over instructions using register.
- for (MachineRegisterInfo::reg_iterator RI = mri_.reg_begin(li->reg);
+ // Iterate over instructions using Reg.
+ for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Reg);
MachineInstr *MI = RI.skipInstruction();) {
// Debug values are not allowed to affect codegen.
uint64_t Offset = MI->getOperand(1).getImm();
const MDNode *MDPtr = MI->getOperand(2).getMetadata();
DebugLoc DL = MI->getDebugLoc();
- if (MachineInstr *NewDV = tii_.emitFrameIndexDebugValue(mf_, stackSlot_,
+ if (MachineInstr *NewDV = TII.emitFrameIndexDebugValue(MF, StackSlot,
Offset, MDPtr, DL)) {
DEBUG(dbgs() << "Modifying debug info due to spill:" << "\t" << *MI);
MachineBasicBlock *MBB = MI->getParent();
continue;
}
+ // Ignore copies to/from snippets. We'll delete them.
+ if (SnippetCopies.count(MI))
+ continue;
+
// Stack slot accesses may coalesce away.
- if (coalesceStackAccess(MI))
+ if (coalesceStackAccess(MI, Reg))
continue;
// Analyze instruction.
bool Reads, Writes;
SmallVector<unsigned, 8> Ops;
- tie(Reads, Writes) = MI->readsWritesVirtualRegister(li->reg, &Ops);
+ tie(Reads, Writes) = MI->readsWritesVirtualRegister(Reg, &Ops);
+
+ // Find the slot index where this instruction reads and writes OldLI.
+ // This is usually the def slot, except for tied early clobbers.
+ SlotIndex Idx = LIS.getInstructionIndex(MI).getDefIndex();
+ if (VNInfo *VNI = OldLI.getVNInfoAt(Idx.getUseIndex()))
+ if (SlotIndex::isSameInstr(Idx, VNI->def))
+ Idx = VNI->def;
+
+ // Check for a sibling copy.
+ unsigned SibReg = isFullCopyOf(MI, Reg);
+ if (SibReg && isSibling(SibReg)) {
+ if (Writes) {
+ // Hoist the spill of a sib-reg copy.
+ if (hoistSpill(OldLI, MI)) {
+ // This COPY is now dead, the value is already in the stack slot.
+ MI->getOperand(0).setIsDead();
+ DeadDefs.push_back(MI);
+ continue;
+ }
+ } else {
+ // This is a reload for a sib-reg copy. Drop spills downstream.
+ LiveInterval &SibLI = LIS.getInterval(SibReg);
+ eliminateRedundantSpills(SibLI, SibLI.getVNInfoAt(Idx));
+ // The COPY will fold to a reload below.
+ }
+ }
// Attempt to fold memory ops.
if (foldMemoryOperand(MI, Ops))
// Allocate interval around instruction.
// FIXME: Infer regclass from instruction alone.
- unsigned NewVReg = mri_.createVirtualRegister(rc_);
- vrm_.grow();
- LiveInterval &NewLI = lis_.getOrCreateInterval(NewVReg);
+ LiveInterval &NewLI = Edit->createFrom(Reg, LIS, VRM);
NewLI.markNotSpillable();
if (Reads)
- insertReload(NewLI, MI);
+ insertReload(NewLI, Idx, MI);
// Rewrite instruction operands.
bool hasLiveDef = false;
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(Ops[i]);
- MO.setReg(NewVReg);
+ MO.setReg(NewLI.reg);
if (MO.isUse()) {
if (!MI->isRegTiedToDefOperand(Ops[i]))
MO.setIsKill();
hasLiveDef = true;
}
}
+ DEBUG(dbgs() << "\trewrite: " << Idx << '\t' << *MI);
// FIXME: Use a second vreg if instruction has no tied ops.
if (Writes && hasLiveDef)
- insertSpill(NewLI, MI);
+ insertSpill(NewLI, OldLI, Idx, MI);
DEBUG(dbgs() << "\tinterval: " << NewLI << '\n');
- newIntervals.push_back(&NewLI);
}
}
+
+/// spillAll - Spill all registers remaining after rematerialization.
+void InlineSpiller::spillAll() {
+ // Update LiveStacks now that we are committed to spilling.
+ if (StackSlot == VirtRegMap::NO_STACK_SLOT) {
+ StackSlot = VRM.assignVirt2StackSlot(Original);
+ StackInt = &LSS.getOrCreateInterval(StackSlot, MRI.getRegClass(Original));
+ StackInt->getNextValue(SlotIndex(), 0, LSS.getVNInfoAllocator());
+ } else
+ StackInt = &LSS.getInterval(StackSlot);
+
+ if (Original != Edit->getReg())
+ VRM.assignVirt2StackSlot(Edit->getReg(), StackSlot);
+
+ assert(StackInt->getNumValNums() == 1 && "Bad stack interval values");
+ for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i)
+ StackInt->MergeRangesInAsValue(LIS.getInterval(RegsToSpill[i]),
+ StackInt->getValNumInfo(0));
+ DEBUG(dbgs() << "Merged spilled regs: " << *StackInt << '\n');
+
+ // Spill around uses of all RegsToSpill.
+ for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i)
+ spillAroundUses(RegsToSpill[i]);
+
+ // Hoisted spills may cause dead code.
+ if (!DeadDefs.empty()) {
+ DEBUG(dbgs() << "Eliminating " << DeadDefs.size() << " dead defs\n");
+ Edit->eliminateDeadDefs(DeadDefs, LIS, VRM, TII);
+ }
+
+ // Finally delete the SnippetCopies.
+ for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Edit->getReg());
+ MachineInstr *MI = RI.skipInstruction();) {
+ assert(SnippetCopies.count(MI) && "Remaining use wasn't a snippet copy");
+ // FIXME: Do this with a LiveRangeEdit callback.
+ VRM.RemoveMachineInstrFromMaps(MI);
+ LIS.RemoveMachineInstrFromMaps(MI);
+ MI->eraseFromParent();
+ }
+
+ // Delete all spilled registers.
+ for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i)
+ Edit->eraseVirtReg(RegsToSpill[i], LIS);
+}
+
+void InlineSpiller::spill(LiveRangeEdit &edit) {
+ Edit = &edit;
+ assert(!TargetRegisterInfo::isStackSlot(edit.getReg())
+ && "Trying to spill a stack slot.");
+ // Share a stack slot among all descendants of Original.
+ Original = VRM.getOriginal(edit.getReg());
+ StackSlot = VRM.getStackSlot(Original);
+ StackInt = 0;
+
+ DEBUG(dbgs() << "Inline spilling "
+ << MRI.getRegClass(edit.getReg())->getName()
+ << ':' << edit.getParent() << "\nFrom original "
+ << LIS.getInterval(Original) << '\n');
+ assert(edit.getParent().isSpillable() &&
+ "Attempting to spill already spilled value.");
+ assert(DeadDefs.empty() && "Previous spill didn't remove dead defs");
+
+ collectRegsToSpill();
+ analyzeSiblingValues();
+ reMaterializeAll();
+
+ // Remat may handle everything.
+ if (!RegsToSpill.empty())
+ spillAll();
+
+ Edit->calculateRegClassAndHint(MF, LIS, Loops);
+}
projects / oota-llvm.git / blobdiff