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-rw-r--r--lib/CodeGen/InlineSpiller.cpp245
1 files changed, 113 insertions, 132 deletions
diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index b965bfd..7e4fbad 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -12,28 +12,43 @@
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "spiller"
+#define DEBUG_TYPE "regalloc"
#include "Spiller.h"
+#include "LiveRangeEdit.h"
#include "SplitKit.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"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
+static cl::opt<bool>
+VerifySpills("verify-spills", cl::desc("Verify after each spill/split"));
+
+static cl::opt<bool>
+ExtraSpillerSplits("extra-spiller-splits",
+ cl::desc("Enable additional splitting during splitting"));
+
namespace {
class InlineSpiller : public Spiller {
MachineFunctionPass &pass_;
MachineFunction &mf_;
LiveIntervals &lis_;
+ LiveStacks &lss_;
+ MachineDominatorTree &mdt_;
MachineLoopInfo &loops_;
+ AliasAnalysis *aa_;
VirtRegMap &vrm_;
MachineFrameInfo &mfi_;
MachineRegisterInfo &mri_;
@@ -44,16 +59,11 @@ class InlineSpiller : public Spiller {
SplitAnalysis splitAnalysis_;
// Variables that are valid during spill(), but used by multiple methods.
- LiveInterval *li_;
- SmallVectorImpl<LiveInterval*> *newIntervals_;
+ LiveRangeEdit *edit_;
const TargetRegisterClass *rc_;
int stackSlot_;
- const SmallVectorImpl<LiveInterval*> *spillIs_;
-
- // Values of the current interval that can potentially remat.
- SmallPtrSet<VNInfo*, 8> reMattable_;
- // Values in reMattable_ that failed to remat at some point.
+ // Values that failed to remat at some point.
SmallPtrSet<VNInfo*, 8> usedValues_;
~InlineSpiller() {}
@@ -65,7 +75,10 @@ public:
: pass_(pass),
mf_(mf),
lis_(pass.getAnalysis<LiveIntervals>()),
+ lss_(pass.getAnalysis<LiveStacks>()),
+ mdt_(pass.getAnalysis<MachineDominatorTree>()),
loops_(pass.getAnalysis<MachineLoopInfo>()),
+ aa_(&pass.getAnalysis<AliasAnalysis>()),
vrm_(vrm),
mfi_(*mf.getFrameInfo()),
mri_(mf.getRegInfo()),
@@ -76,13 +89,13 @@ public:
void spill(LiveInterval *li,
SmallVectorImpl<LiveInterval*> &newIntervals,
- SmallVectorImpl<LiveInterval*> &spillIs);
+ const SmallVectorImpl<LiveInterval*> &spillIs);
+
+ void spill(LiveRangeEdit &);
private:
bool split();
- bool allUsesAvailableAt(const MachineInstr *OrigMI, SlotIndex OrigIdx,
- SlotIndex UseIdx);
bool reMaterializeFor(MachineBasicBlock::iterator MI);
void reMaterializeAll();
@@ -98,6 +111,8 @@ namespace llvm {
Spiller *createInlineSpiller(MachineFunctionPass &pass,
MachineFunction &mf,
VirtRegMap &vrm) {
+ if (VerifySpills)
+ mf.verify(&pass);
return new InlineSpiller(pass, mf, vrm);
}
}
@@ -105,99 +120,68 @@ Spiller *createInlineSpiller(MachineFunctionPass &pass,
/// split - try splitting the current interval into pieces that may allocate
/// separately. Return true if successful.
bool InlineSpiller::split() {
- splitAnalysis_.analyze(li_);
-
- 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))
+ splitAnalysis_.analyze(&edit_->getParent());
+
+ // Try splitting around loops.
+ if (ExtraSpillerSplits) {
+ const MachineLoop *loop = splitAnalysis_.getBestSplitLoop();
+ if (loop) {
+ SplitEditor(splitAnalysis_, lis_, vrm_, mdt_, *edit_)
+ .splitAroundLoop(loop);
return true;
+ }
}
// Try splitting into single block intervals.
SplitAnalysis::BlockPtrSet blocks;
if (splitAnalysis_.getMultiUseBlocks(blocks)) {
- if (SplitEditor(splitAnalysis_, lis_, vrm_, *newIntervals_)
- .splitSingleBlocks(blocks))
- return true;
+ SplitEditor(splitAnalysis_, lis_, vrm_, mdt_, *edit_)
+ .splitSingleBlocks(blocks);
+ return true;
}
// Try splitting inside a basic block.
- if (const MachineBasicBlock *MBB = splitAnalysis_.getBlockForInsideSplit()) {
- if (SplitEditor(splitAnalysis_, lis_, vrm_, *newIntervals_)
- .splitInsideBlock(MBB))
+ if (ExtraSpillerSplits) {
+ const MachineBasicBlock *MBB = splitAnalysis_.getBlockForInsideSplit();
+ if (MBB){
+ SplitEditor(splitAnalysis_, lis_, vrm_, mdt_, *edit_)
+ .splitInsideBlock(MBB);
return true;
+ }
}
- // We may have been able to split out some uses, but the original interval is
- // intact, and it should still be spilled.
return false;
}
-/// 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)
- 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 spillIs_. They will be spilled.
- for (unsigned si = 0, se = spillIs_->size(); si != se; ++si)
- if ((*spillIs_)[si]->reg == MO.getReg())
- return false;
-
- LiveInterval &LI = lis_.getInterval(MO.getReg());
- const VNInfo *OVNI = LI.getVNInfoAt(OrigIdx);
- if (!OVNI)
- continue;
- if (OVNI != LI.getVNInfoAt(UseIdx))
- return false;
- }
- return true;
-}
-
-/// reMaterializeFor - Attempt to rematerialize li_->reg before MI instead of
+/// reMaterializeFor - Attempt to rematerialize edit_->getReg() before MI instead of
/// reloading it.
bool InlineSpiller::reMaterializeFor(MachineBasicBlock::iterator MI) {
SlotIndex UseIdx = lis_.getInstructionIndex(MI).getUseIndex();
- VNInfo *OrigVNI = li_->getVNInfoAt(UseIdx);
+ VNInfo *OrigVNI = edit_->getParent().getVNInfoAt(UseIdx);
+
if (!OrigVNI) {
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() == edit_->getReg())
MO.setIsUndef();
}
DEBUG(dbgs() << UseIdx << '\t' << *MI);
return true;
}
- if (!reMattable_.count(OrigVNI)) {
- DEBUG(dbgs() << "\tusing non-remat valno " << OrigVNI->id << ": "
- << UseIdx << '\t' << *MI);
- return false;
- }
- MachineInstr *OrigMI = lis_.getInstructionFromIndex(OrigVNI->def);
- if (!allUsesAvailableAt(OrigMI, OrigVNI->def, UseIdx)) {
+
+ LiveRangeEdit::Remat RM(OrigVNI);
+ if (!edit_->canRematerializeAt(RM, UseIdx, false, lis_)) {
usedValues_.insert(OrigVNI);
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 edit_->getReg(), 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(edit_->getReg(), &Ops);
if (Writes) {
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(Ops[i]);
@@ -210,61 +194,43 @@ bool InlineSpiller::reMaterializeFor(MachineBasicBlock::iterator MI) {
}
// Alocate a new register for the remat.
- unsigned NewVReg = mri_.createVirtualRegister(rc_);
- vrm_.grow();
- LiveInterval &NewLI = lis_.getOrCreateInterval(NewVReg);
+ LiveInterval &NewLI = edit_->create(mri_, 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 << '\n');
// 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() == edit_->getReg()) {
+ 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())
+ if (!edit_->anyRematerializable(lis_, tii_, aa_))
return;
- // Try to remat before all uses of li_->reg.
+ usedValues_.clear();
+
+ // Try to remat before all uses of edit_->getReg().
bool anyRemat = false;
for (MachineRegisterInfo::use_nodbg_iterator
- RI = mri_.use_nodbg_begin(li_->reg);
+ RI = mri_.use_nodbg_begin(edit_->getReg());
MachineInstr *MI = RI.skipInstruction();)
anyRemat |= reMaterializeFor(MI);
@@ -273,33 +239,35 @@ void InlineSpiller::reMaterializeAll() {
// Remove any values that were completely rematted.
bool anyRemoved = false;
- for (SmallPtrSet<VNInfo*, 8>::iterator I = reMattable_.begin(),
- E = reMattable_.end(); I != E; ++I) {
+ for (LiveInterval::vni_iterator I = edit_->getParent().vni_begin(),
+ E = edit_->getParent().vni_end(); I != E; ++I) {
VNInfo *VNI = *I;
- if (VNI->hasPHIKill() || usedValues_.count(VNI))
+ if (VNI->hasPHIKill() || !edit_->didRematerialize(VNI) ||
+ 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);
+ VNI->def = SlotIndex();
anyRemoved = true;
}
if (!anyRemoved)
return;
- // Removing values may cause debug uses where li_ is not live.
- for (MachineRegisterInfo::use_iterator RI = mri_.use_begin(li_->reg);
+ // Removing values may cause debug uses where parent is not live.
+ for (MachineRegisterInfo::use_iterator RI = mri_.use_begin(edit_->getReg());
MachineInstr *MI = RI.skipInstruction();) {
if (!MI->isDebugValue())
continue;
- // Try to preserve the debug value if li_ is live immediately after it.
+ // Try to preserve the debug value if parent 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));
+ SlotIndex Idx = lis_.getInstructionIndex(NextMI);
+ VNInfo *VNI = edit_->getParent().getVNInfoAt(Idx);
if (VNI && (VNI->hasPHIKill() || usedValues_.count(VNI)))
continue;
}
@@ -317,7 +285,7 @@ bool InlineSpiller::coalesceStackAccess(MachineInstr *MI) {
return false;
// We have a stack access. Is it the right register and slot?
- if (reg != li_->reg || FI != stackSlot_)
+ if (reg != edit_->getReg() || FI != stackSlot_)
return false;
DEBUG(dbgs() << "Coalescing stack access: " << *MI);
@@ -366,7 +334,7 @@ void InlineSpiller::insertReload(LiveInterval &NewLI,
SlotIndex LoadIdx = lis_.InsertMachineInstrInMaps(MI).getDefIndex();
vrm_.addSpillSlotUse(stackSlot_, MI);
DEBUG(dbgs() << "\treload: " << LoadIdx << '\t' << *MI);
- VNInfo *LoadVNI = NewLI.getNextValue(LoadIdx, 0, true,
+ VNInfo *LoadVNI = NewLI.getNextValue(LoadIdx, 0,
lis_.getVNInfoAllocator());
NewLI.addRange(LiveRange(LoadIdx, Idx, LoadVNI));
}
@@ -375,28 +343,39 @@ void InlineSpiller::insertReload(LiveInterval &NewLI,
void InlineSpiller::insertSpill(LiveInterval &NewLI,
MachineBasicBlock::iterator MI) {
MachineBasicBlock &MBB = *MI->getParent();
+
+ // Get the defined value. It could be an early clobber so keep the def index.
SlotIndex Idx = lis_.getInstructionIndex(MI).getDefIndex();
+ VNInfo *VNI = edit_->getParent().getVNInfoAt(Idx);
+ assert(VNI && VNI->def.getDefIndex() == Idx && "Inconsistent VNInfo");
+ Idx = VNI->def;
+
tii_.storeRegToStackSlot(MBB, ++MI, NewLI.reg, true, stackSlot_, rc_, &tri_);
--MI; // Point to store instruction.
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.");
+ const SmallVectorImpl<LiveInterval*> &spillIs) {
+ LiveRangeEdit edit(*li, newIntervals, spillIs);
+ spill(edit);
+ if (VerifySpills)
+ mf_.verify(&pass_);
+}
- li_ = li;
- newIntervals_ = &newIntervals;
- rc_ = mri_.getRegClass(li->reg);
- spillIs_ = &spillIs;
+void InlineSpiller::spill(LiveRangeEdit &edit) {
+ edit_ = &edit;
+ assert(!edit.getParent().isStackSlot() && "Trying to spill a stack slot.");
+ DEBUG(dbgs() << "Inline spilling "
+ << mri_.getRegClass(edit.getReg())->getName()
+ << ':' << edit.getParent() << "\n");
+ assert(edit.getParent().isSpillable() &&
+ "Attempting to spill already spilled value.");
if (split())
return;
@@ -404,15 +383,20 @@ void InlineSpiller::spill(LiveInterval *li,
reMaterializeAll();
// Remat may handle everything.
- if (li_->empty())
+ if (edit_->getParent().empty())
return;
- stackSlot_ = vrm_.getStackSlot(li->reg);
- if (stackSlot_ == VirtRegMap::NO_STACK_SLOT)
- stackSlot_ = vrm_.assignVirt2StackSlot(li->reg);
+ rc_ = mri_.getRegClass(edit.getReg());
+ stackSlot_ = vrm_.assignVirt2StackSlot(edit_->getReg());
+
+ // Update LiveStacks now that we are committed to spilling.
+ LiveInterval &stacklvr = lss_.getOrCreateInterval(stackSlot_, rc_);
+ assert(stacklvr.empty() && "Just created stack slot not empty");
+ stacklvr.getNextValue(SlotIndex(), 0, lss_.getVNInfoAllocator());
+ stacklvr.MergeRangesInAsValue(edit_->getParent(), stacklvr.getValNumInfo(0));
// Iterate over instructions using register.
- for (MachineRegisterInfo::reg_iterator RI = mri_.reg_begin(li->reg);
+ for (MachineRegisterInfo::reg_iterator RI = mri_.reg_begin(edit.getReg());
MachineInstr *MI = RI.skipInstruction();) {
// Debug values are not allowed to affect codegen.
@@ -440,7 +424,7 @@ void InlineSpiller::spill(LiveInterval *li,
// Analyze instruction.
bool Reads, Writes;
SmallVector<unsigned, 8> Ops;
- tie(Reads, Writes) = MI->readsWritesVirtualRegister(li->reg, &Ops);
+ tie(Reads, Writes) = MI->readsWritesVirtualRegister(edit.getReg(), &Ops);
// Attempt to fold memory ops.
if (foldMemoryOperand(MI, Ops))
@@ -448,9 +432,7 @@ void InlineSpiller::spill(LiveInterval *li,
// 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.create(mri_, lis_, vrm_);
NewLI.markNotSpillable();
if (Reads)
@@ -460,7 +442,7 @@ void InlineSpiller::spill(LiveInterval *li,
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();
@@ -475,6 +457,5 @@ void InlineSpiller::spill(LiveInterval *li,
insertSpill(NewLI, MI);
DEBUG(dbgs() << "\tinterval: " << NewLI << '\n');
- newIntervals.push_back(&NewLI);
}
}
generated by cgit v1.1 at 2025-08-25 08:00:50 +0000