//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "regalloc"
#include "RegisterCoalescer.h"
-#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/Format.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
#include <cmath>
using namespace llvm;
+#define DEBUG_TYPE "regalloc"
+
STATISTIC(numJoins , "Number of interval joins performed");
STATISTIC(numCrossRCs , "Number of cross class joins performed");
STATISTIC(numCommutes , "Number of instruction commuting performed");
AliasAnalysis *AA;
RegisterClassInfo RegClassInfo;
+ /// A LaneMask to remember on which subregister live ranges we need to call
+ /// shrinkToUses() later.
+ unsigned ShrinkMask;
+
+ /// True if the main range of the currently coalesced intervals should be
+ /// checked for smaller live intervals.
+ bool ShrinkMainRange;
+
/// \brief True if the coalescer should aggressively coalesce global copies
/// in favor of keeping local copies.
bool JoinGlobalCopies;
/// blocks exclusively containing copies.
bool JoinSplitEdges;
- /// WorkList - Copy instructions yet to be coalesced.
+ /// Copy instructions yet to be coalesced.
SmallVector<MachineInstr*, 8> WorkList;
SmallVector<MachineInstr*, 8> LocalWorkList;
- /// ErasedInstrs - Set of instruction pointers that have been erased, and
+ /// Set of instruction pointers that have been erased, and
/// that may be present in WorkList.
SmallPtrSet<MachineInstr*, 8> ErasedInstrs;
void eliminateDeadDefs();
/// LiveRangeEdit callback.
- void LRE_WillEraseInstruction(MachineInstr *MI);
+ void LRE_WillEraseInstruction(MachineInstr *MI) override;
- /// coalesceLocals - coalesce the LocalWorkList.
+ /// Coalesce the LocalWorkList.
void coalesceLocals();
- /// joinAllIntervals - join compatible live intervals
+ /// Join compatible live intervals
void joinAllIntervals();
- /// copyCoalesceInMBB - Coalesce copies in the specified MBB, putting
+ /// Coalesce copies in the specified MBB, putting
/// copies that cannot yet be coalesced into WorkList.
void copyCoalesceInMBB(MachineBasicBlock *MBB);
- /// copyCoalesceWorkList - Try to coalesce all copies in CurrList. Return
+ /// Try to coalesce all copies in CurrList. Return
/// true if any progress was made.
bool copyCoalesceWorkList(MutableArrayRef<MachineInstr*> CurrList);
- /// joinCopy - Attempt to join intervals corresponding to SrcReg/DstReg,
+ /// Attempt to join intervals corresponding to SrcReg/DstReg,
/// which are the src/dst of the copy instruction CopyMI. This returns
/// true if the copy was successfully coalesced away. If it is not
/// currently possible to coalesce this interval, but it may be possible if
/// 'Again'.
bool joinCopy(MachineInstr *TheCopy, bool &Again);
- /// joinIntervals - Attempt to join these two intervals. On failure, this
+ /// Attempt to join these two intervals. On failure, this
/// returns false. The output "SrcInt" will not have been modified, so we
/// can use this information below to update aliases.
bool joinIntervals(CoalescerPair &CP);
/// Attempt joining with a reserved physreg.
bool joinReservedPhysReg(CoalescerPair &CP);
- /// adjustCopiesBackFrom - We found a non-trivially-coalescable copy. If
+ /// Add the LiveRange @p ToMerge as a subregister liverange of @p LI.
+ /// Subranges in @p LI which only partially interfere with the desired
+ /// LaneMask are split as necessary. @p LaneMask are the lanes that
+ /// @p ToMerge will occupy in the coalescer register. @p LI has its subrange
+ /// lanemasks already adjusted to the coalesced register.
+ void mergeSubRangeInto(LiveInterval &LI, const LiveRange &ToMerge,
+ unsigned LaneMask, CoalescerPair &CP);
+
+ /// Join the liveranges of two subregisters. Joins @p RRange into
+ /// @p LRange, @p RRange may be invalid afterwards.
+ void joinSubRegRanges(LiveRange &LRange, LiveRange &RRange,
+ unsigned LaneMask, const CoalescerPair &CP);
+
+ /// We found a non-trivially-coalescable copy. If
/// the source value number is defined by a copy from the destination reg
/// see if we can merge these two destination reg valno# into a single
/// value number, eliminating a copy.
bool adjustCopiesBackFrom(const CoalescerPair &CP, MachineInstr *CopyMI);
- /// hasOtherReachingDefs - Return true if there are definitions of IntB
+ /// Return true if there are definitions of IntB
/// other than BValNo val# that can reach uses of AValno val# of IntA.
bool hasOtherReachingDefs(LiveInterval &IntA, LiveInterval &IntB,
VNInfo *AValNo, VNInfo *BValNo);
- /// removeCopyByCommutingDef - We found a non-trivially-coalescable copy.
+ /// We found a non-trivially-coalescable copy.
/// If the source value number is defined by a commutable instruction and
/// its other operand is coalesced to the copy dest register, see if we
/// can transform the copy into a noop by commuting the definition.
bool removeCopyByCommutingDef(const CoalescerPair &CP,MachineInstr *CopyMI);
- /// reMaterializeTrivialDef - If the source of a copy is defined by a
+ /// If the source of a copy is defined by a
/// trivial computation, replace the copy by rematerialize the definition.
bool reMaterializeTrivialDef(CoalescerPair &CP, MachineInstr *CopyMI,
bool &IsDefCopy);
- /// canJoinPhys - Return true if a physreg copy should be joined.
+ /// Return true if a physreg copy should be joined.
bool canJoinPhys(const CoalescerPair &CP);
- /// updateRegDefsUses - Replace all defs and uses of SrcReg to DstReg and
+ /// Replace all defs and uses of SrcReg to DstReg and
/// update the subregister number if it is not zero. If DstReg is a
/// physical register and the existing subregister number of the def / use
/// being updated is not zero, make sure to set it to the correct physical
/// subregister.
void updateRegDefsUses(unsigned SrcReg, unsigned DstReg, unsigned SubIdx);
- /// eliminateUndefCopy - Handle copies of undef values.
- bool eliminateUndefCopy(MachineInstr *CopyMI, const CoalescerPair &CP);
+ /// Handle copies of undef values.
+ bool eliminateUndefCopy(MachineInstr *CopyMI);
public:
static char ID; // Class identification, replacement for typeinfo
initializeRegisterCoalescerPass(*PassRegistry::getPassRegistry());
}
- virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
- virtual void releaseMemory();
+ void releaseMemory() override;
- /// runOnMachineFunction - pass entry point
- virtual bool runOnMachineFunction(MachineFunction&);
+ /// This is the pass entry point.
+ bool runOnMachineFunction(MachineFunction&) override;
- /// print - Implement the dump method.
- virtual void print(raw_ostream &O, const Module* = 0) const;
+ /// Implement the dump method.
+ void print(raw_ostream &O, const Module* = nullptr) const override;
};
} /// end anonymous namespace
if (MBB->pred_size() != 1 || MBB->succ_size() != 1)
return false;
- for (MachineBasicBlock::const_iterator MII = MBB->begin(), E = MBB->end();
- MII != E; ++MII) {
- if (!MII->isCopyLike() && !MII->isUnconditionalBranch())
+ for (const auto &MI : *MBB) {
+ if (!MI.isCopyLike() && !MI.isUnconditionalBranch())
return false;
}
return true;
bool CoalescerPair::setRegisters(const MachineInstr *MI) {
SrcReg = DstReg = 0;
SrcIdx = DstIdx = 0;
- NewRC = 0;
+ NewRC = nullptr;
Flipped = CrossClass = false;
unsigned Src, Dst, SrcSub, DstSub;
if (SrcSub) {
Dst = TRI.getMatchingSuperReg(Dst, SrcSub, MRI.getRegClass(Src));
if (!Dst) return false;
- SrcSub = 0;
} else if (!MRI.getRegClass(Src)->contains(Dst)) {
return false;
}
void RegisterCoalescer::eliminateDeadDefs() {
SmallVector<unsigned, 8> NewRegs;
- LiveRangeEdit(0, NewRegs, *MF, *LIS, 0, this).eliminateDeadDefs(DeadDefs);
+ LiveRangeEdit(nullptr, NewRegs, *MF, *LIS,
+ nullptr, this).eliminateDeadDefs(DeadDefs);
}
// Callback from eliminateDeadDefs().
ErasedInstrs.insert(MI);
}
-/// adjustCopiesBackFrom - We found a non-trivially-coalescable copy with IntA
+/// We found a non-trivially-coalescable copy with IntA
/// being the source and IntB being the dest, thus this defines a value number
/// in IntB. If the source value number (in IntA) is defined by a copy from B,
/// see if we can merge these two pieces of B into a single value number,
// Okay, merge "B1" into the same value number as "B0".
if (BValNo != ValS->valno)
IntB.MergeValueNumberInto(BValNo, ValS->valno);
+
+ // Do the same for the subregister segments.
+ for (LiveInterval::SubRange &S : IntB.subranges()) {
+ VNInfo *SubBValNo = S.getVNInfoAt(CopyIdx);
+ S.addSegment(LiveInterval::Segment(FillerStart, FillerEnd, SubBValNo));
+ VNInfo *SubValSNo = S.getVNInfoAt(AValNo->def.getPrevSlot());
+ if (SubBValNo != SubValSNo)
+ S.MergeValueNumberInto(SubBValNo, SubValSNo);
+ }
+
DEBUG(dbgs() << " result = " << IntB << '\n');
// If the source instruction was killing the source register before the
return true;
}
-/// hasOtherReachingDefs - Return true if there are definitions of IntB
+/// Return true if there are definitions of IntB
/// other than BValNo val# that can reach uses of AValno val# of IntA.
bool RegisterCoalescer::hasOtherReachingDefs(LiveInterval &IntA,
LiveInterval &IntB,
if (LIS->hasPHIKill(IntA, AValNo))
return true;
- for (LiveInterval::iterator AI = IntA.begin(), AE = IntA.end();
- AI != AE; ++AI) {
- if (AI->valno != AValNo) continue;
+ for (LiveRange::Segment &ASeg : IntA.segments) {
+ if (ASeg.valno != AValNo) continue;
LiveInterval::iterator BI =
- std::upper_bound(IntB.begin(), IntB.end(), AI->start);
+ std::upper_bound(IntB.begin(), IntB.end(), ASeg.start);
if (BI != IntB.begin())
--BI;
- for (; BI != IntB.end() && AI->end >= BI->start; ++BI) {
+ for (; BI != IntB.end() && ASeg.end >= BI->start; ++BI) {
if (BI->valno == BValNo)
continue;
- if (BI->start <= AI->start && BI->end > AI->start)
+ if (BI->start <= ASeg.start && BI->end > ASeg.start)
return true;
- if (BI->start > AI->start && BI->start < AI->end)
+ if (BI->start > ASeg.start && BI->start < ASeg.end)
return true;
}
}
return false;
}
-/// removeCopyByCommutingDef - We found a non-trivially-coalescable copy with
+/// Copy segements with value number @p SrcValNo from liverange @p Src to live
+/// range @Dst and use value number @p DstValNo there.
+static void addSegmentsWithValNo(LiveRange &Dst, VNInfo *DstValNo,
+ const LiveRange &Src, const VNInfo *SrcValNo)
+{
+ for (const LiveRange::Segment &S : Src.segments) {
+ if (S.valno != SrcValNo)
+ continue;
+ Dst.addSegment(LiveRange::Segment(S.start, S.end, DstValNo));
+ }
+}
+
+/// We found a non-trivially-coalescable copy with
/// IntA being the source and IntB being the dest, thus this defines a value
/// number in IntB. If the source value number (in IntA) is defined by a
/// commutable instruction and its other operand is coalesced to the copy dest
///
/// B2 = op B0 A2<kill>
/// ...
-/// B1 = B2 <- now an identify copy
+/// B1 = B2 <- now an identity copy
/// ...
/// = op B2 <- more uses
///
///
bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
MachineInstr *CopyMI) {
- assert (!CP.isPhys());
-
- SlotIndex CopyIdx = LIS->getInstructionIndex(CopyMI).getRegSlot();
+ assert(!CP.isPhys());
LiveInterval &IntA =
- LIS->getInterval(CP.isFlipped() ? CP.getDstReg() : CP.getSrcReg());
+ LIS->getInterval(CP.isFlipped() ? CP.getDstReg() : CP.getSrcReg());
LiveInterval &IntB =
- LIS->getInterval(CP.isFlipped() ? CP.getSrcReg() : CP.getDstReg());
+ LIS->getInterval(CP.isFlipped() ? CP.getSrcReg() : CP.getDstReg());
// BValNo is a value number in B that is defined by a copy from A. 'B1' in
// the example above.
+ SlotIndex CopyIdx = LIS->getInstructionIndex(CopyMI).getRegSlot();
VNInfo *BValNo = IntB.getVNInfoAt(CopyIdx);
- if (!BValNo || BValNo->def != CopyIdx)
- return false;
+ assert(BValNo != nullptr && BValNo->def == CopyIdx);
// AValNo is the value number in A that defines the copy, A3 in the example.
VNInfo *AValNo = IntA.getVNInfoAt(CopyIdx.getRegSlot(true));
- assert(AValNo && "COPY source not live");
- if (AValNo->isPHIDef() || AValNo->isUnused())
+ assert(AValNo && !AValNo->isUnused() && "COPY source not live");
+ if (AValNo->isPHIDef())
return false;
MachineInstr *DefMI = LIS->getInstructionFromIndex(AValNo->def);
if (!DefMI)
MachineOperand &NewDstMO = DefMI->getOperand(NewDstIdx);
unsigned NewReg = NewDstMO.getReg();
- if (NewReg != IntB.reg || !LiveRangeQuery(IntB, AValNo->def).isKill())
+ if (NewReg != IntB.reg || !IntB.Query(AValNo->def).isKill())
return false;
// Make sure there are no other definitions of IntB that would reach the
// If some of the uses of IntA.reg is already coalesced away, return false.
// It's not possible to determine whether it's safe to perform the coalescing.
- for (MachineRegisterInfo::use_nodbg_iterator UI =
- MRI->use_nodbg_begin(IntA.reg),
- UE = MRI->use_nodbg_end(); UI != UE; ++UI) {
- MachineInstr *UseMI = &*UI;
+ for (MachineOperand &MO : MRI->use_nodbg_operands(IntA.reg)) {
+ MachineInstr *UseMI = MO.getParent();
+ unsigned OpNo = &MO - &UseMI->getOperand(0);
SlotIndex UseIdx = LIS->getInstructionIndex(UseMI);
LiveInterval::iterator US = IntA.FindSegmentContaining(UseIdx);
if (US == IntA.end() || US->valno != AValNo)
continue;
// If this use is tied to a def, we can't rewrite the register.
- if (UseMI->isRegTiedToDefOperand(UI.getOperandNo()))
+ if (UseMI->isRegTiedToDefOperand(OpNo))
return false;
}
MBB->insert(Pos, NewMI);
MBB->erase(DefMI);
}
- unsigned OpIdx = NewMI->findRegisterUseOperandIdx(IntA.reg, false);
- NewMI->getOperand(OpIdx).setIsKill();
// If ALR and BLR overlaps and end of BLR extends beyond end of ALR, e.g.
// A = or A, B
// Update uses of IntA of the specific Val# with IntB.
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(IntA.reg),
- UE = MRI->use_end(); UI != UE;) {
- MachineOperand &UseMO = UI.getOperand();
- MachineInstr *UseMI = &*UI;
+ UE = MRI->use_end();
+ UI != UE; /* ++UI is below because of possible MI removal */) {
+ MachineOperand &UseMO = *UI;
++UI;
+ if (UseMO.isUndef())
+ continue;
+ MachineInstr *UseMI = UseMO.getParent();
if (UseMI->isDebugValue()) {
// FIXME These don't have an instruction index. Not clear we have enough
// info to decide whether to do this replacement or not. For now do it.
}
SlotIndex UseIdx = LIS->getInstructionIndex(UseMI).getRegSlot(true);
LiveInterval::iterator US = IntA.FindSegmentContaining(UseIdx);
- if (US == IntA.end() || US->valno != AValNo)
+ assert(US != IntA.end() && "Use must be live");
+ if (US->valno != AValNo)
continue;
// Kill flags are no longer accurate. They are recomputed after RA.
UseMO.setIsKill(false);
DEBUG(dbgs() << "\t\tnoop: " << DefIdx << '\t' << *UseMI);
assert(DVNI->def == DefIdx);
BValNo = IntB.MergeValueNumberInto(BValNo, DVNI);
+ for (LiveInterval::SubRange &S : IntB.subranges()) {
+ VNInfo *SubDVNI = S.getVNInfoAt(DefIdx);
+ if (!SubDVNI)
+ continue;
+ VNInfo *SubBValNo = S.getVNInfoAt(CopyIdx);
+ assert(SubBValNo->def == CopyIdx);
+ VNInfo *Merged = S.MergeValueNumberInto(SubBValNo, SubDVNI);
+ Merged->def = CopyIdx;
+ }
+
ErasedInstrs.insert(UseMI);
LIS->RemoveMachineInstrFromMaps(UseMI);
UseMI->eraseFromParent();
// Extend BValNo by merging in IntA live segments of AValNo. Val# definition
// is updated.
- VNInfo *ValNo = BValNo;
- ValNo->def = AValNo->def;
- for (LiveInterval::iterator AI = IntA.begin(), AE = IntA.end();
- AI != AE; ++AI) {
- if (AI->valno != AValNo) continue;
- IntB.addSegment(LiveInterval::Segment(AI->start, AI->end, ValNo));
+ BumpPtrAllocator &Allocator = LIS->getVNInfoAllocator();
+ if (IntB.hasSubRanges()) {
+ if (!IntA.hasSubRanges()) {
+ unsigned Mask = MRI->getMaxLaneMaskForVReg(IntA.reg);
+ IntA.createSubRangeFrom(Allocator, Mask, IntA);
+ }
+ SlotIndex AIdx = CopyIdx.getRegSlot(true);
+ for (LiveInterval::SubRange &SA : IntA.subranges()) {
+ VNInfo *ASubValNo = SA.getVNInfoAt(AIdx);
+ assert(ASubValNo != nullptr);
+
+ unsigned AMask = SA.LaneMask;
+ for (LiveInterval::SubRange &SB : IntB.subranges()) {
+ unsigned BMask = SB.LaneMask;
+ unsigned Common = BMask & AMask;
+ if (Common == 0)
+ continue;
+
+ DEBUG(
+ dbgs() << format("\t\tCopy+Merge %04X into %04X\n", BMask, Common));
+ unsigned BRest = BMask & ~AMask;
+ LiveInterval::SubRange *CommonRange;
+ if (BRest != 0) {
+ SB.LaneMask = BRest;
+ DEBUG(dbgs() << format("\t\tReduce Lane to %04X\n", BRest));
+ // Duplicate SubRange for newly merged common stuff.
+ CommonRange = IntB.createSubRangeFrom(Allocator, Common, SB);
+ } else {
+ // We van reuse the L SubRange.
+ SB.LaneMask = Common;
+ CommonRange = &SB;
+ }
+ LiveRange RangeCopy(SB, Allocator);
+
+ VNInfo *BSubValNo = CommonRange->getVNInfoAt(CopyIdx);
+ assert(BSubValNo->def == CopyIdx);
+ BSubValNo->def = ASubValNo->def;
+ addSegmentsWithValNo(*CommonRange, BSubValNo, SA, ASubValNo);
+ AMask &= ~BMask;
+ }
+ if (AMask != 0) {
+ DEBUG(dbgs() << format("\t\tNew Lane %04X\n", AMask));
+ LiveRange *NewRange = IntB.createSubRange(Allocator, AMask);
+ VNInfo *BSubValNo = NewRange->getNextValue(CopyIdx, Allocator);
+ addSegmentsWithValNo(*NewRange, BSubValNo, SA, ASubValNo);
+ }
+ SA.removeValNo(ASubValNo);
+ }
}
+
+ BValNo->def = AValNo->def;
+ addSegmentsWithValNo(IntB, BValNo, IntA, AValNo);
DEBUG(dbgs() << "\t\textended: " << IntB << '\n');
IntA.removeValNo(AValNo);
+ // Remove valuenos in subranges (the A+B have subranges case has already been
+ // handled above)
+ if (!IntB.hasSubRanges()) {
+ SlotIndex AIdx = CopyIdx.getRegSlot(true);
+ for (LiveInterval::SubRange &SA : IntA.subranges()) {
+ VNInfo *ASubValNo = SA.getVNInfoAt(AIdx);
+ assert(ASubValNo != nullptr);
+ SA.removeValNo(ASubValNo);
+ }
+ }
DEBUG(dbgs() << "\t\ttrimmed: " << IntA << '\n');
++numCommutes;
return true;
}
-/// reMaterializeTrivialDef - If the source of a copy is defined by a trivial
+/// If the source of a copy is defined by a trivial
/// computation, replace the copy by rematerialize the definition.
bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
MachineInstr *CopyMI,
LiveInterval &SrcInt = LIS->getInterval(SrcReg);
SlotIndex CopyIdx = LIS->getInstructionIndex(CopyMI);
- VNInfo *ValNo = LiveRangeQuery(SrcInt, CopyIdx).valueIn();
+ VNInfo *ValNo = SrcInt.Query(CopyIdx).valueIn();
assert(ValNo && "CopyMI input register not live");
if (ValNo->isPHIDef() || ValNo->isUnused())
return false;
IsDefCopy = true;
return false;
}
- if (!DefMI->isAsCheapAsAMove())
+ if (!TII->isAsCheapAsAMove(DefMI))
return false;
if (!TII->isTriviallyReMaterializable(DefMI, AA))
return false;
if (DstOperand.getSubReg() && !DstOperand.isUndef())
return false;
+ // If both SrcIdx and DstIdx are set, correct rematerialization would widen
+ // the register substantially (beyond both source and dest size). This is bad
+ // for performance since it can cascade through a function, introducing many
+ // extra spills and fills (e.g. ARM can easily end up copying QQQQPR registers
+ // around after a few subreg copies).
+ if (SrcIdx && DstIdx)
+ return false;
+
const TargetRegisterClass *DefRC = TII->getRegClass(MCID, 0, TRI, *MF);
if (!DefMI->isImplicitDef()) {
if (TargetRegisterInfo::isPhysicalRegister(DstReg)) {
MachineBasicBlock *MBB = CopyMI->getParent();
MachineBasicBlock::iterator MII =
- llvm::next(MachineBasicBlock::iterator(CopyMI));
+ std::next(MachineBasicBlock::iterator(CopyMI));
TII->reMaterialize(*MBB, MII, DstReg, SrcIdx, DefMI, *TRI);
- MachineInstr *NewMI = prior(MII);
+ MachineInstr *NewMI = std::prev(MII);
LIS->ReplaceMachineInstrInMaps(CopyMI, NewMI);
CopyMI->eraseFromParent();
}
if (TargetRegisterInfo::isVirtualRegister(DstReg)) {
+ const TargetRegisterClass *NewRC = CP.getNewRC();
unsigned NewIdx = NewMI->getOperand(0).getSubReg();
- const TargetRegisterClass *RCForInst;
+
if (NewIdx)
- RCForInst = TRI->getMatchingSuperRegClass(MRI->getRegClass(DstReg), DefRC,
- NewIdx);
-
- if (MRI->constrainRegClass(DstReg, DefRC)) {
- // The materialized instruction is quite capable of setting DstReg
- // directly, but it may still have a now-trivial subregister index which
- // we should clear.
- NewMI->getOperand(0).setSubReg(0);
- } else if (NewIdx && RCForInst) {
- // The subreg index on NewMI is essential; we still have to make sure
- // DstReg:idx is in a class that NewMI can use.
- MRI->constrainRegClass(DstReg, RCForInst);
- } else {
- // DstReg is actually incompatible with NewMI, we have to move to a
- // super-reg's class. This could come from a sequence like:
- // GR32 = MOV32r0
- // GR8 = COPY GR32:sub_8
- MRI->setRegClass(DstReg, CP.getNewRC());
- updateRegDefsUses(DstReg, DstReg, DstIdx);
- NewMI->getOperand(0).setSubReg(
- TRI->composeSubRegIndices(SrcIdx, DefMI->getOperand(0).getSubReg()));
- }
+ NewRC = TRI->getMatchingSuperRegClass(NewRC, DefRC, NewIdx);
+ else
+ NewRC = TRI->getCommonSubClass(NewRC, DefRC);
+
+ assert(NewRC && "subreg chosen for remat incompatible with instruction");
+ MRI->setRegClass(DstReg, NewRC);
+
+ updateRegDefsUses(DstReg, DstReg, DstIdx);
+ NewMI->getOperand(0).setSubReg(NewIdx);
} else if (NewMI->getOperand(0).getReg() != CopyDstReg) {
// The New instruction may be defining a sub-register of what's actually
// been asked for. If so it must implicitly define the whole thing.
true /*IsDef*/,
true /*IsImp*/,
false /*IsKill*/));
+ // Record small dead def live-ranges for all the subregisters
+ // of the destination register.
+ // Otherwise, variables that live through may miss some
+ // interferences, thus creating invalid allocation.
+ // E.g., i386 code:
+ // vreg1 = somedef ; vreg1 GR8
+ // vreg2 = remat ; vreg2 GR32
+ // CL = COPY vreg2.sub_8bit
+ // = somedef vreg1 ; vreg1 GR8
+ // =>
+ // vreg1 = somedef ; vreg1 GR8
+ // ECX<def, dead> = remat ; CL<imp-def>
+ // = somedef vreg1 ; vreg1 GR8
+ // vreg1 will see the inteferences with CL but not with CH since
+ // no live-ranges would have been created for ECX.
+ // Fix that!
+ SlotIndex NewMIIdx = LIS->getInstructionIndex(NewMI);
+ for (MCRegUnitIterator Units(NewMI->getOperand(0).getReg(), TRI);
+ Units.isValid(); ++Units)
+ if (LiveRange *LR = LIS->getCachedRegUnit(*Units))
+ LR->createDeadDef(NewMIIdx.getRegSlot(), LIS->getVNInfoAllocator());
}
if (NewMI->getOperand(0).getSubReg())
for (unsigned i = 0, e = NewMIImplDefs.size(); i != e; ++i) {
unsigned Reg = NewMIImplDefs[i];
for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units)
- if (LiveInterval *LI = LIS->getCachedRegUnit(*Units))
- LI->createDeadDef(NewMIIdx.getRegSlot(), LIS->getVNInfoAllocator());
+ if (LiveRange *LR = LIS->getCachedRegUnit(*Units))
+ LR->createDeadDef(NewMIIdx.getRegSlot(), LIS->getVNInfoAllocator());
}
DEBUG(dbgs() << "Remat: " << *NewMI);
// The source interval can become smaller because we removed a use.
LIS->shrinkToUses(&SrcInt, &DeadDefs);
- if (!DeadDefs.empty())
+ if (!DeadDefs.empty()) {
+ // If the virtual SrcReg is completely eliminated, update all DBG_VALUEs
+ // to describe DstReg instead.
+ for (MachineOperand &UseMO : MRI->use_operands(SrcReg)) {
+ MachineInstr *UseMI = UseMO.getParent();
+ if (UseMI->isDebugValue()) {
+ UseMO.setReg(DstReg);
+ DEBUG(dbgs() << "\t\tupdated: " << *UseMI);
+ }
+ }
eliminateDeadDefs();
+ }
return true;
}
-/// eliminateUndefCopy - ProcessImpicitDefs may leave some copies of <undef>
+static void removeUndefValue(LiveRange &LR, SlotIndex At)
+{
+ VNInfo *VNInfo = LR.getVNInfoAt(At);
+ assert(VNInfo != nullptr && SlotIndex::isSameInstr(VNInfo->def, At));
+ LR.removeValNo(VNInfo);
+}
+
+/// ProcessImpicitDefs may leave some copies of <undef>
/// values, it only removes local variables. When we have a copy like:
///
/// %vreg1 = COPY %vreg2<undef>
///
/// We delete the copy and remove the corresponding value number from %vreg1.
/// Any uses of that value number are marked as <undef>.
-bool RegisterCoalescer::eliminateUndefCopy(MachineInstr *CopyMI,
- const CoalescerPair &CP) {
+bool RegisterCoalescer::eliminateUndefCopy(MachineInstr *CopyMI) {
+ // Note that we do not query CoalescerPair here but redo isMoveInstr as the
+ // CoalescerPair may have a new register class with adjusted subreg indices
+ // at this point.
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ isMoveInstr(*TRI, CopyMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx);
+
SlotIndex Idx = LIS->getInstructionIndex(CopyMI);
- LiveInterval *SrcInt = &LIS->getInterval(CP.getSrcReg());
- if (SrcInt->liveAt(Idx))
- return false;
- LiveInterval *DstInt = &LIS->getInterval(CP.getDstReg());
- if (DstInt->liveAt(Idx))
+ const LiveInterval &SrcLI = LIS->getInterval(SrcReg);
+ // CopyMI is undef iff SrcReg is not live before the instruction.
+ if (SrcSubIdx != 0 && SrcLI.hasSubRanges()) {
+ unsigned SrcMask = TRI->getSubRegIndexLaneMask(SrcSubIdx);
+ for (const LiveInterval::SubRange &SR : SrcLI.subranges()) {
+ if ((SR.LaneMask & SrcMask) == 0)
+ continue;
+ if (SR.liveAt(Idx))
+ return false;
+ }
+ } else if (SrcLI.liveAt(Idx))
return false;
- // No intervals are live-in to CopyMI - it is undef.
- if (CP.isFlipped())
- DstInt = SrcInt;
- SrcInt = 0;
-
- VNInfo *DeadVNI = DstInt->getVNInfoAt(Idx.getRegSlot());
- assert(DeadVNI && "No value defined in DstInt");
- DstInt->removeValNo(DeadVNI);
-
- // Find new undef uses.
- for (MachineRegisterInfo::reg_nodbg_iterator
- I = MRI->reg_nodbg_begin(DstInt->reg), E = MRI->reg_nodbg_end();
- I != E; ++I) {
- MachineOperand &MO = I.getOperand();
- if (MO.isDef() || MO.isUndef())
+ DEBUG(dbgs() << "\tEliminating copy of <undef> value\n");
+
+ // Remove any DstReg segments starting at the instruction.
+ LiveInterval &DstLI = LIS->getInterval(DstReg);
+ unsigned DstMask = TRI->getSubRegIndexLaneMask(DstSubIdx);
+ SlotIndex RegIndex = Idx.getRegSlot();
+ for (LiveInterval::SubRange &SR : DstLI.subranges()) {
+ if ((SR.LaneMask & DstMask) == 0)
+ continue;
+ removeUndefValue(SR, RegIndex);
+
+ DstLI.removeEmptySubRanges();
+ }
+ // Remove value or merge with previous one in case of a subregister def.
+ if (VNInfo *PrevVNI = DstLI.getVNInfoAt(Idx)) {
+ VNInfo *VNInfo = DstLI.getVNInfoAt(RegIndex);
+ DstLI.MergeValueNumberInto(VNInfo, PrevVNI);
+ } else {
+ removeUndefValue(DstLI, RegIndex);
+ }
+
+ // Mark uses as undef.
+ for (MachineOperand &MO : MRI->reg_nodbg_operands(DstReg)) {
+ if (MO.isDef() /*|| MO.isUndef()*/)
continue;
- MachineInstr *MI = MO.getParent();
- SlotIndex Idx = LIS->getInstructionIndex(MI);
- if (DstInt->liveAt(Idx))
+ const MachineInstr &MI = *MO.getParent();
+ SlotIndex UseIdx = LIS->getInstructionIndex(&MI);
+ unsigned UseMask = TRI->getSubRegIndexLaneMask(MO.getSubReg());
+ bool isLive;
+ if (UseMask != ~0u && DstLI.hasSubRanges()) {
+ isLive = false;
+ for (const LiveInterval::SubRange &SR : DstLI.subranges()) {
+ if ((SR.LaneMask & UseMask) == 0)
+ continue;
+ if (SR.liveAt(UseIdx)) {
+ isLive = true;
+ break;
+ }
+ }
+ } else
+ isLive = DstLI.liveAt(UseIdx);
+ if (isLive)
continue;
MO.setIsUndef(true);
- DEBUG(dbgs() << "\tnew undef: " << Idx << '\t' << *MI);
+ DEBUG(dbgs() << "\tnew undef: " << UseIdx << '\t' << MI);
}
return true;
}
-/// updateRegDefsUses - Replace all defs and uses of SrcReg to DstReg and
-/// update the subregister number if it is not zero. If DstReg is a
-/// physical register and the existing subregister number of the def / use
-/// being updated is not zero, make sure to set it to the correct physical
-/// subregister.
+/// Replace all defs and uses of SrcReg to DstReg and update the subregister
+/// number if it is not zero. If DstReg is a physical register and the existing
+/// subregister number of the def / use being updated is not zero, make sure to
+/// set it to the correct physical subregister.
void RegisterCoalescer::updateRegDefsUses(unsigned SrcReg,
unsigned DstReg,
unsigned SubIdx) {
bool DstIsPhys = TargetRegisterInfo::isPhysicalRegister(DstReg);
- LiveInterval *DstInt = DstIsPhys ? 0 : &LIS->getInterval(DstReg);
+ LiveInterval *DstInt = DstIsPhys ? nullptr : &LIS->getInterval(DstReg);
SmallPtrSet<MachineInstr*, 8> Visited;
- for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(SrcReg);
- MachineInstr *UseMI = I.skipInstruction();) {
+ for (MachineRegisterInfo::reg_instr_iterator
+ I = MRI->reg_instr_begin(SrcReg), E = MRI->reg_instr_end();
+ I != E; ) {
+ MachineInstr *UseMI = &*(I++);
+
// Each instruction can only be rewritten once because sub-register
// composition is not always idempotent. When SrcReg != DstReg, rewriting
// the UseMI operands removes them from the SrcReg use-def chain, but when
// SrcReg is DstReg we could encounter UseMI twice if it has multiple
// operands mentioning the virtual register.
- if (SrcReg == DstReg && !Visited.insert(UseMI))
+ if (SrcReg == DstReg && !Visited.insert(UseMI).second)
continue;
SmallVector<unsigned,8> Ops;
bool Reads, Writes;
- tie(Reads, Writes) = UseMI->readsWritesVirtualRegister(SrcReg, &Ops);
+ std::tie(Reads, Writes) = UseMI->readsWritesVirtualRegister(SrcReg, &Ops);
// If SrcReg wasn't read, it may still be the case that DstReg is live-in
// because SrcReg is a sub-register.
if (SubIdx && MO.isDef())
MO.setIsUndef(!Reads);
+ // A subreg use of a partially undef (super) register may be a complete
+ // undef use now and then has to be marked that way.
+ if (SubIdx != 0 && MO.isUse() && MRI->tracksSubRegLiveness()) {
+ if (!DstInt->hasSubRanges()) {
+ BumpPtrAllocator &Allocator = LIS->getVNInfoAllocator();
+ unsigned Mask = MRI->getMaxLaneMaskForVReg(DstInt->reg);
+ DstInt->createSubRangeFrom(Allocator, Mask, *DstInt);
+ }
+ unsigned Mask = TRI->getSubRegIndexLaneMask(SubIdx);
+ bool IsUndef = true;
+ SlotIndex MIIdx = UseMI->isDebugValue()
+ ? LIS->getSlotIndexes()->getIndexBefore(UseMI)
+ : LIS->getInstructionIndex(UseMI);
+ SlotIndex UseIdx = MIIdx.getRegSlot(true);
+ for (LiveInterval::SubRange &S : DstInt->subranges()) {
+ if ((S.LaneMask & Mask) == 0)
+ continue;
+ if (S.liveAt(UseIdx)) {
+ IsUndef = false;
+ break;
+ }
+ }
+ if (IsUndef) {
+ MO.setIsUndef(true);
+ // We found out some subregister use is actually reading an undefined
+ // value. In some cases the whole vreg has become undefined at this
+ // point so we have to potentially shrink the main range if the
+ // use was ending a live segment there.
+ LiveQueryResult Q = DstInt->Query(MIIdx);
+ if (Q.valueOut() == nullptr)
+ ShrinkMainRange = true;
+ }
+ }
+
if (DstIsPhys)
MO.substPhysReg(DstReg, *TRI);
else
}
}
-/// canJoinPhys - Return true if a copy involving a physreg should be joined.
+/// Return true if a copy involving a physreg should be joined.
bool RegisterCoalescer::canJoinPhys(const CoalescerPair &CP) {
/// Always join simple intervals that are defined by a single copy from a
/// reserved register. This doesn't increase register pressure, so it is
return false;
}
-/// joinCopy - Attempt to join intervals corresponding to SrcReg/DstReg,
+/// Attempt to join intervals corresponding to SrcReg/DstReg,
/// which are the src/dst of the copy instruction CopyMI. This returns true
/// if the copy was successfully coalesced away. If it is not currently
/// possible to coalesce this interval, but it may be possible if other
return false;
}
+ if (CP.getNewRC()) {
+ auto SrcRC = MRI->getRegClass(CP.getSrcReg());
+ auto DstRC = MRI->getRegClass(CP.getDstReg());
+ unsigned SrcIdx = CP.getSrcIdx();
+ unsigned DstIdx = CP.getDstIdx();
+ if (CP.isFlipped()) {
+ std::swap(SrcIdx, DstIdx);
+ std::swap(SrcRC, DstRC);
+ }
+ if (!TRI->shouldCoalesce(CopyMI, SrcRC, SrcIdx, DstRC, DstIdx,
+ CP.getNewRC())) {
+ DEBUG(dbgs() << "\tSubtarget bailed on coalescing.\n");
+ return false;
+ }
+ }
+
// Dead code elimination. This really should be handled by MachineDCE, but
// sometimes dead copies slip through, and we can't generate invalid live
// ranges.
}
// Eliminate undefs.
- if (!CP.isPhys() && eliminateUndefCopy(CopyMI, CP)) {
- DEBUG(dbgs() << "\tEliminated copy of <undef> value.\n");
+ if (!CP.isPhys() && eliminateUndefCopy(CopyMI)) {
LIS->RemoveMachineInstrFromMaps(CopyMI);
CopyMI->eraseFromParent();
return false; // Not coalescable.
if (CP.getSrcReg() == CP.getDstReg()) {
LiveInterval &LI = LIS->getInterval(CP.getSrcReg());
DEBUG(dbgs() << "\tCopy already coalesced: " << LI << '\n');
- LiveRangeQuery LRQ(LI, LIS->getInstructionIndex(CopyMI));
+ const SlotIndex CopyIdx = LIS->getInstructionIndex(CopyMI);
+ LiveQueryResult LRQ = LI.Query(CopyIdx);
if (VNInfo *DefVNI = LRQ.valueDefined()) {
VNInfo *ReadVNI = LRQ.valueIn();
assert(ReadVNI && "No value before copy and no <undef> flag.");
assert(ReadVNI != DefVNI && "Cannot read and define the same value.");
LI.MergeValueNumberInto(DefVNI, ReadVNI);
+
+ // Process subregister liveranges.
+ for (LiveInterval::SubRange &S : LI.subranges()) {
+ LiveQueryResult SLRQ = S.Query(CopyIdx);
+ if (VNInfo *SDefVNI = SLRQ.valueDefined()) {
+ VNInfo *SReadVNI = SLRQ.valueIn();
+ S.MergeValueNumberInto(SDefVNI, SReadVNI);
+ }
+ }
DEBUG(dbgs() << "\tMerged values: " << LI << '\n');
}
LIS->RemoveMachineInstrFromMaps(CopyMI);
return false;
}
} else {
+ // When possible, let DstReg be the larger interval.
+ if (!CP.isPartial() && LIS->getInterval(CP.getSrcReg()).size() >
+ LIS->getInterval(CP.getDstReg()).size())
+ CP.flip();
+
DEBUG({
- dbgs() << "\tConsidering merging to " << CP.getNewRC()->getName()
- << " with ";
+ dbgs() << "\tConsidering merging to "
+ << TRI->getRegClassName(CP.getNewRC()) << " with ";
if (CP.getDstIdx() && CP.getSrcIdx())
dbgs() << PrintReg(CP.getDstReg()) << " in "
<< TRI->getSubRegIndexName(CP.getDstIdx()) << " and "
dbgs() << PrintReg(CP.getSrcReg(), TRI) << " in "
<< PrintReg(CP.getDstReg(), TRI, CP.getSrcIdx()) << '\n';
});
-
- // When possible, let DstReg be the larger interval.
- if (!CP.isPartial() && LIS->getInterval(CP.getSrcReg()).size() >
- LIS->getInterval(CP.getDstReg()).size())
- CP.flip();
}
+ ShrinkMask = 0;
+ ShrinkMainRange = false;
+
// Okay, attempt to join these two intervals. On failure, this returns false.
// Otherwise, if one of the intervals being joined is a physreg, this method
// always canonicalizes DstInt to be it. The output "SrcInt" will not have
updateRegDefsUses(CP.getDstReg(), CP.getDstReg(), CP.getDstIdx());
updateRegDefsUses(CP.getSrcReg(), CP.getDstReg(), CP.getSrcIdx());
+ // Shrink subregister ranges if necessary.
+ if (ShrinkMask != 0) {
+ LiveInterval &LI = LIS->getInterval(CP.getDstReg());
+ for (LiveInterval::SubRange &S : LI.subranges()) {
+ if ((S.LaneMask & ShrinkMask) == 0)
+ continue;
+ DEBUG(dbgs() << "Shrink LaneUses (Lane "
+ << format("%04X", S.LaneMask) << ")\n");
+ LIS->shrinkToUses(S, LI.reg);
+ }
+ }
+ if (ShrinkMainRange) {
+ LiveInterval &LI = LIS->getInterval(CP.getDstReg());
+ LIS->shrinkToUses(&LI);
+ }
+
// SrcReg is guaranteed to be the register whose live interval that is
// being merged.
LIS->removeInterval(CP.getSrcReg());
TRI->UpdateRegAllocHint(CP.getSrcReg(), CP.getDstReg(), *MF);
DEBUG({
- dbgs() << "\tJoined. Result = " << PrintReg(CP.getDstReg(), TRI);
- if (!CP.isPhys())
+ dbgs() << "\tSuccess: " << PrintReg(CP.getSrcReg(), TRI, CP.getSrcIdx())
+ << " -> " << PrintReg(CP.getDstReg(), TRI, CP.getDstIdx()) << '\n';
+ dbgs() << "\tResult = ";
+ if (CP.isPhys())
+ dbgs() << PrintReg(CP.getDstReg(), TRI);
+ else
dbgs() << LIS->getInterval(CP.getDstReg());
- dbgs() << '\n';
+ dbgs() << '\n';
});
++numJoins;
assert(CP.isPhys() && "Must be a physreg copy");
assert(MRI->isReserved(CP.getDstReg()) && "Not a reserved register");
LiveInterval &RHS = LIS->getInterval(CP.getSrcReg());
- DEBUG(dbgs() << "\t\tRHS = " << PrintReg(CP.getSrcReg()) << ' ' << RHS
- << '\n');
+ DEBUG(dbgs() << "\t\tRHS = " << RHS << '\n');
assert(CP.isFlipped() && RHS.containsOneValue() &&
"Invalid join with reserved register");
namespace {
/// Track information about values in a single virtual register about to be
/// joined. Objects of this class are always created in pairs - one for each
-/// side of the CoalescerPair.
+/// side of the CoalescerPair (or one for each lane of a side of the coalescer
+/// pair)
class JoinVals {
- LiveInterval &LI;
-
- // Location of this register in the final joined register.
- // Either CP.DstIdx or CP.SrcIdx.
- unsigned SubIdx;
+ /// Live range we work on.
+ LiveRange &LR;
+ /// (Main) register we work on.
+ const unsigned Reg;
+
+ // Reg (and therefore the values in this liverange) will end up as subregister
+ // SubIdx in the coalesced register. Either CP.DstIdx or CP.SrcIdx.
+ const unsigned SubIdx;
+ // The LaneMask that this liverange will occupy the coalesced register. May be
+ // smaller than the lanemask produced by SubIdx when merging subranges.
+ const unsigned LaneMask;
+
+ /// This is true when joining sub register ranges, false when joining main
+ /// ranges.
+ const bool SubRangeJoin;
+ /// Whether the current LiveInterval tracks subregister liveness.
+ const bool TrackSubRegLiveness;
// Values that will be present in the final live range.
SmallVectorImpl<VNInfo*> &NewVNInfo;
bool PrunedComputed;
Val() : Resolution(CR_Keep), WriteLanes(0), ValidLanes(0),
- RedefVNI(0), OtherVNI(0), ErasableImplicitDef(false),
+ RedefVNI(nullptr), OtherVNI(nullptr), ErasableImplicitDef(false),
Pruned(false), PrunedComputed(false) {}
bool isAnalyzed() const { return WriteLanes != 0; }
// One entry per value number in LI.
SmallVector<Val, 8> Vals;
- unsigned computeWriteLanes(const MachineInstr *DefMI, bool &Redef);
- VNInfo *stripCopies(VNInfo *VNI);
+ unsigned computeWriteLanes(const MachineInstr *DefMI, bool &Redef) const;
+ std::pair<const VNInfo*,unsigned> followCopyChain(const VNInfo *VNI) const;
+ bool valuesIdentical(VNInfo *Val0, VNInfo *Val1, const JoinVals &Other) const;
ConflictResolution analyzeValue(unsigned ValNo, JoinVals &Other);
void computeAssignment(unsigned ValNo, JoinVals &Other);
bool taintExtent(unsigned, unsigned, JoinVals&,
SmallVectorImpl<std::pair<SlotIndex, unsigned> >&);
- bool usesLanes(MachineInstr *MI, unsigned, unsigned, unsigned);
+ bool usesLanes(const MachineInstr *MI, unsigned, unsigned, unsigned) const;
bool isPrunedValue(unsigned ValNo, JoinVals &Other);
public:
- JoinVals(LiveInterval &li, unsigned subIdx,
- SmallVectorImpl<VNInfo*> &newVNInfo,
- const CoalescerPair &cp,
- LiveIntervals *lis,
- const TargetRegisterInfo *tri)
- : LI(li), SubIdx(subIdx), NewVNInfo(newVNInfo), CP(cp), LIS(lis),
- Indexes(LIS->getSlotIndexes()), TRI(tri),
- Assignments(LI.getNumValNums(), -1), Vals(LI.getNumValNums())
+ JoinVals(LiveRange &LR, unsigned Reg, unsigned SubIdx, unsigned LaneMask,
+ SmallVectorImpl<VNInfo*> &newVNInfo, const CoalescerPair &cp,
+ LiveIntervals *lis, const TargetRegisterInfo *TRI, bool SubRangeJoin,
+ bool TrackSubRegLiveness)
+ : LR(LR), Reg(Reg), SubIdx(SubIdx), LaneMask(LaneMask),
+ SubRangeJoin(SubRangeJoin), TrackSubRegLiveness(TrackSubRegLiveness),
+ NewVNInfo(newVNInfo), CP(cp), LIS(lis), Indexes(LIS->getSlotIndexes()),
+ TRI(TRI), Assignments(LR.getNumValNums(), -1), Vals(LR.getNumValNums())
{}
- /// Analyze defs in LI and compute a value mapping in NewVNInfo.
+ /// Analyze defs in LR and compute a value mapping in NewVNInfo.
/// Returns false if any conflicts were impossible to resolve.
bool mapValues(JoinVals &Other);
/// Returns false if any conflicts were impossible to resolve.
bool resolveConflicts(JoinVals &Other);
- /// Prune the live range of values in Other.LI where they would conflict with
- /// CR_Replace values in LI. Collect end points for restoring the live range
+ /// Prune the live range of values in Other.LR where they would conflict with
+ /// CR_Replace values in LR. Collect end points for restoring the live range
/// after joining.
- void pruneValues(JoinVals &Other, SmallVectorImpl<SlotIndex> &EndPoints);
+ void pruneValues(JoinVals &Other, SmallVectorImpl<SlotIndex> &EndPoints,
+ bool changeInstrs);
+
+ // Removes subranges starting at copies that get removed. This sometimes
+ // happens when undefined subranges are copied around. These ranges contain
+ // no usefull information and can be removed.
+ void pruneSubRegValues(LiveInterval &LI, unsigned &ShrinkMask);
/// Erase any machine instructions that have been coalesced away.
/// Add erased instructions to ErasedInstrs.
/// Add foreign virtual registers to ShrinkRegs if their live range ended at
/// the erased instrs.
- void eraseInstrs(SmallPtrSet<MachineInstr*, 8> &ErasedInstrs,
+ void eraseInstrs(SmallPtrSetImpl<MachineInstr*> &ErasedInstrs,
SmallVectorImpl<unsigned> &ShrinkRegs);
/// Get the value assignments suitable for passing to LiveInterval::join.
/// Compute the bitmask of lanes actually written by DefMI.
/// Set Redef if there are any partial register definitions that depend on the
/// previous value of the register.
-unsigned JoinVals::computeWriteLanes(const MachineInstr *DefMI, bool &Redef) {
+unsigned JoinVals::computeWriteLanes(const MachineInstr *DefMI, bool &Redef)
+ const {
unsigned L = 0;
for (ConstMIOperands MO(DefMI); MO.isValid(); ++MO) {
- if (!MO->isReg() || MO->getReg() != LI.reg || !MO->isDef())
+ if (!MO->isReg() || MO->getReg() != Reg || !MO->isDef())
continue;
L |= TRI->getSubRegIndexLaneMask(
TRI->composeSubRegIndices(SubIdx, MO->getSubReg()));
}
/// Find the ultimate value that VNI was copied from.
-VNInfo *JoinVals::stripCopies(VNInfo *VNI) {
+std::pair<const VNInfo*, unsigned> JoinVals::followCopyChain(
+ const VNInfo *VNI) const {
+ unsigned Reg = this->Reg;
+
while (!VNI->isPHIDef()) {
- MachineInstr *MI = Indexes->getInstructionFromIndex(VNI->def);
+ SlotIndex Def = VNI->def;
+ MachineInstr *MI = Indexes->getInstructionFromIndex(Def);
assert(MI && "No defining instruction");
if (!MI->isFullCopy())
+ return std::make_pair(VNI, Reg);
+ unsigned SrcReg = MI->getOperand(1).getReg();
+ if (!TargetRegisterInfo::isVirtualRegister(SrcReg))
+ return std::make_pair(VNI, Reg);
+
+ const LiveInterval &LI = LIS->getInterval(SrcReg);
+ const VNInfo *ValueIn;
+ // No subrange involved.
+ if (!SubRangeJoin || !LI.hasSubRanges()) {
+ LiveQueryResult LRQ = LI.Query(Def);
+ ValueIn = LRQ.valueIn();
+ } else {
+ // Query subranges. Pick the first matching one.
+ ValueIn = nullptr;
+ for (const LiveInterval::SubRange &S : LI.subranges()) {
+ // Transform lanemask to a mask in the joined live interval.
+ unsigned SMask = TRI->composeSubRegIndexLaneMask(SubIdx, S.LaneMask);
+ if ((SMask & LaneMask) == 0)
+ continue;
+ LiveQueryResult LRQ = S.Query(Def);
+ ValueIn = LRQ.valueIn();
+ break;
+ }
+ }
+ if (ValueIn == nullptr)
break;
- unsigned Reg = MI->getOperand(1).getReg();
- if (!TargetRegisterInfo::isVirtualRegister(Reg))
- break;
- LiveRangeQuery LRQ(LIS->getInterval(Reg), VNI->def);
- if (!LRQ.valueIn())
- break;
- VNI = LRQ.valueIn();
+ VNI = ValueIn;
+ Reg = SrcReg;
}
- return VNI;
+ return std::make_pair(VNI, Reg);
+}
+
+bool JoinVals::valuesIdentical(VNInfo *Value0, VNInfo *Value1,
+ const JoinVals &Other) const {
+ const VNInfo *Orig0;
+ unsigned Reg0;
+ std::tie(Orig0, Reg0) = followCopyChain(Value0);
+ if (Orig0 == Value1)
+ return true;
+
+ const VNInfo *Orig1;
+ unsigned Reg1;
+ std::tie(Orig1, Reg1) = Other.followCopyChain(Value1);
+
+ // The values are equal if they are defined at the same place and use the
+ // same register. Note that we cannot compare VNInfos directly as some of
+ // them might be from a copy created in mergeSubRangeInto() while the other
+ // is from the original LiveInterval.
+ return Orig0->def == Orig1->def && Reg0 == Reg1;
}
/// Analyze ValNo in this live range, and set all fields of Vals[ValNo].
JoinVals::analyzeValue(unsigned ValNo, JoinVals &Other) {
Val &V = Vals[ValNo];
assert(!V.isAnalyzed() && "Value has already been analyzed!");
- VNInfo *VNI = LI.getValNumInfo(ValNo);
+ VNInfo *VNI = LR.getValNumInfo(ValNo);
if (VNI->isUnused()) {
V.WriteLanes = ~0u;
return CR_Keep;
}
// Get the instruction defining this value, compute the lanes written.
- const MachineInstr *DefMI = 0;
+ const MachineInstr *DefMI = nullptr;
if (VNI->isPHIDef()) {
// Conservatively assume that all lanes in a PHI are valid.
- V.ValidLanes = V.WriteLanes = TRI->getSubRegIndexLaneMask(SubIdx);
+ unsigned Lanes = SubRangeJoin ? 1 : TRI->getSubRegIndexLaneMask(SubIdx);
+ V.ValidLanes = V.WriteLanes = Lanes;
} else {
DefMI = Indexes->getInstructionFromIndex(VNI->def);
- bool Redef = false;
- V.ValidLanes = V.WriteLanes = computeWriteLanes(DefMI, Redef);
-
- // If this is a read-modify-write instruction, there may be more valid
- // lanes than the ones written by this instruction.
- // This only covers partial redef operands. DefMI may have normal use
- // operands reading the register. They don't contribute valid lanes.
- //
- // This adds ssub1 to the set of valid lanes in %src:
- //
- // %src:ssub1<def> = FOO
- //
- // This leaves only ssub1 valid, making any other lanes undef:
- //
- // %src:ssub1<def,read-undef> = FOO %src:ssub2
- //
- // The <read-undef> flag on the def operand means that old lane values are
- // not important.
- if (Redef) {
- V.RedefVNI = LiveRangeQuery(LI, VNI->def).valueIn();
- assert(V.RedefVNI && "Instruction is reading nonexistent value");
- computeAssignment(V.RedefVNI->id, Other);
- V.ValidLanes |= Vals[V.RedefVNI->id].ValidLanes;
- }
+ assert(DefMI != nullptr);
+ if (SubRangeJoin) {
+ // We don't care about the lanes when joining subregister ranges.
+ V.ValidLanes = V.WriteLanes = 1;
+ } else {
+ bool Redef = false;
+ V.ValidLanes = V.WriteLanes = computeWriteLanes(DefMI, Redef);
+
+ // If this is a read-modify-write instruction, there may be more valid
+ // lanes than the ones written by this instruction.
+ // This only covers partial redef operands. DefMI may have normal use
+ // operands reading the register. They don't contribute valid lanes.
+ //
+ // This adds ssub1 to the set of valid lanes in %src:
+ //
+ // %src:ssub1<def> = FOO
+ //
+ // This leaves only ssub1 valid, making any other lanes undef:
+ //
+ // %src:ssub1<def,read-undef> = FOO %src:ssub2
+ //
+ // The <read-undef> flag on the def operand means that old lane values are
+ // not important.
+ if (Redef) {
+ V.RedefVNI = LR.Query(VNI->def).valueIn();
+ assert((TrackSubRegLiveness || V.RedefVNI) &&
+ "Instruction is reading nonexistent value");
+ if (V.RedefVNI != nullptr) {
+ computeAssignment(V.RedefVNI->id, Other);
+ V.ValidLanes |= Vals[V.RedefVNI->id].ValidLanes;
+ }
+ }
- // An IMPLICIT_DEF writes undef values.
- if (DefMI->isImplicitDef()) {
- // We normally expect IMPLICIT_DEF values to be live only until the end
- // of their block. If the value is really live longer and gets pruned in
- // another block, this flag is cleared again.
- V.ErasableImplicitDef = true;
- V.ValidLanes &= ~V.WriteLanes;
+ // An IMPLICIT_DEF writes undef values.
+ if (DefMI->isImplicitDef()) {
+ // We normally expect IMPLICIT_DEF values to be live only until the end
+ // of their block. If the value is really live longer and gets pruned in
+ // another block, this flag is cleared again.
+ V.ErasableImplicitDef = true;
+ V.ValidLanes &= ~V.WriteLanes;
+ }
}
}
// Find the value in Other that overlaps VNI->def, if any.
- LiveRangeQuery OtherLRQ(Other.LI, VNI->def);
+ LiveQueryResult OtherLRQ = Other.LR.Query(VNI->def);
// It is possible that both values are defined by the same instruction, or
// the values are PHIs defined in the same block. When that happens, the two
return CR_Replace;
// Check for simple erasable conflicts.
- if (DefMI->isImplicitDef())
+ if (DefMI->isImplicitDef()) {
+ // We need the def for the subregister if there is nothing else live at the
+ // subrange at this point.
+ if (TrackSubRegLiveness
+ && (V.WriteLanes & (OtherV.ValidLanes | OtherV.WriteLanes)) == 0)
+ return CR_Replace;
return CR_Erase;
+ }
// Include the non-conflict where DefMI is a coalescable copy that kills
// OtherVNI. We still want the copy erased and value numbers merged.
// %other = COPY %ext
// %this = COPY %ext <-- Erase this copy
//
- if (DefMI->isFullCopy() && !CP.isPartial() &&
- stripCopies(VNI) == stripCopies(V.OtherVNI))
+ if (DefMI->isFullCopy() && !CP.isPartial()
+ && valuesIdentical(VNI, V.OtherVNI, Other))
return CR_Erase;
// If the lanes written by this instruction were all undef in OtherVNI, it is
// VNI is clobbering live lanes in OtherVNI, but there is still the
// possibility that no instructions actually read the clobbered lanes.
// If we're clobbering all the lanes in OtherVNI, at least one must be read.
- // Otherwise Other.LI wouldn't be live here.
+ // Otherwise Other.RI wouldn't be live here.
if ((TRI->getSubRegIndexLaneMask(Other.SubIdx) & ~V.WriteLanes) == 0)
return CR_Impossible;
return CR_Unresolved;
}
-/// Compute the value assignment for ValNo in LI.
+/// Compute the value assignment for ValNo in RI.
/// This may be called recursively by analyzeValue(), but never for a ValNo on
/// the stack.
void JoinVals::computeAssignment(unsigned ValNo, JoinVals &Other) {
assert(V.OtherVNI && "OtherVNI not assigned, can't merge.");
assert(Other.Vals[V.OtherVNI->id].isAnalyzed() && "Missing recursion");
Assignments[ValNo] = Other.Assignments[V.OtherVNI->id];
- DEBUG(dbgs() << "\t\tmerge " << PrintReg(LI.reg) << ':' << ValNo << '@'
- << LI.getValNumInfo(ValNo)->def << " into "
- << PrintReg(Other.LI.reg) << ':' << V.OtherVNI->id << '@'
+ DEBUG(dbgs() << "\t\tmerge " << PrintReg(Reg) << ':' << ValNo << '@'
+ << LR.getValNumInfo(ValNo)->def << " into "
+ << PrintReg(Other.Reg) << ':' << V.OtherVNI->id << '@'
<< V.OtherVNI->def << " --> @"
<< NewVNInfo[Assignments[ValNo]]->def << '\n');
break;
case CR_Replace:
- case CR_Unresolved:
+ case CR_Unresolved: {
// The other value is going to be pruned if this join is successful.
assert(V.OtherVNI && "OtherVNI not assigned, can't prune");
- Other.Vals[V.OtherVNI->id].Pruned = true;
+ Val &OtherV = Other.Vals[V.OtherVNI->id];
+ // We cannot erase an IMPLICIT_DEF if we don't have valid values for all
+ // its lanes.
+ if ((OtherV.WriteLanes & ~V.ValidLanes) != 0 && TrackSubRegLiveness)
+ OtherV.ErasableImplicitDef = false;
+ OtherV.Pruned = true;
+ }
// Fall through.
default:
// This value number needs to go in the final joined live range.
Assignments[ValNo] = NewVNInfo.size();
- NewVNInfo.push_back(LI.getValNumInfo(ValNo));
+ NewVNInfo.push_back(LR.getValNumInfo(ValNo));
break;
}
}
bool JoinVals::mapValues(JoinVals &Other) {
- for (unsigned i = 0, e = LI.getNumValNums(); i != e; ++i) {
+ for (unsigned i = 0, e = LR.getNumValNums(); i != e; ++i) {
computeAssignment(i, Other);
if (Vals[i].Resolution == CR_Impossible) {
- DEBUG(dbgs() << "\t\tinterference at " << PrintReg(LI.reg) << ':' << i
- << '@' << LI.getValNumInfo(i)->def << '\n');
+ DEBUG(dbgs() << "\t\tinterference at " << PrintReg(Reg) << ':' << i
+ << '@' << LR.getValNumInfo(i)->def << '\n');
return false;
}
}
return true;
}
-/// Assuming ValNo is going to clobber some valid lanes in Other.LI, compute
+/// Assuming ValNo is going to clobber some valid lanes in Other.LR, compute
/// the extent of the tainted lanes in the block.
///
-/// Multiple values in Other.LI can be affected since partial redefinitions can
+/// Multiple values in Other.LR can be affected since partial redefinitions can
/// preserve previously tainted lanes.
///
/// 1 %dst = VLOAD <-- Define all lanes in %dst
bool JoinVals::
taintExtent(unsigned ValNo, unsigned TaintedLanes, JoinVals &Other,
SmallVectorImpl<std::pair<SlotIndex, unsigned> > &TaintExtent) {
- VNInfo *VNI = LI.getValNumInfo(ValNo);
+ VNInfo *VNI = LR.getValNumInfo(ValNo);
MachineBasicBlock *MBB = Indexes->getMBBFromIndex(VNI->def);
SlotIndex MBBEnd = Indexes->getMBBEndIdx(MBB);
- // Scan Other.LI from VNI.def to MBBEnd.
- LiveInterval::iterator OtherI = Other.LI.find(VNI->def);
- assert(OtherI != Other.LI.end() && "No conflict?");
+ // Scan Other.LR from VNI.def to MBBEnd.
+ LiveInterval::iterator OtherI = Other.LR.find(VNI->def);
+ assert(OtherI != Other.LR.end() && "No conflict?");
do {
// OtherI is pointing to a tainted value. Abort the join if the tainted
// lanes escape the block.
SlotIndex End = OtherI->end;
if (End >= MBBEnd) {
- DEBUG(dbgs() << "\t\ttaints global " << PrintReg(Other.LI.reg) << ':'
+ DEBUG(dbgs() << "\t\ttaints global " << PrintReg(Other.Reg) << ':'
<< OtherI->valno->id << '@' << OtherI->start << '\n');
return false;
}
- DEBUG(dbgs() << "\t\ttaints local " << PrintReg(Other.LI.reg) << ':'
+ DEBUG(dbgs() << "\t\ttaints local " << PrintReg(Other.Reg) << ':'
<< OtherI->valno->id << '@' << OtherI->start
<< " to " << End << '\n');
// A dead def is not a problem.
TaintExtent.push_back(std::make_pair(End, TaintedLanes));
// Check for another def in the MBB.
- if (++OtherI == Other.LI.end() || OtherI->start >= MBBEnd)
+ if (++OtherI == Other.LR.end() || OtherI->start >= MBBEnd)
break;
// Lanes written by the new def are no longer tainted.
/// Return true if MI uses any of the given Lanes from Reg.
/// This does not include partial redefinitions of Reg.
-bool JoinVals::usesLanes(MachineInstr *MI, unsigned Reg, unsigned SubIdx,
- unsigned Lanes) {
+bool JoinVals::usesLanes(const MachineInstr *MI, unsigned Reg, unsigned SubIdx,
+ unsigned Lanes) const {
if (MI->isDebugValue())
return false;
for (ConstMIOperands MO(MI); MO.isValid(); ++MO) {
}
bool JoinVals::resolveConflicts(JoinVals &Other) {
- for (unsigned i = 0, e = LI.getNumValNums(); i != e; ++i) {
+ for (unsigned i = 0, e = LR.getNumValNums(); i != e; ++i) {
Val &V = Vals[i];
assert (V.Resolution != CR_Impossible && "Unresolvable conflict");
if (V.Resolution != CR_Unresolved)
continue;
- DEBUG(dbgs() << "\t\tconflict at " << PrintReg(LI.reg) << ':' << i
- << '@' << LI.getValNumInfo(i)->def << '\n');
+ DEBUG(dbgs() << "\t\tconflict at " << PrintReg(Reg) << ':' << i
+ << '@' << LR.getValNumInfo(i)->def << '\n');
+ if (SubRangeJoin)
+ return false;
+
++NumLaneConflicts;
assert(V.OtherVNI && "Inconsistent conflict resolution.");
- VNInfo *VNI = LI.getValNumInfo(i);
+ VNInfo *VNI = LR.getValNumInfo(i);
const Val &OtherV = Other.Vals[V.OtherVNI->id];
// VNI is known to clobber some lanes in OtherVNI. If we go ahead with the
unsigned TaintNum = 0;
for(;;) {
assert(MI != MBB->end() && "Bad LastMI");
- if (usesLanes(MI, Other.LI.reg, Other.SubIdx, TaintedLanes)) {
+ if (usesLanes(MI, Other.Reg, Other.SubIdx, TaintedLanes)) {
DEBUG(dbgs() << "\t\ttainted lanes used by: " << *MI);
return false;
}
return true;
}
-// Determine if ValNo is a copy of a value number in LI or Other.LI that will
+// Determine if ValNo is a copy of a value number in LR or Other.LR that will
// be pruned:
//
// %dst = COPY %src
}
void JoinVals::pruneValues(JoinVals &Other,
- SmallVectorImpl<SlotIndex> &EndPoints) {
- for (unsigned i = 0, e = LI.getNumValNums(); i != e; ++i) {
- SlotIndex Def = LI.getValNumInfo(i)->def;
+ SmallVectorImpl<SlotIndex> &EndPoints,
+ bool changeInstrs) {
+ for (unsigned i = 0, e = LR.getNumValNums(); i != e; ++i) {
+ SlotIndex Def = LR.getValNumInfo(i)->def;
switch (Vals[i].Resolution) {
case CR_Keep:
break;
case CR_Replace: {
- // This value takes precedence over the value in Other.LI.
- LIS->pruneValue(&Other.LI, Def, &EndPoints);
+ // This value takes precedence over the value in Other.LR.
+ LIS->pruneValue(Other.LR, Def, &EndPoints);
// Check if we're replacing an IMPLICIT_DEF value. The IMPLICIT_DEF
// instructions are only inserted to provide a live-out value for PHI
// predecessors, so the instruction should simply go away once its value
bool EraseImpDef = OtherV.ErasableImplicitDef &&
OtherV.Resolution == CR_Keep;
if (!Def.isBlock()) {
- // Remove <def,read-undef> flags. This def is now a partial redef.
- // Also remove <def,dead> flags since the joined live range will
- // continue past this instruction.
- for (MIOperands MO(Indexes->getInstructionFromIndex(Def));
- MO.isValid(); ++MO)
- if (MO->isReg() && MO->isDef() && MO->getReg() == LI.reg) {
- MO->setIsUndef(EraseImpDef);
- MO->setIsDead(false);
+ if (changeInstrs) {
+ // Remove <def,read-undef> flags. This def is now a partial redef.
+ // Also remove <def,dead> flags since the joined live range will
+ // continue past this instruction.
+ for (MIOperands MO(Indexes->getInstructionFromIndex(Def));
+ MO.isValid(); ++MO) {
+ if (MO->isReg() && MO->isDef() && MO->getReg() == Reg) {
+ MO->setIsUndef(EraseImpDef);
+ MO->setIsDead(false);
+ }
}
+ }
// This value will reach instructions below, but we need to make sure
// the live range also reaches the instruction at Def.
if (!EraseImpDef)
EndPoints.push_back(Def);
}
- DEBUG(dbgs() << "\t\tpruned " << PrintReg(Other.LI.reg) << " at " << Def
- << ": " << Other.LI << '\n');
+ DEBUG(dbgs() << "\t\tpruned " << PrintReg(Other.Reg) << " at " << Def
+ << ": " << Other.LR << '\n');
break;
}
case CR_Erase:
case CR_Merge:
if (isPrunedValue(i, Other)) {
- // This value is ultimately a copy of a pruned value in LI or Other.LI.
+ // This value is ultimately a copy of a pruned value in LR or Other.LR.
// We can no longer trust the value mapping computed by
// computeAssignment(), the value that was originally copied could have
// been replaced.
- LIS->pruneValue(&LI, Def, &EndPoints);
- DEBUG(dbgs() << "\t\tpruned all of " << PrintReg(LI.reg) << " at "
- << Def << ": " << LI << '\n');
+ LIS->pruneValue(LR, Def, &EndPoints);
+ DEBUG(dbgs() << "\t\tpruned all of " << PrintReg(Reg) << " at "
+ << Def << ": " << LR << '\n');
}
break;
case CR_Unresolved:
}
}
-void JoinVals::eraseInstrs(SmallPtrSet<MachineInstr*, 8> &ErasedInstrs,
+void JoinVals::pruneSubRegValues(LiveInterval &LI, unsigned &ShrinkMask)
+{
+ // Look for values being erased.
+ bool DidPrune = false;
+ for (unsigned i = 0, e = LR.getNumValNums(); i != e; ++i) {
+ if (Vals[i].Resolution != CR_Erase)
+ continue;
+
+ // Check subranges at the point where the copy will be removed.
+ SlotIndex Def = LR.getValNumInfo(i)->def;
+ for (LiveInterval::SubRange &S : LI.subranges()) {
+ LiveQueryResult Q = S.Query(Def);
+
+ // If a subrange starts at the copy then an undefined value has been
+ // copied and we must remove that subrange value as well.
+ VNInfo *ValueOut = Q.valueOutOrDead();
+ if (ValueOut != nullptr && Q.valueIn() == nullptr) {
+ DEBUG(dbgs() << "\t\tPrune sublane " << format("%04X", S.LaneMask)
+ << " at " << Def << "\n");
+ LIS->pruneValue(S, Def, nullptr);
+ DidPrune = true;
+ // Mark value number as unused.
+ ValueOut->markUnused();
+ continue;
+ }
+ // If a subrange ends at the copy, then a value was copied but only
+ // partially used later. Shrink the subregister range apropriately.
+ if (Q.valueIn() != nullptr && Q.valueOut() == nullptr) {
+ DEBUG(dbgs() << "\t\tDead uses at sublane "
+ << format("%04X", S.LaneMask) << " at " << Def << "\n");
+ ShrinkMask |= S.LaneMask;
+ }
+ }
+ }
+ if (DidPrune)
+ LI.removeEmptySubRanges();
+}
+
+void JoinVals::eraseInstrs(SmallPtrSetImpl<MachineInstr*> &ErasedInstrs,
SmallVectorImpl<unsigned> &ShrinkRegs) {
- for (unsigned i = 0, e = LI.getNumValNums(); i != e; ++i) {
+ for (unsigned i = 0, e = LR.getNumValNums(); i != e; ++i) {
// Get the def location before markUnused() below invalidates it.
- SlotIndex Def = LI.getValNumInfo(i)->def;
+ SlotIndex Def = LR.getValNumInfo(i)->def;
switch (Vals[i].Resolution) {
case CR_Keep:
// If an IMPLICIT_DEF value is pruned, it doesn't serve a purpose any
// PHIElimination to guarantee that all PHI predecessors have a value.
if (!Vals[i].ErasableImplicitDef || !Vals[i].Pruned)
break;
- // Remove value number i from LI. Note that this VNInfo is still present
+ // Remove value number i from LR. Note that this VNInfo is still present
// in NewVNInfo, so it will appear as an unused value number in the final
// joined interval.
- LI.getValNumInfo(i)->markUnused();
- LI.removeValNo(LI.getValNumInfo(i));
- DEBUG(dbgs() << "\t\tremoved " << i << '@' << Def << ": " << LI << '\n');
+ LR.getValNumInfo(i)->markUnused();
+ LR.removeValNo(LR.getValNumInfo(i));
+ DEBUG(dbgs() << "\t\tremoved " << i << '@' << Def << ": " << LR << '\n');
// FALL THROUGH.
case CR_Erase: {
}
}
+void RegisterCoalescer::joinSubRegRanges(LiveRange &LRange, LiveRange &RRange,
+ unsigned LaneMask,
+ const CoalescerPair &CP) {
+ SmallVector<VNInfo*, 16> NewVNInfo;
+ JoinVals RHSVals(RRange, CP.getSrcReg(), CP.getSrcIdx(), LaneMask,
+ NewVNInfo, CP, LIS, TRI, true, true);
+ JoinVals LHSVals(LRange, CP.getDstReg(), CP.getDstIdx(), LaneMask,
+ NewVNInfo, CP, LIS, TRI, true, true);
+
+ /// Compute NewVNInfo and resolve conflicts (see also joinVirtRegs())
+ /// Conflicts should already be resolved so the mapping/resolution should
+ /// always succeed.
+ if (!LHSVals.mapValues(RHSVals) || !RHSVals.mapValues(LHSVals))
+ llvm_unreachable("Can't join subrange although main ranges are compatible");
+ if (!LHSVals.resolveConflicts(RHSVals) || !RHSVals.resolveConflicts(LHSVals))
+ llvm_unreachable("Can't join subrange although main ranges are compatible");
+
+ // The merging algorithm in LiveInterval::join() can't handle conflicting
+ // value mappings, so we need to remove any live ranges that overlap a
+ // CR_Replace resolution. Collect a set of end points that can be used to
+ // restore the live range after joining.
+ SmallVector<SlotIndex, 8> EndPoints;
+ LHSVals.pruneValues(RHSVals, EndPoints, false);
+ RHSVals.pruneValues(LHSVals, EndPoints, false);
+
+ LRange.verify();
+ RRange.verify();
+
+ // Join RRange into LHS.
+ LRange.join(RRange, LHSVals.getAssignments(), RHSVals.getAssignments(),
+ NewVNInfo);
+
+ DEBUG(dbgs() << "\t\tjoined lanes: " << LRange << "\n");
+ if (EndPoints.empty())
+ return;
+
+ // Recompute the parts of the live range we had to remove because of
+ // CR_Replace conflicts.
+ DEBUG(dbgs() << "\t\trestoring liveness to " << EndPoints.size()
+ << " points: " << LRange << '\n');
+ LIS->extendToIndices(LRange, EndPoints);
+}
+
+void RegisterCoalescer::mergeSubRangeInto(LiveInterval &LI,
+ const LiveRange &ToMerge,
+ unsigned LaneMask, CoalescerPair &CP) {
+ BumpPtrAllocator &Allocator = LIS->getVNInfoAllocator();
+ for (LiveInterval::SubRange &R : LI.subranges()) {
+ unsigned RMask = R.LaneMask;
+ // LaneMask of subregisters common to subrange R and ToMerge.
+ unsigned Common = RMask & LaneMask;
+ // There is nothing to do without common subregs.
+ if (Common == 0)
+ continue;
+
+ DEBUG(dbgs() << format("\t\tCopy+Merge %04X into %04X\n", RMask, Common));
+ // LaneMask of subregisters contained in the R range but not in ToMerge,
+ // they have to split into their own subrange.
+ unsigned LRest = RMask & ~LaneMask;
+ LiveInterval::SubRange *CommonRange;
+ if (LRest != 0) {
+ R.LaneMask = LRest;
+ DEBUG(dbgs() << format("\t\tReduce Lane to %04X\n", LRest));
+ // Duplicate SubRange for newly merged common stuff.
+ CommonRange = LI.createSubRangeFrom(Allocator, Common, R);
+ } else {
+ // Reuse the existing range.
+ R.LaneMask = Common;
+ CommonRange = &R;
+ }
+ LiveRange RangeCopy(ToMerge, Allocator);
+ joinSubRegRanges(*CommonRange, RangeCopy, Common, CP);
+ LaneMask &= ~RMask;
+ }
+
+ if (LaneMask != 0) {
+ DEBUG(dbgs() << format("\t\tNew Lane %04X\n", LaneMask));
+ LI.createSubRangeFrom(Allocator, LaneMask, ToMerge);
+ }
+}
+
bool RegisterCoalescer::joinVirtRegs(CoalescerPair &CP) {
SmallVector<VNInfo*, 16> NewVNInfo;
LiveInterval &RHS = LIS->getInterval(CP.getSrcReg());
LiveInterval &LHS = LIS->getInterval(CP.getDstReg());
- JoinVals RHSVals(RHS, CP.getSrcIdx(), NewVNInfo, CP, LIS, TRI);
- JoinVals LHSVals(LHS, CP.getDstIdx(), NewVNInfo, CP, LIS, TRI);
-
- DEBUG(dbgs() << "\t\tRHS = " << PrintReg(CP.getSrcReg()) << ' ' << RHS
- << "\n\t\tLHS = " << PrintReg(CP.getDstReg()) << ' ' << LHS
+ bool TrackSubRegLiveness = MRI->tracksSubRegLiveness();
+ JoinVals RHSVals(RHS, CP.getSrcReg(), CP.getSrcIdx(), 0, NewVNInfo, CP, LIS,
+ TRI, false, TrackSubRegLiveness);
+ JoinVals LHSVals(LHS, CP.getDstReg(), CP.getDstIdx(), 0, NewVNInfo, CP, LIS,
+ TRI, false, TrackSubRegLiveness);
+
+ DEBUG(dbgs() << "\t\tRHS = " << RHS
+ << "\n\t\tLHS = " << LHS
<< '\n');
// First compute NewVNInfo and the simple value mappings.
return false;
// All clear, the live ranges can be merged.
+ if (RHS.hasSubRanges() || LHS.hasSubRanges()) {
+ BumpPtrAllocator &Allocator = LIS->getVNInfoAllocator();
+
+ // Transform lanemasks from the LHS to masks in the coalesced register and
+ // create initial subranges if necessary.
+ unsigned DstIdx = CP.getDstIdx();
+ if (!LHS.hasSubRanges()) {
+ unsigned Mask = DstIdx == 0 ? CP.getNewRC()->getLaneMask()
+ : TRI->getSubRegIndexLaneMask(DstIdx);
+ // LHS must support subregs or we wouldn't be in this codepath.
+ assert(Mask != 0);
+ LHS.createSubRangeFrom(Allocator, Mask, LHS);
+ } else if (DstIdx != 0) {
+ // Transform LHS lanemasks to new register class if necessary.
+ for (LiveInterval::SubRange &R : LHS.subranges()) {
+ unsigned Mask = TRI->composeSubRegIndexLaneMask(DstIdx, R.LaneMask);
+ R.LaneMask = Mask;
+ }
+ }
+ DEBUG(dbgs() << "\t\tLHST = " << PrintReg(CP.getDstReg())
+ << ' ' << LHS << '\n');
+
+ // Determine lanemasks of RHS in the coalesced register and merge subranges.
+ unsigned SrcIdx = CP.getSrcIdx();
+ if (!RHS.hasSubRanges()) {
+ unsigned Mask = SrcIdx == 0 ? CP.getNewRC()->getLaneMask()
+ : TRI->getSubRegIndexLaneMask(SrcIdx);
+ mergeSubRangeInto(LHS, RHS, Mask, CP);
+ } else {
+ // Pair up subranges and merge.
+ for (LiveInterval::SubRange &R : RHS.subranges()) {
+ unsigned Mask = TRI->composeSubRegIndexLaneMask(SrcIdx, R.LaneMask);
+ mergeSubRangeInto(LHS, R, Mask, CP);
+ }
+ }
+
+ DEBUG(dbgs() << "\tJoined SubRanges " << LHS << "\n");
+
+ LHSVals.pruneSubRegValues(LHS, ShrinkMask);
+ RHSVals.pruneSubRegValues(LHS, ShrinkMask);
+ }
// The merging algorithm in LiveInterval::join() can't handle conflicting
// value mappings, so we need to remove any live ranges that overlap a
// CR_Replace resolution. Collect a set of end points that can be used to
// restore the live range after joining.
SmallVector<SlotIndex, 8> EndPoints;
- LHSVals.pruneValues(RHSVals, EndPoints);
- RHSVals.pruneValues(LHSVals, EndPoints);
+ LHSVals.pruneValues(RHSVals, EndPoints, true);
+ RHSVals.pruneValues(LHSVals, EndPoints, true);
// Erase COPY and IMPLICIT_DEF instructions. This may cause some external
// registers to require trimming.
MRI->clearKillFlags(LHS.reg);
MRI->clearKillFlags(RHS.reg);
- if (EndPoints.empty())
- return true;
+ if (!EndPoints.empty()) {
+ // Recompute the parts of the live range we had to remove because of
+ // CR_Replace conflicts.
+ DEBUG(dbgs() << "\t\trestoring liveness to " << EndPoints.size()
+ << " points: " << LHS << '\n');
+ LIS->extendToIndices((LiveRange&)LHS, EndPoints);
+ }
- // Recompute the parts of the live range we had to remove because of
- // CR_Replace conflicts.
- DEBUG(dbgs() << "\t\trestoring liveness to " << EndPoints.size()
- << " points: " << LHS << '\n');
- LIS->extendToIndices(&LHS, EndPoints);
return true;
}
-/// joinIntervals - Attempt to join these two intervals. On failure, this
-/// returns false.
+/// Attempt to join these two intervals. On failure, this returns false.
bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
return CP.isPhys() ? joinReservedPhysReg(CP) : joinVirtRegs(CP);
}
// Skip instruction pointers that have already been erased, for example by
// dead code elimination.
if (ErasedInstrs.erase(CurrList[i])) {
- CurrList[i] = 0;
+ CurrList[i] = nullptr;
continue;
}
bool Again = false;
bool Success = joinCopy(CurrList[i], Again);
Progress |= Success;
if (Success || !Again)
- CurrList[i] = 0;
+ CurrList[i] = nullptr;
}
return Progress;
}
CurrList(WorkList.begin() + PrevSize, WorkList.end());
if (copyCoalesceWorkList(CurrList))
WorkList.erase(std::remove(WorkList.begin() + PrevSize, WorkList.end(),
- (MachineInstr*)0), WorkList.end());
+ (MachineInstr*)nullptr), WorkList.end());
}
void RegisterCoalescer::coalesceLocals() {
MF = &fn;
MRI = &fn.getRegInfo();
TM = &fn.getTarget();
- TRI = TM->getRegisterInfo();
- TII = TM->getInstrInfo();
+ TRI = TM->getSubtargetImpl()->getRegisterInfo();
+ TII = TM->getSubtargetImpl()->getInstrInfo();
LIS = &getAnalysis<LiveIntervals>();
AA = &getAnalysis<AliasAnalysis>();
Loops = &getAnalysis<MachineLoopInfo>();
continue;
if (MRI->recomputeRegClass(Reg, *TM)) {
DEBUG(dbgs() << PrintReg(Reg) << " inflated to "
- << MRI->getRegClass(Reg)->getName() << '\n');
+ << TRI->getRegClassName(MRI->getRegClass(Reg)) << '\n');
+ LiveInterval &LI = LIS->getInterval(Reg);
+ unsigned MaxMask = MRI->getMaxLaneMaskForVReg(Reg);
+ if (MaxMask == 0) {
+ // If the inflated register class does not support subregisters anymore
+ // remove the subranges.
+ LI.clearSubRanges();
+ } else {
+ // If subranges are still supported, then the same subregs should still
+ // be supported.
+#ifndef NDEBUG
+ for (LiveInterval::SubRange &S : LI.subranges()) {
+ assert ((S.LaneMask & ~MaxMask) == 0);
+ }
+#endif
+ }
++NumInflated;
}
}
return true;
}
-/// print - Implement the dump method.
+/// Implement the dump method.
void RegisterCoalescer::print(raw_ostream &O, const Module* m) const {
LIS->print(O, m);
}
projects / oota-llvm.git / blobdiff