diff options
Diffstat (limited to 'lib/CodeGen/RegisterCoalescer.cpp')
-rw-r--r-- | lib/CodeGen/RegisterCoalescer.cpp | 50 |
1 files changed, 36 insertions, 14 deletions
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index 682c26c..5aaeb87 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -13,7 +13,6 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "regalloc" #include "RegisterCoalescer.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallSet.h" @@ -42,6 +41,8 @@ #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"); @@ -195,7 +196,7 @@ namespace { bool runOnMachineFunction(MachineFunction&) override; /// print - Implement the dump method. - void print(raw_ostream &O, const Module* = 0) const override; + void print(raw_ostream &O, const Module* = nullptr) const override; }; } /// end anonymous namespace @@ -240,9 +241,8 @@ static bool isSplitEdge(const MachineBasicBlock *MBB) { 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; @@ -251,7 +251,7 @@ static bool isSplitEdge(const MachineBasicBlock *MBB) { bool CoalescerPair::setRegisters(const MachineInstr *MI) { SrcReg = DstReg = 0; SrcIdx = DstIdx = 0; - NewRC = 0; + NewRC = nullptr; Flipped = CrossClass = false; unsigned Src, Dst, SrcSub, DstSub; @@ -397,7 +397,8 @@ void RegisterCoalescer::getAnalysisUsage(AnalysisUsage &AU) const { 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(). @@ -844,6 +845,27 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP, 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()) @@ -902,7 +924,7 @@ bool RegisterCoalescer::eliminateUndefCopy(MachineInstr *CopyMI, // No intervals are live-in to CopyMI - it is undef. if (CP.isFlipped()) DstInt = SrcInt; - SrcInt = 0; + SrcInt = nullptr; VNInfo *DeadVNI = DstInt->getVNInfoAt(Idx.getRegSlot()); assert(DeadVNI && "No value defined in DstInt"); @@ -931,7 +953,7 @@ 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_instr_iterator @@ -1355,7 +1377,7 @@ class JoinVals { 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; } @@ -1461,7 +1483,7 @@ JoinVals::analyzeValue(unsigned ValNo, JoinVals &Other) { } // 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); @@ -2085,14 +2107,14 @@ copyCoalesceWorkList(MutableArrayRef<MachineInstr*> CurrList) { // 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; } @@ -2132,7 +2154,7 @@ RegisterCoalescer::copyCoalesceInMBB(MachineBasicBlock *MBB) { 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() { |