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https://github.com/RPCS3/llvm-mirror.git
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4f8e5f73dc
Differential Revision: https://reviews.llvm.org/D90611
1735 lines
65 KiB
C++
1735 lines
65 KiB
C++
//===- LiveIntervals.cpp - Live Interval Analysis -------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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/// \file This file implements the LiveInterval analysis pass which is used
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/// by the Linear Scan Register allocator. This pass linearizes the
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/// basic blocks of the function in DFS order and computes live intervals for
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/// each virtual and physical register.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/LiveIntervals.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/iterator_range.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/CodeGen/LiveInterval.h"
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#include "llvm/CodeGen/LiveIntervalCalc.h"
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#include "llvm/CodeGen/LiveVariables.h"
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#include "llvm/CodeGen/MachineBasicBlock.h"
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#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineInstrBundle.h"
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#include "llvm/CodeGen/MachineOperand.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/SlotIndexes.h"
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#include "llvm/CodeGen/TargetRegisterInfo.h"
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#include "llvm/CodeGen/TargetSubtargetInfo.h"
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#include "llvm/CodeGen/VirtRegMap.h"
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#include "llvm/Config/llvm-config.h"
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#include "llvm/MC/LaneBitmask.h"
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#include "llvm/MC/MCRegisterInfo.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/BlockFrequency.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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#include <cassert>
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#include <cstdint>
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#include <iterator>
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#include <tuple>
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#include <utility>
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using namespace llvm;
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#define DEBUG_TYPE "regalloc"
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char LiveIntervals::ID = 0;
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char &llvm::LiveIntervalsID = LiveIntervals::ID;
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INITIALIZE_PASS_BEGIN(LiveIntervals, "liveintervals",
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"Live Interval Analysis", false, false)
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INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
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INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
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INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
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INITIALIZE_PASS_END(LiveIntervals, "liveintervals",
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"Live Interval Analysis", false, false)
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#ifndef NDEBUG
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static cl::opt<bool> EnablePrecomputePhysRegs(
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"precompute-phys-liveness", cl::Hidden,
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cl::desc("Eagerly compute live intervals for all physreg units."));
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#else
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static bool EnablePrecomputePhysRegs = false;
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#endif // NDEBUG
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namespace llvm {
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cl::opt<bool> UseSegmentSetForPhysRegs(
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"use-segment-set-for-physregs", cl::Hidden, cl::init(true),
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cl::desc(
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"Use segment set for the computation of the live ranges of physregs."));
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} // end namespace llvm
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void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesCFG();
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AU.addRequired<AAResultsWrapperPass>();
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AU.addPreserved<AAResultsWrapperPass>();
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AU.addPreserved<LiveVariables>();
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AU.addPreservedID(MachineLoopInfoID);
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AU.addRequiredTransitiveID(MachineDominatorsID);
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AU.addPreservedID(MachineDominatorsID);
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AU.addPreserved<SlotIndexes>();
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AU.addRequiredTransitive<SlotIndexes>();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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LiveIntervals::LiveIntervals() : MachineFunctionPass(ID) {
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initializeLiveIntervalsPass(*PassRegistry::getPassRegistry());
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}
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LiveIntervals::~LiveIntervals() { delete LICalc; }
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void LiveIntervals::releaseMemory() {
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// Free the live intervals themselves.
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for (unsigned i = 0, e = VirtRegIntervals.size(); i != e; ++i)
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delete VirtRegIntervals[Register::index2VirtReg(i)];
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VirtRegIntervals.clear();
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RegMaskSlots.clear();
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RegMaskBits.clear();
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RegMaskBlocks.clear();
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for (LiveRange *LR : RegUnitRanges)
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delete LR;
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RegUnitRanges.clear();
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// Release VNInfo memory regions, VNInfo objects don't need to be dtor'd.
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VNInfoAllocator.Reset();
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}
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bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
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MF = &fn;
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MRI = &MF->getRegInfo();
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TRI = MF->getSubtarget().getRegisterInfo();
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TII = MF->getSubtarget().getInstrInfo();
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AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
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Indexes = &getAnalysis<SlotIndexes>();
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DomTree = &getAnalysis<MachineDominatorTree>();
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if (!LICalc)
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LICalc = new LiveIntervalCalc();
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// Allocate space for all virtual registers.
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VirtRegIntervals.resize(MRI->getNumVirtRegs());
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computeVirtRegs();
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computeRegMasks();
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computeLiveInRegUnits();
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if (EnablePrecomputePhysRegs) {
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// For stress testing, precompute live ranges of all physical register
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// units, including reserved registers.
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for (unsigned i = 0, e = TRI->getNumRegUnits(); i != e; ++i)
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getRegUnit(i);
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}
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LLVM_DEBUG(dump());
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return true;
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}
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void LiveIntervals::print(raw_ostream &OS, const Module* ) const {
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OS << "********** INTERVALS **********\n";
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// Dump the regunits.
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for (unsigned Unit = 0, UnitE = RegUnitRanges.size(); Unit != UnitE; ++Unit)
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if (LiveRange *LR = RegUnitRanges[Unit])
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OS << printRegUnit(Unit, TRI) << ' ' << *LR << '\n';
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// Dump the virtregs.
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for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
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Register Reg = Register::index2VirtReg(i);
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if (hasInterval(Reg))
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OS << getInterval(Reg) << '\n';
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}
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OS << "RegMasks:";
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for (SlotIndex Idx : RegMaskSlots)
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OS << ' ' << Idx;
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OS << '\n';
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printInstrs(OS);
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}
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void LiveIntervals::printInstrs(raw_ostream &OS) const {
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OS << "********** MACHINEINSTRS **********\n";
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MF->print(OS, Indexes);
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}
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#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
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LLVM_DUMP_METHOD void LiveIntervals::dumpInstrs() const {
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printInstrs(dbgs());
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}
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#endif
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LiveInterval *LiveIntervals::createInterval(Register reg) {
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float Weight = Register::isPhysicalRegister(reg) ? huge_valf : 0.0F;
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return new LiveInterval(reg, Weight);
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}
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/// Compute the live interval of a virtual register, based on defs and uses.
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bool LiveIntervals::computeVirtRegInterval(LiveInterval &LI) {
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assert(LICalc && "LICalc not initialized.");
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assert(LI.empty() && "Should only compute empty intervals.");
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LICalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator());
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LICalc->calculate(LI, MRI->shouldTrackSubRegLiveness(LI.reg()));
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return computeDeadValues(LI, nullptr);
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}
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void LiveIntervals::computeVirtRegs() {
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for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
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Register Reg = Register::index2VirtReg(i);
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if (MRI->reg_nodbg_empty(Reg))
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continue;
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LiveInterval &LI = createEmptyInterval(Reg);
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bool NeedSplit = computeVirtRegInterval(LI);
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if (NeedSplit) {
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SmallVector<LiveInterval*, 8> SplitLIs;
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splitSeparateComponents(LI, SplitLIs);
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}
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}
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}
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void LiveIntervals::computeRegMasks() {
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RegMaskBlocks.resize(MF->getNumBlockIDs());
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// Find all instructions with regmask operands.
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for (const MachineBasicBlock &MBB : *MF) {
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std::pair<unsigned, unsigned> &RMB = RegMaskBlocks[MBB.getNumber()];
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RMB.first = RegMaskSlots.size();
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// Some block starts, such as EH funclets, create masks.
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if (const uint32_t *Mask = MBB.getBeginClobberMask(TRI)) {
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RegMaskSlots.push_back(Indexes->getMBBStartIdx(&MBB));
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RegMaskBits.push_back(Mask);
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}
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// Unwinders may clobber additional registers.
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// FIXME: This functionality can possibly be merged into
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// MachineBasicBlock::getBeginClobberMask().
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if (MBB.isEHPad())
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if (auto *Mask = TRI->getCustomEHPadPreservedMask(*MBB.getParent())) {
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RegMaskSlots.push_back(Indexes->getMBBStartIdx(&MBB));
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RegMaskBits.push_back(Mask);
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}
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for (const MachineInstr &MI : MBB) {
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for (const MachineOperand &MO : MI.operands()) {
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if (!MO.isRegMask())
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continue;
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RegMaskSlots.push_back(Indexes->getInstructionIndex(MI).getRegSlot());
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RegMaskBits.push_back(MO.getRegMask());
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}
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}
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// Some block ends, such as funclet returns, create masks. Put the mask on
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// the last instruction of the block, because MBB slot index intervals are
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// half-open.
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if (const uint32_t *Mask = MBB.getEndClobberMask(TRI)) {
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assert(!MBB.empty() && "empty return block?");
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RegMaskSlots.push_back(
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Indexes->getInstructionIndex(MBB.back()).getRegSlot());
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RegMaskBits.push_back(Mask);
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}
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// Compute the number of register mask instructions in this block.
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RMB.second = RegMaskSlots.size() - RMB.first;
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}
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}
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//===----------------------------------------------------------------------===//
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// Register Unit Liveness
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//===----------------------------------------------------------------------===//
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//
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// Fixed interference typically comes from ABI boundaries: Function arguments
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// and return values are passed in fixed registers, and so are exception
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// pointers entering landing pads. Certain instructions require values to be
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// present in specific registers. That is also represented through fixed
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// interference.
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//
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/// Compute the live range of a register unit, based on the uses and defs of
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/// aliasing registers. The range should be empty, or contain only dead
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/// phi-defs from ABI blocks.
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void LiveIntervals::computeRegUnitRange(LiveRange &LR, unsigned Unit) {
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assert(LICalc && "LICalc not initialized.");
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LICalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator());
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// The physregs aliasing Unit are the roots and their super-registers.
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// Create all values as dead defs before extending to uses. Note that roots
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// may share super-registers. That's OK because createDeadDefs() is
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// idempotent. It is very rare for a register unit to have multiple roots, so
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// uniquing super-registers is probably not worthwhile.
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bool IsReserved = false;
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for (MCRegUnitRootIterator Root(Unit, TRI); Root.isValid(); ++Root) {
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bool IsRootReserved = true;
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for (MCSuperRegIterator Super(*Root, TRI, /*IncludeSelf=*/true);
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Super.isValid(); ++Super) {
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MCRegister Reg = *Super;
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if (!MRI->reg_empty(Reg))
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LICalc->createDeadDefs(LR, Reg);
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// A register unit is considered reserved if all its roots and all their
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// super registers are reserved.
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if (!MRI->isReserved(Reg))
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IsRootReserved = false;
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}
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IsReserved |= IsRootReserved;
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}
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assert(IsReserved == MRI->isReservedRegUnit(Unit) &&
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"reserved computation mismatch");
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// Now extend LR to reach all uses.
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// Ignore uses of reserved registers. We only track defs of those.
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if (!IsReserved) {
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for (MCRegUnitRootIterator Root(Unit, TRI); Root.isValid(); ++Root) {
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for (MCSuperRegIterator Super(*Root, TRI, /*IncludeSelf=*/true);
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Super.isValid(); ++Super) {
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MCRegister Reg = *Super;
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if (!MRI->reg_empty(Reg))
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LICalc->extendToUses(LR, Reg);
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}
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}
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}
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// Flush the segment set to the segment vector.
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if (UseSegmentSetForPhysRegs)
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LR.flushSegmentSet();
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}
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/// Precompute the live ranges of any register units that are live-in to an ABI
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/// block somewhere. Register values can appear without a corresponding def when
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/// entering the entry block or a landing pad.
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void LiveIntervals::computeLiveInRegUnits() {
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RegUnitRanges.resize(TRI->getNumRegUnits());
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LLVM_DEBUG(dbgs() << "Computing live-in reg-units in ABI blocks.\n");
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// Keep track of the live range sets allocated.
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SmallVector<unsigned, 8> NewRanges;
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// Check all basic blocks for live-ins.
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for (const MachineBasicBlock &MBB : *MF) {
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// We only care about ABI blocks: Entry + landing pads.
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if ((&MBB != &MF->front() && !MBB.isEHPad()) || MBB.livein_empty())
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continue;
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// Create phi-defs at Begin for all live-in registers.
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SlotIndex Begin = Indexes->getMBBStartIdx(&MBB);
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LLVM_DEBUG(dbgs() << Begin << "\t" << printMBBReference(MBB));
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for (const auto &LI : MBB.liveins()) {
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for (MCRegUnitIterator Units(LI.PhysReg, TRI); Units.isValid(); ++Units) {
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unsigned Unit = *Units;
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LiveRange *LR = RegUnitRanges[Unit];
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if (!LR) {
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// Use segment set to speed-up initial computation of the live range.
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LR = RegUnitRanges[Unit] = new LiveRange(UseSegmentSetForPhysRegs);
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NewRanges.push_back(Unit);
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}
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VNInfo *VNI = LR->createDeadDef(Begin, getVNInfoAllocator());
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(void)VNI;
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LLVM_DEBUG(dbgs() << ' ' << printRegUnit(Unit, TRI) << '#' << VNI->id);
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}
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}
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LLVM_DEBUG(dbgs() << '\n');
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}
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LLVM_DEBUG(dbgs() << "Created " << NewRanges.size() << " new intervals.\n");
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// Compute the 'normal' part of the ranges.
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for (unsigned Unit : NewRanges)
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computeRegUnitRange(*RegUnitRanges[Unit], Unit);
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}
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static void createSegmentsForValues(LiveRange &LR,
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iterator_range<LiveInterval::vni_iterator> VNIs) {
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for (VNInfo *VNI : VNIs) {
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if (VNI->isUnused())
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continue;
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SlotIndex Def = VNI->def;
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LR.addSegment(LiveRange::Segment(Def, Def.getDeadSlot(), VNI));
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}
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}
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void LiveIntervals::extendSegmentsToUses(LiveRange &Segments,
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ShrinkToUsesWorkList &WorkList,
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Register Reg, LaneBitmask LaneMask) {
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// Keep track of the PHIs that are in use.
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SmallPtrSet<VNInfo*, 8> UsedPHIs;
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// Blocks that have already been added to WorkList as live-out.
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SmallPtrSet<const MachineBasicBlock*, 16> LiveOut;
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auto getSubRange = [](const LiveInterval &I, LaneBitmask M)
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-> const LiveRange& {
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if (M.none())
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return I;
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for (const LiveInterval::SubRange &SR : I.subranges()) {
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if ((SR.LaneMask & M).any()) {
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assert(SR.LaneMask == M && "Expecting lane masks to match exactly");
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return SR;
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}
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}
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llvm_unreachable("Subrange for mask not found");
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};
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const LiveInterval &LI = getInterval(Reg);
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const LiveRange &OldRange = getSubRange(LI, LaneMask);
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// Extend intervals to reach all uses in WorkList.
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while (!WorkList.empty()) {
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SlotIndex Idx = WorkList.back().first;
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VNInfo *VNI = WorkList.back().second;
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WorkList.pop_back();
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const MachineBasicBlock *MBB = Indexes->getMBBFromIndex(Idx.getPrevSlot());
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SlotIndex BlockStart = Indexes->getMBBStartIdx(MBB);
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// Extend the live range for VNI to be live at Idx.
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if (VNInfo *ExtVNI = Segments.extendInBlock(BlockStart, Idx)) {
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assert(ExtVNI == VNI && "Unexpected existing value number");
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(void)ExtVNI;
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// Is this a PHIDef we haven't seen before?
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if (!VNI->isPHIDef() || VNI->def != BlockStart ||
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!UsedPHIs.insert(VNI).second)
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continue;
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// The PHI is live, make sure the predecessors are live-out.
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for (const MachineBasicBlock *Pred : MBB->predecessors()) {
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if (!LiveOut.insert(Pred).second)
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continue;
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SlotIndex Stop = Indexes->getMBBEndIdx(Pred);
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// A predecessor is not required to have a live-out value for a PHI.
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if (VNInfo *PVNI = OldRange.getVNInfoBefore(Stop))
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WorkList.push_back(std::make_pair(Stop, PVNI));
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}
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continue;
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}
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// VNI is live-in to MBB.
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LLVM_DEBUG(dbgs() << " live-in at " << BlockStart << '\n');
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Segments.addSegment(LiveRange::Segment(BlockStart, Idx, VNI));
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// Make sure VNI is live-out from the predecessors.
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for (const MachineBasicBlock *Pred : MBB->predecessors()) {
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if (!LiveOut.insert(Pred).second)
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continue;
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SlotIndex Stop = Indexes->getMBBEndIdx(Pred);
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if (VNInfo *OldVNI = OldRange.getVNInfoBefore(Stop)) {
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assert(OldVNI == VNI && "Wrong value out of predecessor");
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(void)OldVNI;
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WorkList.push_back(std::make_pair(Stop, VNI));
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} else {
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#ifndef NDEBUG
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// There was no old VNI. Verify that Stop is jointly dominated
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// by <undef>s for this live range.
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assert(LaneMask.any() &&
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"Missing value out of predecessor for main range");
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SmallVector<SlotIndex,8> Undefs;
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LI.computeSubRangeUndefs(Undefs, LaneMask, *MRI, *Indexes);
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assert(LiveRangeCalc::isJointlyDominated(Pred, Undefs, *Indexes) &&
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"Missing value out of predecessor for subrange");
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#endif
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}
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}
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}
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}
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bool LiveIntervals::shrinkToUses(LiveInterval *li,
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SmallVectorImpl<MachineInstr*> *dead) {
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LLVM_DEBUG(dbgs() << "Shrink: " << *li << '\n');
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assert(Register::isVirtualRegister(li->reg()) &&
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"Can only shrink virtual registers");
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|
// Shrink subregister live ranges.
|
|
bool NeedsCleanup = false;
|
|
for (LiveInterval::SubRange &S : li->subranges()) {
|
|
shrinkToUses(S, li->reg());
|
|
if (S.empty())
|
|
NeedsCleanup = true;
|
|
}
|
|
if (NeedsCleanup)
|
|
li->removeEmptySubRanges();
|
|
|
|
// Find all the values used, including PHI kills.
|
|
ShrinkToUsesWorkList WorkList;
|
|
|
|
// Visit all instructions reading li->reg().
|
|
Register Reg = li->reg();
|
|
for (MachineInstr &UseMI : MRI->reg_instructions(Reg)) {
|
|
if (UseMI.isDebugValue() || !UseMI.readsVirtualRegister(Reg))
|
|
continue;
|
|
SlotIndex Idx = getInstructionIndex(UseMI).getRegSlot();
|
|
LiveQueryResult LRQ = li->Query(Idx);
|
|
VNInfo *VNI = LRQ.valueIn();
|
|
if (!VNI) {
|
|
// This shouldn't happen: readsVirtualRegister returns true, but there is
|
|
// no live value. It is likely caused by a target getting <undef> flags
|
|
// wrong.
|
|
LLVM_DEBUG(
|
|
dbgs() << Idx << '\t' << UseMI
|
|
<< "Warning: Instr claims to read non-existent value in "
|
|
<< *li << '\n');
|
|
continue;
|
|
}
|
|
// Special case: An early-clobber tied operand reads and writes the
|
|
// register one slot early.
|
|
if (VNInfo *DefVNI = LRQ.valueDefined())
|
|
Idx = DefVNI->def;
|
|
|
|
WorkList.push_back(std::make_pair(Idx, VNI));
|
|
}
|
|
|
|
// Create new live ranges with only minimal live segments per def.
|
|
LiveRange NewLR;
|
|
createSegmentsForValues(NewLR, make_range(li->vni_begin(), li->vni_end()));
|
|
extendSegmentsToUses(NewLR, WorkList, Reg, LaneBitmask::getNone());
|
|
|
|
// Move the trimmed segments back.
|
|
li->segments.swap(NewLR.segments);
|
|
|
|
// Handle dead values.
|
|
bool CanSeparate = computeDeadValues(*li, dead);
|
|
LLVM_DEBUG(dbgs() << "Shrunk: " << *li << '\n');
|
|
return CanSeparate;
|
|
}
|
|
|
|
bool LiveIntervals::computeDeadValues(LiveInterval &LI,
|
|
SmallVectorImpl<MachineInstr*> *dead) {
|
|
bool MayHaveSplitComponents = false;
|
|
bool HaveDeadDef = false;
|
|
|
|
for (VNInfo *VNI : LI.valnos) {
|
|
if (VNI->isUnused())
|
|
continue;
|
|
SlotIndex Def = VNI->def;
|
|
LiveRange::iterator I = LI.FindSegmentContaining(Def);
|
|
assert(I != LI.end() && "Missing segment for VNI");
|
|
|
|
// Is the register live before? Otherwise we may have to add a read-undef
|
|
// flag for subregister defs.
|
|
Register VReg = LI.reg();
|
|
if (MRI->shouldTrackSubRegLiveness(VReg)) {
|
|
if ((I == LI.begin() || std::prev(I)->end < Def) && !VNI->isPHIDef()) {
|
|
MachineInstr *MI = getInstructionFromIndex(Def);
|
|
MI->setRegisterDefReadUndef(VReg);
|
|
}
|
|
}
|
|
|
|
if (I->end != Def.getDeadSlot())
|
|
continue;
|
|
if (VNI->isPHIDef()) {
|
|
// This is a dead PHI. Remove it.
|
|
VNI->markUnused();
|
|
LI.removeSegment(I);
|
|
LLVM_DEBUG(dbgs() << "Dead PHI at " << Def << " may separate interval\n");
|
|
MayHaveSplitComponents = true;
|
|
} else {
|
|
// This is a dead def. Make sure the instruction knows.
|
|
MachineInstr *MI = getInstructionFromIndex(Def);
|
|
assert(MI && "No instruction defining live value");
|
|
MI->addRegisterDead(LI.reg(), TRI);
|
|
if (HaveDeadDef)
|
|
MayHaveSplitComponents = true;
|
|
HaveDeadDef = true;
|
|
|
|
if (dead && MI->allDefsAreDead()) {
|
|
LLVM_DEBUG(dbgs() << "All defs dead: " << Def << '\t' << *MI);
|
|
dead->push_back(MI);
|
|
}
|
|
}
|
|
}
|
|
return MayHaveSplitComponents;
|
|
}
|
|
|
|
void LiveIntervals::shrinkToUses(LiveInterval::SubRange &SR, Register Reg) {
|
|
LLVM_DEBUG(dbgs() << "Shrink: " << SR << '\n');
|
|
assert(Register::isVirtualRegister(Reg) &&
|
|
"Can only shrink virtual registers");
|
|
// Find all the values used, including PHI kills.
|
|
ShrinkToUsesWorkList WorkList;
|
|
|
|
// Visit all instructions reading Reg.
|
|
SlotIndex LastIdx;
|
|
for (MachineOperand &MO : MRI->use_nodbg_operands(Reg)) {
|
|
// Skip "undef" uses.
|
|
if (!MO.readsReg())
|
|
continue;
|
|
// Maybe the operand is for a subregister we don't care about.
|
|
unsigned SubReg = MO.getSubReg();
|
|
if (SubReg != 0) {
|
|
LaneBitmask LaneMask = TRI->getSubRegIndexLaneMask(SubReg);
|
|
if ((LaneMask & SR.LaneMask).none())
|
|
continue;
|
|
}
|
|
// We only need to visit each instruction once.
|
|
MachineInstr *UseMI = MO.getParent();
|
|
SlotIndex Idx = getInstructionIndex(*UseMI).getRegSlot();
|
|
if (Idx == LastIdx)
|
|
continue;
|
|
LastIdx = Idx;
|
|
|
|
LiveQueryResult LRQ = SR.Query(Idx);
|
|
VNInfo *VNI = LRQ.valueIn();
|
|
// For Subranges it is possible that only undef values are left in that
|
|
// part of the subregister, so there is no real liverange at the use
|
|
if (!VNI)
|
|
continue;
|
|
|
|
// Special case: An early-clobber tied operand reads and writes the
|
|
// register one slot early.
|
|
if (VNInfo *DefVNI = LRQ.valueDefined())
|
|
Idx = DefVNI->def;
|
|
|
|
WorkList.push_back(std::make_pair(Idx, VNI));
|
|
}
|
|
|
|
// Create a new live ranges with only minimal live segments per def.
|
|
LiveRange NewLR;
|
|
createSegmentsForValues(NewLR, make_range(SR.vni_begin(), SR.vni_end()));
|
|
extendSegmentsToUses(NewLR, WorkList, Reg, SR.LaneMask);
|
|
|
|
// Move the trimmed ranges back.
|
|
SR.segments.swap(NewLR.segments);
|
|
|
|
// Remove dead PHI value numbers
|
|
for (VNInfo *VNI : SR.valnos) {
|
|
if (VNI->isUnused())
|
|
continue;
|
|
const LiveRange::Segment *Segment = SR.getSegmentContaining(VNI->def);
|
|
assert(Segment != nullptr && "Missing segment for VNI");
|
|
if (Segment->end != VNI->def.getDeadSlot())
|
|
continue;
|
|
if (VNI->isPHIDef()) {
|
|
// This is a dead PHI. Remove it.
|
|
LLVM_DEBUG(dbgs() << "Dead PHI at " << VNI->def
|
|
<< " may separate interval\n");
|
|
VNI->markUnused();
|
|
SR.removeSegment(*Segment);
|
|
}
|
|
}
|
|
|
|
LLVM_DEBUG(dbgs() << "Shrunk: " << SR << '\n');
|
|
}
|
|
|
|
void LiveIntervals::extendToIndices(LiveRange &LR,
|
|
ArrayRef<SlotIndex> Indices,
|
|
ArrayRef<SlotIndex> Undefs) {
|
|
assert(LICalc && "LICalc not initialized.");
|
|
LICalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator());
|
|
for (SlotIndex Idx : Indices)
|
|
LICalc->extend(LR, Idx, /*PhysReg=*/0, Undefs);
|
|
}
|
|
|
|
void LiveIntervals::pruneValue(LiveRange &LR, SlotIndex Kill,
|
|
SmallVectorImpl<SlotIndex> *EndPoints) {
|
|
LiveQueryResult LRQ = LR.Query(Kill);
|
|
VNInfo *VNI = LRQ.valueOutOrDead();
|
|
if (!VNI)
|
|
return;
|
|
|
|
MachineBasicBlock *KillMBB = Indexes->getMBBFromIndex(Kill);
|
|
SlotIndex MBBEnd = Indexes->getMBBEndIdx(KillMBB);
|
|
|
|
// If VNI isn't live out from KillMBB, the value is trivially pruned.
|
|
if (LRQ.endPoint() < MBBEnd) {
|
|
LR.removeSegment(Kill, LRQ.endPoint());
|
|
if (EndPoints) EndPoints->push_back(LRQ.endPoint());
|
|
return;
|
|
}
|
|
|
|
// VNI is live out of KillMBB.
|
|
LR.removeSegment(Kill, MBBEnd);
|
|
if (EndPoints) EndPoints->push_back(MBBEnd);
|
|
|
|
// Find all blocks that are reachable from KillMBB without leaving VNI's live
|
|
// range. It is possible that KillMBB itself is reachable, so start a DFS
|
|
// from each successor.
|
|
using VisitedTy = df_iterator_default_set<MachineBasicBlock*,9>;
|
|
VisitedTy Visited;
|
|
for (MachineBasicBlock *Succ : KillMBB->successors()) {
|
|
for (df_ext_iterator<MachineBasicBlock*, VisitedTy>
|
|
I = df_ext_begin(Succ, Visited), E = df_ext_end(Succ, Visited);
|
|
I != E;) {
|
|
MachineBasicBlock *MBB = *I;
|
|
|
|
// Check if VNI is live in to MBB.
|
|
SlotIndex MBBStart, MBBEnd;
|
|
std::tie(MBBStart, MBBEnd) = Indexes->getMBBRange(MBB);
|
|
LiveQueryResult LRQ = LR.Query(MBBStart);
|
|
if (LRQ.valueIn() != VNI) {
|
|
// This block isn't part of the VNI segment. Prune the search.
|
|
I.skipChildren();
|
|
continue;
|
|
}
|
|
|
|
// Prune the search if VNI is killed in MBB.
|
|
if (LRQ.endPoint() < MBBEnd) {
|
|
LR.removeSegment(MBBStart, LRQ.endPoint());
|
|
if (EndPoints) EndPoints->push_back(LRQ.endPoint());
|
|
I.skipChildren();
|
|
continue;
|
|
}
|
|
|
|
// VNI is live through MBB.
|
|
LR.removeSegment(MBBStart, MBBEnd);
|
|
if (EndPoints) EndPoints->push_back(MBBEnd);
|
|
++I;
|
|
}
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Register allocator hooks.
|
|
//
|
|
|
|
void LiveIntervals::addKillFlags(const VirtRegMap *VRM) {
|
|
// Keep track of regunit ranges.
|
|
SmallVector<std::pair<const LiveRange*, LiveRange::const_iterator>, 8> RU;
|
|
// Keep track of subregister ranges.
|
|
SmallVector<std::pair<const LiveInterval::SubRange*,
|
|
LiveRange::const_iterator>, 4> SRs;
|
|
|
|
for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
|
|
Register Reg = Register::index2VirtReg(i);
|
|
if (MRI->reg_nodbg_empty(Reg))
|
|
continue;
|
|
const LiveInterval &LI = getInterval(Reg);
|
|
if (LI.empty())
|
|
continue;
|
|
|
|
// Find the regunit intervals for the assigned register. They may overlap
|
|
// the virtual register live range, cancelling any kills.
|
|
RU.clear();
|
|
for (MCRegUnitIterator Unit(VRM->getPhys(Reg), TRI); Unit.isValid();
|
|
++Unit) {
|
|
const LiveRange &RURange = getRegUnit(*Unit);
|
|
if (RURange.empty())
|
|
continue;
|
|
RU.push_back(std::make_pair(&RURange, RURange.find(LI.begin()->end)));
|
|
}
|
|
|
|
if (MRI->subRegLivenessEnabled()) {
|
|
SRs.clear();
|
|
for (const LiveInterval::SubRange &SR : LI.subranges()) {
|
|
SRs.push_back(std::make_pair(&SR, SR.find(LI.begin()->end)));
|
|
}
|
|
}
|
|
|
|
// Every instruction that kills Reg corresponds to a segment range end
|
|
// point.
|
|
for (LiveInterval::const_iterator RI = LI.begin(), RE = LI.end(); RI != RE;
|
|
++RI) {
|
|
// A block index indicates an MBB edge.
|
|
if (RI->end.isBlock())
|
|
continue;
|
|
MachineInstr *MI = getInstructionFromIndex(RI->end);
|
|
if (!MI)
|
|
continue;
|
|
|
|
// Check if any of the regunits are live beyond the end of RI. That could
|
|
// happen when a physreg is defined as a copy of a virtreg:
|
|
//
|
|
// %eax = COPY %5
|
|
// FOO %5 <--- MI, cancel kill because %eax is live.
|
|
// BAR killed %eax
|
|
//
|
|
// There should be no kill flag on FOO when %5 is rewritten as %eax.
|
|
for (auto &RUP : RU) {
|
|
const LiveRange &RURange = *RUP.first;
|
|
LiveRange::const_iterator &I = RUP.second;
|
|
if (I == RURange.end())
|
|
continue;
|
|
I = RURange.advanceTo(I, RI->end);
|
|
if (I == RURange.end() || I->start >= RI->end)
|
|
continue;
|
|
// I is overlapping RI.
|
|
goto CancelKill;
|
|
}
|
|
|
|
if (MRI->subRegLivenessEnabled()) {
|
|
// When reading a partial undefined value we must not add a kill flag.
|
|
// The regalloc might have used the undef lane for something else.
|
|
// Example:
|
|
// %1 = ... ; R32: %1
|
|
// %2:high16 = ... ; R64: %2
|
|
// = read killed %2 ; R64: %2
|
|
// = read %1 ; R32: %1
|
|
// The <kill> flag is correct for %2, but the register allocator may
|
|
// assign R0L to %1, and R0 to %2 because the low 32bits of R0
|
|
// are actually never written by %2. After assignment the <kill>
|
|
// flag at the read instruction is invalid.
|
|
LaneBitmask DefinedLanesMask;
|
|
if (!SRs.empty()) {
|
|
// Compute a mask of lanes that are defined.
|
|
DefinedLanesMask = LaneBitmask::getNone();
|
|
for (auto &SRP : SRs) {
|
|
const LiveInterval::SubRange &SR = *SRP.first;
|
|
LiveRange::const_iterator &I = SRP.second;
|
|
if (I == SR.end())
|
|
continue;
|
|
I = SR.advanceTo(I, RI->end);
|
|
if (I == SR.end() || I->start >= RI->end)
|
|
continue;
|
|
// I is overlapping RI
|
|
DefinedLanesMask |= SR.LaneMask;
|
|
}
|
|
} else
|
|
DefinedLanesMask = LaneBitmask::getAll();
|
|
|
|
bool IsFullWrite = false;
|
|
for (const MachineOperand &MO : MI->operands()) {
|
|
if (!MO.isReg() || MO.getReg() != Reg)
|
|
continue;
|
|
if (MO.isUse()) {
|
|
// Reading any undefined lanes?
|
|
LaneBitmask UseMask = TRI->getSubRegIndexLaneMask(MO.getSubReg());
|
|
if ((UseMask & ~DefinedLanesMask).any())
|
|
goto CancelKill;
|
|
} else if (MO.getSubReg() == 0) {
|
|
// Writing to the full register?
|
|
assert(MO.isDef());
|
|
IsFullWrite = true;
|
|
}
|
|
}
|
|
|
|
// If an instruction writes to a subregister, a new segment starts in
|
|
// the LiveInterval. But as this is only overriding part of the register
|
|
// adding kill-flags is not correct here after registers have been
|
|
// assigned.
|
|
if (!IsFullWrite) {
|
|
// Next segment has to be adjacent in the subregister write case.
|
|
LiveRange::const_iterator N = std::next(RI);
|
|
if (N != LI.end() && N->start == RI->end)
|
|
goto CancelKill;
|
|
}
|
|
}
|
|
|
|
MI->addRegisterKilled(Reg, nullptr);
|
|
continue;
|
|
CancelKill:
|
|
MI->clearRegisterKills(Reg, nullptr);
|
|
}
|
|
}
|
|
}
|
|
|
|
MachineBasicBlock*
|
|
LiveIntervals::intervalIsInOneMBB(const LiveInterval &LI) const {
|
|
// A local live range must be fully contained inside the block, meaning it is
|
|
// defined and killed at instructions, not at block boundaries. It is not
|
|
// live in or out of any block.
|
|
//
|
|
// It is technically possible to have a PHI-defined live range identical to a
|
|
// single block, but we are going to return false in that case.
|
|
|
|
SlotIndex Start = LI.beginIndex();
|
|
if (Start.isBlock())
|
|
return nullptr;
|
|
|
|
SlotIndex Stop = LI.endIndex();
|
|
if (Stop.isBlock())
|
|
return nullptr;
|
|
|
|
// getMBBFromIndex doesn't need to search the MBB table when both indexes
|
|
// belong to proper instructions.
|
|
MachineBasicBlock *MBB1 = Indexes->getMBBFromIndex(Start);
|
|
MachineBasicBlock *MBB2 = Indexes->getMBBFromIndex(Stop);
|
|
return MBB1 == MBB2 ? MBB1 : nullptr;
|
|
}
|
|
|
|
bool
|
|
LiveIntervals::hasPHIKill(const LiveInterval &LI, const VNInfo *VNI) const {
|
|
for (const VNInfo *PHI : LI.valnos) {
|
|
if (PHI->isUnused() || !PHI->isPHIDef())
|
|
continue;
|
|
const MachineBasicBlock *PHIMBB = getMBBFromIndex(PHI->def);
|
|
// Conservatively return true instead of scanning huge predecessor lists.
|
|
if (PHIMBB->pred_size() > 100)
|
|
return true;
|
|
for (const MachineBasicBlock *Pred : PHIMBB->predecessors())
|
|
if (VNI == LI.getVNInfoBefore(Indexes->getMBBEndIdx(Pred)))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
float LiveIntervals::getSpillWeight(bool isDef, bool isUse,
|
|
const MachineBlockFrequencyInfo *MBFI,
|
|
const MachineInstr &MI) {
|
|
return getSpillWeight(isDef, isUse, MBFI, MI.getParent());
|
|
}
|
|
|
|
float LiveIntervals::getSpillWeight(bool isDef, bool isUse,
|
|
const MachineBlockFrequencyInfo *MBFI,
|
|
const MachineBasicBlock *MBB) {
|
|
return (isDef + isUse) * MBFI->getBlockFreqRelativeToEntryBlock(MBB);
|
|
}
|
|
|
|
LiveRange::Segment
|
|
LiveIntervals::addSegmentToEndOfBlock(Register Reg, MachineInstr &startInst) {
|
|
LiveInterval &Interval = createEmptyInterval(Reg);
|
|
VNInfo *VN = Interval.getNextValue(
|
|
SlotIndex(getInstructionIndex(startInst).getRegSlot()),
|
|
getVNInfoAllocator());
|
|
LiveRange::Segment S(SlotIndex(getInstructionIndex(startInst).getRegSlot()),
|
|
getMBBEndIdx(startInst.getParent()), VN);
|
|
Interval.addSegment(S);
|
|
|
|
return S;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Register mask functions
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
bool LiveIntervals::checkRegMaskInterference(LiveInterval &LI,
|
|
BitVector &UsableRegs) {
|
|
if (LI.empty())
|
|
return false;
|
|
LiveInterval::iterator LiveI = LI.begin(), LiveE = LI.end();
|
|
|
|
// Use a smaller arrays for local live ranges.
|
|
ArrayRef<SlotIndex> Slots;
|
|
ArrayRef<const uint32_t*> Bits;
|
|
if (MachineBasicBlock *MBB = intervalIsInOneMBB(LI)) {
|
|
Slots = getRegMaskSlotsInBlock(MBB->getNumber());
|
|
Bits = getRegMaskBitsInBlock(MBB->getNumber());
|
|
} else {
|
|
Slots = getRegMaskSlots();
|
|
Bits = getRegMaskBits();
|
|
}
|
|
|
|
// We are going to enumerate all the register mask slots contained in LI.
|
|
// Start with a binary search of RegMaskSlots to find a starting point.
|
|
ArrayRef<SlotIndex>::iterator SlotI = llvm::lower_bound(Slots, LiveI->start);
|
|
ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
|
|
|
|
// No slots in range, LI begins after the last call.
|
|
if (SlotI == SlotE)
|
|
return false;
|
|
|
|
bool Found = false;
|
|
while (true) {
|
|
assert(*SlotI >= LiveI->start);
|
|
// Loop over all slots overlapping this segment.
|
|
while (*SlotI < LiveI->end) {
|
|
// *SlotI overlaps LI. Collect mask bits.
|
|
if (!Found) {
|
|
// This is the first overlap. Initialize UsableRegs to all ones.
|
|
UsableRegs.clear();
|
|
UsableRegs.resize(TRI->getNumRegs(), true);
|
|
Found = true;
|
|
}
|
|
// Remove usable registers clobbered by this mask.
|
|
UsableRegs.clearBitsNotInMask(Bits[SlotI-Slots.begin()]);
|
|
if (++SlotI == SlotE)
|
|
return Found;
|
|
}
|
|
// *SlotI is beyond the current LI segment.
|
|
LiveI = LI.advanceTo(LiveI, *SlotI);
|
|
if (LiveI == LiveE)
|
|
return Found;
|
|
// Advance SlotI until it overlaps.
|
|
while (*SlotI < LiveI->start)
|
|
if (++SlotI == SlotE)
|
|
return Found;
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// IntervalUpdate class.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
/// Toolkit used by handleMove to trim or extend live intervals.
|
|
class LiveIntervals::HMEditor {
|
|
private:
|
|
LiveIntervals& LIS;
|
|
const MachineRegisterInfo& MRI;
|
|
const TargetRegisterInfo& TRI;
|
|
SlotIndex OldIdx;
|
|
SlotIndex NewIdx;
|
|
SmallPtrSet<LiveRange*, 8> Updated;
|
|
bool UpdateFlags;
|
|
|
|
public:
|
|
HMEditor(LiveIntervals& LIS, const MachineRegisterInfo& MRI,
|
|
const TargetRegisterInfo& TRI,
|
|
SlotIndex OldIdx, SlotIndex NewIdx, bool UpdateFlags)
|
|
: LIS(LIS), MRI(MRI), TRI(TRI), OldIdx(OldIdx), NewIdx(NewIdx),
|
|
UpdateFlags(UpdateFlags) {}
|
|
|
|
// FIXME: UpdateFlags is a workaround that creates live intervals for all
|
|
// physregs, even those that aren't needed for regalloc, in order to update
|
|
// kill flags. This is wasteful. Eventually, LiveVariables will strip all kill
|
|
// flags, and postRA passes will use a live register utility instead.
|
|
LiveRange *getRegUnitLI(unsigned Unit) {
|
|
if (UpdateFlags && !MRI.isReservedRegUnit(Unit))
|
|
return &LIS.getRegUnit(Unit);
|
|
return LIS.getCachedRegUnit(Unit);
|
|
}
|
|
|
|
/// Update all live ranges touched by MI, assuming a move from OldIdx to
|
|
/// NewIdx.
|
|
void updateAllRanges(MachineInstr *MI) {
|
|
LLVM_DEBUG(dbgs() << "handleMove " << OldIdx << " -> " << NewIdx << ": "
|
|
<< *MI);
|
|
bool hasRegMask = false;
|
|
for (MachineOperand &MO : MI->operands()) {
|
|
if (MO.isRegMask())
|
|
hasRegMask = true;
|
|
if (!MO.isReg())
|
|
continue;
|
|
if (MO.isUse()) {
|
|
if (!MO.readsReg())
|
|
continue;
|
|
// Aggressively clear all kill flags.
|
|
// They are reinserted by VirtRegRewriter.
|
|
MO.setIsKill(false);
|
|
}
|
|
|
|
Register Reg = MO.getReg();
|
|
if (!Reg)
|
|
continue;
|
|
if (Register::isVirtualRegister(Reg)) {
|
|
LiveInterval &LI = LIS.getInterval(Reg);
|
|
if (LI.hasSubRanges()) {
|
|
unsigned SubReg = MO.getSubReg();
|
|
LaneBitmask LaneMask = SubReg ? TRI.getSubRegIndexLaneMask(SubReg)
|
|
: MRI.getMaxLaneMaskForVReg(Reg);
|
|
for (LiveInterval::SubRange &S : LI.subranges()) {
|
|
if ((S.LaneMask & LaneMask).none())
|
|
continue;
|
|
updateRange(S, Reg, S.LaneMask);
|
|
}
|
|
}
|
|
updateRange(LI, Reg, LaneBitmask::getNone());
|
|
// If main range has a hole and we are moving a subrange use across
|
|
// the hole updateRange() cannot properly handle it since it only
|
|
// gets the LiveRange and not the whole LiveInterval. As a result
|
|
// we may end up with a main range not covering all subranges.
|
|
// This is extremely rare case, so let's check and reconstruct the
|
|
// main range.
|
|
for (LiveInterval::SubRange &S : LI.subranges()) {
|
|
if (LI.covers(S))
|
|
continue;
|
|
LI.clear();
|
|
LIS.constructMainRangeFromSubranges(LI);
|
|
break;
|
|
}
|
|
|
|
continue;
|
|
}
|
|
|
|
// For physregs, only update the regunits that actually have a
|
|
// precomputed live range.
|
|
for (MCRegUnitIterator Units(Reg.asMCReg(), &TRI); Units.isValid();
|
|
++Units)
|
|
if (LiveRange *LR = getRegUnitLI(*Units))
|
|
updateRange(*LR, *Units, LaneBitmask::getNone());
|
|
}
|
|
if (hasRegMask)
|
|
updateRegMaskSlots();
|
|
}
|
|
|
|
private:
|
|
/// Update a single live range, assuming an instruction has been moved from
|
|
/// OldIdx to NewIdx.
|
|
void updateRange(LiveRange &LR, Register Reg, LaneBitmask LaneMask) {
|
|
if (!Updated.insert(&LR).second)
|
|
return;
|
|
LLVM_DEBUG({
|
|
dbgs() << " ";
|
|
if (Register::isVirtualRegister(Reg)) {
|
|
dbgs() << printReg(Reg);
|
|
if (LaneMask.any())
|
|
dbgs() << " L" << PrintLaneMask(LaneMask);
|
|
} else {
|
|
dbgs() << printRegUnit(Reg, &TRI);
|
|
}
|
|
dbgs() << ":\t" << LR << '\n';
|
|
});
|
|
if (SlotIndex::isEarlierInstr(OldIdx, NewIdx))
|
|
handleMoveDown(LR);
|
|
else
|
|
handleMoveUp(LR, Reg, LaneMask);
|
|
LLVM_DEBUG(dbgs() << " -->\t" << LR << '\n');
|
|
LR.verify();
|
|
}
|
|
|
|
/// Update LR to reflect an instruction has been moved downwards from OldIdx
|
|
/// to NewIdx (OldIdx < NewIdx).
|
|
void handleMoveDown(LiveRange &LR) {
|
|
LiveRange::iterator E = LR.end();
|
|
// Segment going into OldIdx.
|
|
LiveRange::iterator OldIdxIn = LR.find(OldIdx.getBaseIndex());
|
|
|
|
// No value live before or after OldIdx? Nothing to do.
|
|
if (OldIdxIn == E || SlotIndex::isEarlierInstr(OldIdx, OldIdxIn->start))
|
|
return;
|
|
|
|
LiveRange::iterator OldIdxOut;
|
|
// Do we have a value live-in to OldIdx?
|
|
if (SlotIndex::isEarlierInstr(OldIdxIn->start, OldIdx)) {
|
|
// If the live-in value already extends to NewIdx, there is nothing to do.
|
|
if (SlotIndex::isEarlierEqualInstr(NewIdx, OldIdxIn->end))
|
|
return;
|
|
// Aggressively remove all kill flags from the old kill point.
|
|
// Kill flags shouldn't be used while live intervals exist, they will be
|
|
// reinserted by VirtRegRewriter.
|
|
if (MachineInstr *KillMI = LIS.getInstructionFromIndex(OldIdxIn->end))
|
|
for (MachineOperand &MOP : mi_bundle_ops(*KillMI))
|
|
if (MOP.isReg() && MOP.isUse())
|
|
MOP.setIsKill(false);
|
|
|
|
// Is there a def before NewIdx which is not OldIdx?
|
|
LiveRange::iterator Next = std::next(OldIdxIn);
|
|
if (Next != E && !SlotIndex::isSameInstr(OldIdx, Next->start) &&
|
|
SlotIndex::isEarlierInstr(Next->start, NewIdx)) {
|
|
// If we are here then OldIdx was just a use but not a def. We only have
|
|
// to ensure liveness extends to NewIdx.
|
|
LiveRange::iterator NewIdxIn =
|
|
LR.advanceTo(Next, NewIdx.getBaseIndex());
|
|
// Extend the segment before NewIdx if necessary.
|
|
if (NewIdxIn == E ||
|
|
!SlotIndex::isEarlierInstr(NewIdxIn->start, NewIdx)) {
|
|
LiveRange::iterator Prev = std::prev(NewIdxIn);
|
|
Prev->end = NewIdx.getRegSlot();
|
|
}
|
|
// Extend OldIdxIn.
|
|
OldIdxIn->end = Next->start;
|
|
return;
|
|
}
|
|
|
|
// Adjust OldIdxIn->end to reach NewIdx. This may temporarily make LR
|
|
// invalid by overlapping ranges.
|
|
bool isKill = SlotIndex::isSameInstr(OldIdx, OldIdxIn->end);
|
|
OldIdxIn->end = NewIdx.getRegSlot(OldIdxIn->end.isEarlyClobber());
|
|
// If this was not a kill, then there was no def and we're done.
|
|
if (!isKill)
|
|
return;
|
|
|
|
// Did we have a Def at OldIdx?
|
|
OldIdxOut = Next;
|
|
if (OldIdxOut == E || !SlotIndex::isSameInstr(OldIdx, OldIdxOut->start))
|
|
return;
|
|
} else {
|
|
OldIdxOut = OldIdxIn;
|
|
}
|
|
|
|
// If we are here then there is a Definition at OldIdx. OldIdxOut points
|
|
// to the segment starting there.
|
|
assert(OldIdxOut != E && SlotIndex::isSameInstr(OldIdx, OldIdxOut->start) &&
|
|
"No def?");
|
|
VNInfo *OldIdxVNI = OldIdxOut->valno;
|
|
assert(OldIdxVNI->def == OldIdxOut->start && "Inconsistent def");
|
|
|
|
// If the defined value extends beyond NewIdx, just move the beginning
|
|
// of the segment to NewIdx.
|
|
SlotIndex NewIdxDef = NewIdx.getRegSlot(OldIdxOut->start.isEarlyClobber());
|
|
if (SlotIndex::isEarlierInstr(NewIdxDef, OldIdxOut->end)) {
|
|
OldIdxVNI->def = NewIdxDef;
|
|
OldIdxOut->start = OldIdxVNI->def;
|
|
return;
|
|
}
|
|
|
|
// If we are here then we have a Definition at OldIdx which ends before
|
|
// NewIdx.
|
|
|
|
// Is there an existing Def at NewIdx?
|
|
LiveRange::iterator AfterNewIdx
|
|
= LR.advanceTo(OldIdxOut, NewIdx.getRegSlot());
|
|
bool OldIdxDefIsDead = OldIdxOut->end.isDead();
|
|
if (!OldIdxDefIsDead &&
|
|
SlotIndex::isEarlierInstr(OldIdxOut->end, NewIdxDef)) {
|
|
// OldIdx is not a dead def, and NewIdxDef is inside a new interval.
|
|
VNInfo *DefVNI;
|
|
if (OldIdxOut != LR.begin() &&
|
|
!SlotIndex::isEarlierInstr(std::prev(OldIdxOut)->end,
|
|
OldIdxOut->start)) {
|
|
// There is no gap between OldIdxOut and its predecessor anymore,
|
|
// merge them.
|
|
LiveRange::iterator IPrev = std::prev(OldIdxOut);
|
|
DefVNI = OldIdxVNI;
|
|
IPrev->end = OldIdxOut->end;
|
|
} else {
|
|
// The value is live in to OldIdx
|
|
LiveRange::iterator INext = std::next(OldIdxOut);
|
|
assert(INext != E && "Must have following segment");
|
|
// We merge OldIdxOut and its successor. As we're dealing with subreg
|
|
// reordering, there is always a successor to OldIdxOut in the same BB
|
|
// We don't need INext->valno anymore and will reuse for the new segment
|
|
// we create later.
|
|
DefVNI = OldIdxVNI;
|
|
INext->start = OldIdxOut->end;
|
|
INext->valno->def = INext->start;
|
|
}
|
|
// If NewIdx is behind the last segment, extend that and append a new one.
|
|
if (AfterNewIdx == E) {
|
|
// OldIdxOut is undef at this point, Slide (OldIdxOut;AfterNewIdx] up
|
|
// one position.
|
|
// |- ?/OldIdxOut -| |- X0 -| ... |- Xn -| end
|
|
// => |- X0/OldIdxOut -| ... |- Xn -| |- undef/NewS -| end
|
|
std::copy(std::next(OldIdxOut), E, OldIdxOut);
|
|
// The last segment is undefined now, reuse it for a dead def.
|
|
LiveRange::iterator NewSegment = std::prev(E);
|
|
*NewSegment = LiveRange::Segment(NewIdxDef, NewIdxDef.getDeadSlot(),
|
|
DefVNI);
|
|
DefVNI->def = NewIdxDef;
|
|
|
|
LiveRange::iterator Prev = std::prev(NewSegment);
|
|
Prev->end = NewIdxDef;
|
|
} else {
|
|
// OldIdxOut is undef at this point, Slide (OldIdxOut;AfterNewIdx] up
|
|
// one position.
|
|
// |- ?/OldIdxOut -| |- X0 -| ... |- Xn/AfterNewIdx -| |- Next -|
|
|
// => |- X0/OldIdxOut -| ... |- Xn -| |- Xn/AfterNewIdx -| |- Next -|
|
|
std::copy(std::next(OldIdxOut), std::next(AfterNewIdx), OldIdxOut);
|
|
LiveRange::iterator Prev = std::prev(AfterNewIdx);
|
|
// We have two cases:
|
|
if (SlotIndex::isEarlierInstr(Prev->start, NewIdxDef)) {
|
|
// Case 1: NewIdx is inside a liverange. Split this liverange at
|
|
// NewIdxDef into the segment "Prev" followed by "NewSegment".
|
|
LiveRange::iterator NewSegment = AfterNewIdx;
|
|
*NewSegment = LiveRange::Segment(NewIdxDef, Prev->end, Prev->valno);
|
|
Prev->valno->def = NewIdxDef;
|
|
|
|
*Prev = LiveRange::Segment(Prev->start, NewIdxDef, DefVNI);
|
|
DefVNI->def = Prev->start;
|
|
} else {
|
|
// Case 2: NewIdx is in a lifetime hole. Keep AfterNewIdx as is and
|
|
// turn Prev into a segment from NewIdx to AfterNewIdx->start.
|
|
*Prev = LiveRange::Segment(NewIdxDef, AfterNewIdx->start, DefVNI);
|
|
DefVNI->def = NewIdxDef;
|
|
assert(DefVNI != AfterNewIdx->valno);
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (AfterNewIdx != E &&
|
|
SlotIndex::isSameInstr(AfterNewIdx->start, NewIdxDef)) {
|
|
// There is an existing def at NewIdx. The def at OldIdx is coalesced into
|
|
// that value.
|
|
assert(AfterNewIdx->valno != OldIdxVNI && "Multiple defs of value?");
|
|
LR.removeValNo(OldIdxVNI);
|
|
} else {
|
|
// There was no existing def at NewIdx. We need to create a dead def
|
|
// at NewIdx. Shift segments over the old OldIdxOut segment, this frees
|
|
// a new segment at the place where we want to construct the dead def.
|
|
// |- OldIdxOut -| |- X0 -| ... |- Xn -| |- AfterNewIdx -|
|
|
// => |- X0/OldIdxOut -| ... |- Xn -| |- undef/NewS. -| |- AfterNewIdx -|
|
|
assert(AfterNewIdx != OldIdxOut && "Inconsistent iterators");
|
|
std::copy(std::next(OldIdxOut), AfterNewIdx, OldIdxOut);
|
|
// We can reuse OldIdxVNI now.
|
|
LiveRange::iterator NewSegment = std::prev(AfterNewIdx);
|
|
VNInfo *NewSegmentVNI = OldIdxVNI;
|
|
NewSegmentVNI->def = NewIdxDef;
|
|
*NewSegment = LiveRange::Segment(NewIdxDef, NewIdxDef.getDeadSlot(),
|
|
NewSegmentVNI);
|
|
}
|
|
}
|
|
|
|
/// Update LR to reflect an instruction has been moved upwards from OldIdx
|
|
/// to NewIdx (NewIdx < OldIdx).
|
|
void handleMoveUp(LiveRange &LR, Register Reg, LaneBitmask LaneMask) {
|
|
LiveRange::iterator E = LR.end();
|
|
// Segment going into OldIdx.
|
|
LiveRange::iterator OldIdxIn = LR.find(OldIdx.getBaseIndex());
|
|
|
|
// No value live before or after OldIdx? Nothing to do.
|
|
if (OldIdxIn == E || SlotIndex::isEarlierInstr(OldIdx, OldIdxIn->start))
|
|
return;
|
|
|
|
LiveRange::iterator OldIdxOut;
|
|
// Do we have a value live-in to OldIdx?
|
|
if (SlotIndex::isEarlierInstr(OldIdxIn->start, OldIdx)) {
|
|
// If the live-in value isn't killed here, then we have no Def at
|
|
// OldIdx, moreover the value must be live at NewIdx so there is nothing
|
|
// to do.
|
|
bool isKill = SlotIndex::isSameInstr(OldIdx, OldIdxIn->end);
|
|
if (!isKill)
|
|
return;
|
|
|
|
// At this point we have to move OldIdxIn->end back to the nearest
|
|
// previous use or (dead-)def but no further than NewIdx.
|
|
SlotIndex DefBeforeOldIdx
|
|
= std::max(OldIdxIn->start.getDeadSlot(),
|
|
NewIdx.getRegSlot(OldIdxIn->end.isEarlyClobber()));
|
|
OldIdxIn->end = findLastUseBefore(DefBeforeOldIdx, Reg, LaneMask);
|
|
|
|
// Did we have a Def at OldIdx? If not we are done now.
|
|
OldIdxOut = std::next(OldIdxIn);
|
|
if (OldIdxOut == E || !SlotIndex::isSameInstr(OldIdx, OldIdxOut->start))
|
|
return;
|
|
} else {
|
|
OldIdxOut = OldIdxIn;
|
|
OldIdxIn = OldIdxOut != LR.begin() ? std::prev(OldIdxOut) : E;
|
|
}
|
|
|
|
// If we are here then there is a Definition at OldIdx. OldIdxOut points
|
|
// to the segment starting there.
|
|
assert(OldIdxOut != E && SlotIndex::isSameInstr(OldIdx, OldIdxOut->start) &&
|
|
"No def?");
|
|
VNInfo *OldIdxVNI = OldIdxOut->valno;
|
|
assert(OldIdxVNI->def == OldIdxOut->start && "Inconsistent def");
|
|
bool OldIdxDefIsDead = OldIdxOut->end.isDead();
|
|
|
|
// Is there an existing def at NewIdx?
|
|
SlotIndex NewIdxDef = NewIdx.getRegSlot(OldIdxOut->start.isEarlyClobber());
|
|
LiveRange::iterator NewIdxOut = LR.find(NewIdx.getRegSlot());
|
|
if (SlotIndex::isSameInstr(NewIdxOut->start, NewIdx)) {
|
|
assert(NewIdxOut->valno != OldIdxVNI &&
|
|
"Same value defined more than once?");
|
|
// If OldIdx was a dead def remove it.
|
|
if (!OldIdxDefIsDead) {
|
|
// Remove segment starting at NewIdx and move begin of OldIdxOut to
|
|
// NewIdx so it can take its place.
|
|
OldIdxVNI->def = NewIdxDef;
|
|
OldIdxOut->start = NewIdxDef;
|
|
LR.removeValNo(NewIdxOut->valno);
|
|
} else {
|
|
// Simply remove the dead def at OldIdx.
|
|
LR.removeValNo(OldIdxVNI);
|
|
}
|
|
} else {
|
|
// Previously nothing was live after NewIdx, so all we have to do now is
|
|
// move the begin of OldIdxOut to NewIdx.
|
|
if (!OldIdxDefIsDead) {
|
|
// Do we have any intermediate Defs between OldIdx and NewIdx?
|
|
if (OldIdxIn != E &&
|
|
SlotIndex::isEarlierInstr(NewIdxDef, OldIdxIn->start)) {
|
|
// OldIdx is not a dead def and NewIdx is before predecessor start.
|
|
LiveRange::iterator NewIdxIn = NewIdxOut;
|
|
assert(NewIdxIn == LR.find(NewIdx.getBaseIndex()));
|
|
const SlotIndex SplitPos = NewIdxDef;
|
|
OldIdxVNI = OldIdxIn->valno;
|
|
|
|
SlotIndex NewDefEndPoint = std::next(NewIdxIn)->end;
|
|
LiveRange::iterator Prev = std::prev(OldIdxIn);
|
|
if (OldIdxIn != LR.begin() &&
|
|
SlotIndex::isEarlierInstr(NewIdx, Prev->end)) {
|
|
// If the segment before OldIdx read a value defined earlier than
|
|
// NewIdx, the moved instruction also reads and forwards that
|
|
// value. Extend the lifetime of the new def point.
|
|
|
|
// Extend to where the previous range started, unless there is
|
|
// another redef first.
|
|
NewDefEndPoint = std::min(OldIdxIn->start,
|
|
std::next(NewIdxOut)->start);
|
|
}
|
|
|
|
// Merge the OldIdxIn and OldIdxOut segments into OldIdxOut.
|
|
OldIdxOut->valno->def = OldIdxIn->start;
|
|
*OldIdxOut = LiveRange::Segment(OldIdxIn->start, OldIdxOut->end,
|
|
OldIdxOut->valno);
|
|
// OldIdxIn and OldIdxVNI are now undef and can be overridden.
|
|
// We Slide [NewIdxIn, OldIdxIn) down one position.
|
|
// |- X0/NewIdxIn -| ... |- Xn-1 -||- Xn/OldIdxIn -||- OldIdxOut -|
|
|
// => |- undef/NexIdxIn -| |- X0 -| ... |- Xn-1 -| |- Xn/OldIdxOut -|
|
|
std::copy_backward(NewIdxIn, OldIdxIn, OldIdxOut);
|
|
// NewIdxIn is now considered undef so we can reuse it for the moved
|
|
// value.
|
|
LiveRange::iterator NewSegment = NewIdxIn;
|
|
LiveRange::iterator Next = std::next(NewSegment);
|
|
if (SlotIndex::isEarlierInstr(Next->start, NewIdx)) {
|
|
// There is no gap between NewSegment and its predecessor.
|
|
*NewSegment = LiveRange::Segment(Next->start, SplitPos,
|
|
Next->valno);
|
|
|
|
*Next = LiveRange::Segment(SplitPos, NewDefEndPoint, OldIdxVNI);
|
|
Next->valno->def = SplitPos;
|
|
} else {
|
|
// There is a gap between NewSegment and its predecessor
|
|
// Value becomes live in.
|
|
*NewSegment = LiveRange::Segment(SplitPos, Next->start, OldIdxVNI);
|
|
NewSegment->valno->def = SplitPos;
|
|
}
|
|
} else {
|
|
// Leave the end point of a live def.
|
|
OldIdxOut->start = NewIdxDef;
|
|
OldIdxVNI->def = NewIdxDef;
|
|
if (OldIdxIn != E && SlotIndex::isEarlierInstr(NewIdx, OldIdxIn->end))
|
|
OldIdxIn->end = NewIdxDef;
|
|
}
|
|
} else if (OldIdxIn != E
|
|
&& SlotIndex::isEarlierInstr(NewIdxOut->start, NewIdx)
|
|
&& SlotIndex::isEarlierInstr(NewIdx, NewIdxOut->end)) {
|
|
// OldIdxVNI is a dead def that has been moved into the middle of
|
|
// another value in LR. That can happen when LR is a whole register,
|
|
// but the dead def is a write to a subreg that is dead at NewIdx.
|
|
// The dead def may have been moved across other values
|
|
// in LR, so move OldIdxOut up to NewIdxOut. Slide [NewIdxOut;OldIdxOut)
|
|
// down one position.
|
|
// |- X0/NewIdxOut -| ... |- Xn-1 -| |- Xn/OldIdxOut -| |- next - |
|
|
// => |- X0/NewIdxOut -| |- X0 -| ... |- Xn-1 -| |- next -|
|
|
std::copy_backward(NewIdxOut, OldIdxOut, std::next(OldIdxOut));
|
|
// Modify the segment at NewIdxOut and the following segment to meet at
|
|
// the point of the dead def, with the following segment getting
|
|
// OldIdxVNI as its value number.
|
|
*NewIdxOut = LiveRange::Segment(
|
|
NewIdxOut->start, NewIdxDef.getRegSlot(), NewIdxOut->valno);
|
|
*(NewIdxOut + 1) = LiveRange::Segment(
|
|
NewIdxDef.getRegSlot(), (NewIdxOut + 1)->end, OldIdxVNI);
|
|
OldIdxVNI->def = NewIdxDef;
|
|
// Modify subsequent segments to be defined by the moved def OldIdxVNI.
|
|
for (auto Idx = NewIdxOut + 2; Idx <= OldIdxOut; ++Idx)
|
|
Idx->valno = OldIdxVNI;
|
|
// Aggressively remove all dead flags from the former dead definition.
|
|
// Kill/dead flags shouldn't be used while live intervals exist; they
|
|
// will be reinserted by VirtRegRewriter.
|
|
if (MachineInstr *KillMI = LIS.getInstructionFromIndex(NewIdx))
|
|
for (MIBundleOperands MO(*KillMI); MO.isValid(); ++MO)
|
|
if (MO->isReg() && !MO->isUse())
|
|
MO->setIsDead(false);
|
|
} else {
|
|
// OldIdxVNI is a dead def. It may have been moved across other values
|
|
// in LR, so move OldIdxOut up to NewIdxOut. Slide [NewIdxOut;OldIdxOut)
|
|
// down one position.
|
|
// |- X0/NewIdxOut -| ... |- Xn-1 -| |- Xn/OldIdxOut -| |- next - |
|
|
// => |- undef/NewIdxOut -| |- X0 -| ... |- Xn-1 -| |- next -|
|
|
std::copy_backward(NewIdxOut, OldIdxOut, std::next(OldIdxOut));
|
|
// OldIdxVNI can be reused now to build a new dead def segment.
|
|
LiveRange::iterator NewSegment = NewIdxOut;
|
|
VNInfo *NewSegmentVNI = OldIdxVNI;
|
|
*NewSegment = LiveRange::Segment(NewIdxDef, NewIdxDef.getDeadSlot(),
|
|
NewSegmentVNI);
|
|
NewSegmentVNI->def = NewIdxDef;
|
|
}
|
|
}
|
|
}
|
|
|
|
void updateRegMaskSlots() {
|
|
SmallVectorImpl<SlotIndex>::iterator RI =
|
|
llvm::lower_bound(LIS.RegMaskSlots, OldIdx);
|
|
assert(RI != LIS.RegMaskSlots.end() && *RI == OldIdx.getRegSlot() &&
|
|
"No RegMask at OldIdx.");
|
|
*RI = NewIdx.getRegSlot();
|
|
assert((RI == LIS.RegMaskSlots.begin() ||
|
|
SlotIndex::isEarlierInstr(*std::prev(RI), *RI)) &&
|
|
"Cannot move regmask instruction above another call");
|
|
assert((std::next(RI) == LIS.RegMaskSlots.end() ||
|
|
SlotIndex::isEarlierInstr(*RI, *std::next(RI))) &&
|
|
"Cannot move regmask instruction below another call");
|
|
}
|
|
|
|
// Return the last use of reg between NewIdx and OldIdx.
|
|
SlotIndex findLastUseBefore(SlotIndex Before, Register Reg,
|
|
LaneBitmask LaneMask) {
|
|
if (Register::isVirtualRegister(Reg)) {
|
|
SlotIndex LastUse = Before;
|
|
for (MachineOperand &MO : MRI.use_nodbg_operands(Reg)) {
|
|
if (MO.isUndef())
|
|
continue;
|
|
unsigned SubReg = MO.getSubReg();
|
|
if (SubReg != 0 && LaneMask.any()
|
|
&& (TRI.getSubRegIndexLaneMask(SubReg) & LaneMask).none())
|
|
continue;
|
|
|
|
const MachineInstr &MI = *MO.getParent();
|
|
SlotIndex InstSlot = LIS.getSlotIndexes()->getInstructionIndex(MI);
|
|
if (InstSlot > LastUse && InstSlot < OldIdx)
|
|
LastUse = InstSlot.getRegSlot();
|
|
}
|
|
return LastUse;
|
|
}
|
|
|
|
// This is a regunit interval, so scanning the use list could be very
|
|
// expensive. Scan upwards from OldIdx instead.
|
|
assert(Before < OldIdx && "Expected upwards move");
|
|
SlotIndexes *Indexes = LIS.getSlotIndexes();
|
|
MachineBasicBlock *MBB = Indexes->getMBBFromIndex(Before);
|
|
|
|
// OldIdx may not correspond to an instruction any longer, so set MII to
|
|
// point to the next instruction after OldIdx, or MBB->end().
|
|
MachineBasicBlock::iterator MII = MBB->end();
|
|
if (MachineInstr *MI = Indexes->getInstructionFromIndex(
|
|
Indexes->getNextNonNullIndex(OldIdx)))
|
|
if (MI->getParent() == MBB)
|
|
MII = MI;
|
|
|
|
MachineBasicBlock::iterator Begin = MBB->begin();
|
|
while (MII != Begin) {
|
|
if ((--MII)->isDebugInstr())
|
|
continue;
|
|
SlotIndex Idx = Indexes->getInstructionIndex(*MII);
|
|
|
|
// Stop searching when Before is reached.
|
|
if (!SlotIndex::isEarlierInstr(Before, Idx))
|
|
return Before;
|
|
|
|
// Check if MII uses Reg.
|
|
for (MIBundleOperands MO(*MII); MO.isValid(); ++MO)
|
|
if (MO->isReg() && !MO->isUndef() &&
|
|
Register::isPhysicalRegister(MO->getReg()) &&
|
|
TRI.hasRegUnit(MO->getReg(), Reg))
|
|
return Idx.getRegSlot();
|
|
}
|
|
// Didn't reach Before. It must be the first instruction in the block.
|
|
return Before;
|
|
}
|
|
};
|
|
|
|
void LiveIntervals::handleMove(MachineInstr &MI, bool UpdateFlags) {
|
|
// It is fine to move a bundle as a whole, but not an individual instruction
|
|
// inside it.
|
|
assert((!MI.isBundled() || MI.getOpcode() == TargetOpcode::BUNDLE) &&
|
|
"Cannot move instruction in bundle");
|
|
SlotIndex OldIndex = Indexes->getInstructionIndex(MI);
|
|
Indexes->removeMachineInstrFromMaps(MI);
|
|
SlotIndex NewIndex = Indexes->insertMachineInstrInMaps(MI);
|
|
assert(getMBBStartIdx(MI.getParent()) <= OldIndex &&
|
|
OldIndex < getMBBEndIdx(MI.getParent()) &&
|
|
"Cannot handle moves across basic block boundaries.");
|
|
|
|
HMEditor HME(*this, *MRI, *TRI, OldIndex, NewIndex, UpdateFlags);
|
|
HME.updateAllRanges(&MI);
|
|
}
|
|
|
|
void LiveIntervals::handleMoveIntoNewBundle(MachineInstr &BundleStart,
|
|
bool UpdateFlags) {
|
|
assert((BundleStart.getOpcode() == TargetOpcode::BUNDLE) &&
|
|
"Bundle start is not a bundle");
|
|
SmallVector<SlotIndex, 16> ToProcess;
|
|
const SlotIndex NewIndex = Indexes->insertMachineInstrInMaps(BundleStart);
|
|
auto BundleEnd = getBundleEnd(BundleStart.getIterator());
|
|
|
|
auto I = BundleStart.getIterator();
|
|
I++;
|
|
while (I != BundleEnd) {
|
|
if (!Indexes->hasIndex(*I))
|
|
continue;
|
|
SlotIndex OldIndex = Indexes->getInstructionIndex(*I, true);
|
|
ToProcess.push_back(OldIndex);
|
|
Indexes->removeMachineInstrFromMaps(*I, true);
|
|
I++;
|
|
}
|
|
for (SlotIndex OldIndex : ToProcess) {
|
|
HMEditor HME(*this, *MRI, *TRI, OldIndex, NewIndex, UpdateFlags);
|
|
HME.updateAllRanges(&BundleStart);
|
|
}
|
|
|
|
// Fix up dead defs
|
|
const SlotIndex Index = getInstructionIndex(BundleStart);
|
|
for (unsigned Idx = 0, E = BundleStart.getNumOperands(); Idx != E; ++Idx) {
|
|
MachineOperand &MO = BundleStart.getOperand(Idx);
|
|
if (!MO.isReg())
|
|
continue;
|
|
Register Reg = MO.getReg();
|
|
if (Reg.isVirtual() && hasInterval(Reg) && !MO.isUndef()) {
|
|
LiveInterval &LI = getInterval(Reg);
|
|
LiveQueryResult LRQ = LI.Query(Index);
|
|
if (LRQ.isDeadDef())
|
|
MO.setIsDead();
|
|
}
|
|
}
|
|
}
|
|
|
|
void LiveIntervals::repairOldRegInRange(const MachineBasicBlock::iterator Begin,
|
|
const MachineBasicBlock::iterator End,
|
|
const SlotIndex EndIdx, LiveRange &LR,
|
|
const Register Reg,
|
|
LaneBitmask LaneMask) {
|
|
LiveInterval::iterator LII = LR.find(EndIdx);
|
|
SlotIndex lastUseIdx;
|
|
if (LII == LR.begin()) {
|
|
// This happens when the function is called for a subregister that only
|
|
// occurs _after_ the range that is to be repaired.
|
|
return;
|
|
}
|
|
if (LII != LR.end() && LII->start < EndIdx)
|
|
lastUseIdx = LII->end;
|
|
else
|
|
--LII;
|
|
|
|
for (MachineBasicBlock::iterator I = End; I != Begin;) {
|
|
--I;
|
|
MachineInstr &MI = *I;
|
|
if (MI.isDebugInstr())
|
|
continue;
|
|
|
|
SlotIndex instrIdx = getInstructionIndex(MI);
|
|
bool isStartValid = getInstructionFromIndex(LII->start);
|
|
bool isEndValid = getInstructionFromIndex(LII->end);
|
|
|
|
// FIXME: This doesn't currently handle early-clobber or multiple removed
|
|
// defs inside of the region to repair.
|
|
for (MachineInstr::mop_iterator OI = MI.operands_begin(),
|
|
OE = MI.operands_end();
|
|
OI != OE; ++OI) {
|
|
const MachineOperand &MO = *OI;
|
|
if (!MO.isReg() || MO.getReg() != Reg)
|
|
continue;
|
|
|
|
unsigned SubReg = MO.getSubReg();
|
|
LaneBitmask Mask = TRI->getSubRegIndexLaneMask(SubReg);
|
|
if ((Mask & LaneMask).none())
|
|
continue;
|
|
|
|
if (MO.isDef()) {
|
|
if (!isStartValid) {
|
|
if (LII->end.isDead()) {
|
|
SlotIndex prevStart;
|
|
if (LII != LR.begin())
|
|
prevStart = std::prev(LII)->start;
|
|
|
|
// FIXME: This could be more efficient if there was a
|
|
// removeSegment method that returned an iterator.
|
|
LR.removeSegment(*LII, true);
|
|
if (prevStart.isValid())
|
|
LII = LR.find(prevStart);
|
|
else
|
|
LII = LR.begin();
|
|
} else {
|
|
LII->start = instrIdx.getRegSlot();
|
|
LII->valno->def = instrIdx.getRegSlot();
|
|
if (MO.getSubReg() && !MO.isUndef())
|
|
lastUseIdx = instrIdx.getRegSlot();
|
|
else
|
|
lastUseIdx = SlotIndex();
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (!lastUseIdx.isValid()) {
|
|
VNInfo *VNI = LR.getNextValue(instrIdx.getRegSlot(), VNInfoAllocator);
|
|
LiveRange::Segment S(instrIdx.getRegSlot(),
|
|
instrIdx.getDeadSlot(), VNI);
|
|
LII = LR.addSegment(S);
|
|
} else if (LII->start != instrIdx.getRegSlot()) {
|
|
VNInfo *VNI = LR.getNextValue(instrIdx.getRegSlot(), VNInfoAllocator);
|
|
LiveRange::Segment S(instrIdx.getRegSlot(), lastUseIdx, VNI);
|
|
LII = LR.addSegment(S);
|
|
}
|
|
|
|
if (MO.getSubReg() && !MO.isUndef())
|
|
lastUseIdx = instrIdx.getRegSlot();
|
|
else
|
|
lastUseIdx = SlotIndex();
|
|
} else if (MO.isUse()) {
|
|
// FIXME: This should probably be handled outside of this branch,
|
|
// either as part of the def case (for defs inside of the region) or
|
|
// after the loop over the region.
|
|
if (!isEndValid && !LII->end.isBlock())
|
|
LII->end = instrIdx.getRegSlot();
|
|
if (!lastUseIdx.isValid())
|
|
lastUseIdx = instrIdx.getRegSlot();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
LiveIntervals::repairIntervalsInRange(MachineBasicBlock *MBB,
|
|
MachineBasicBlock::iterator Begin,
|
|
MachineBasicBlock::iterator End,
|
|
ArrayRef<Register> OrigRegs) {
|
|
// Find anchor points, which are at the beginning/end of blocks or at
|
|
// instructions that already have indexes.
|
|
while (Begin != MBB->begin() && !Indexes->hasIndex(*Begin))
|
|
--Begin;
|
|
while (End != MBB->end() && !Indexes->hasIndex(*End))
|
|
++End;
|
|
|
|
SlotIndex EndIdx;
|
|
if (End == MBB->end())
|
|
EndIdx = getMBBEndIdx(MBB).getPrevSlot();
|
|
else
|
|
EndIdx = getInstructionIndex(*End);
|
|
|
|
Indexes->repairIndexesInRange(MBB, Begin, End);
|
|
|
|
for (MachineBasicBlock::iterator I = End; I != Begin;) {
|
|
--I;
|
|
MachineInstr &MI = *I;
|
|
if (MI.isDebugInstr())
|
|
continue;
|
|
for (MachineInstr::const_mop_iterator MOI = MI.operands_begin(),
|
|
MOE = MI.operands_end();
|
|
MOI != MOE; ++MOI) {
|
|
if (MOI->isReg() && Register::isVirtualRegister(MOI->getReg()) &&
|
|
!hasInterval(MOI->getReg())) {
|
|
createAndComputeVirtRegInterval(MOI->getReg());
|
|
}
|
|
}
|
|
}
|
|
|
|
for (Register Reg : OrigRegs) {
|
|
if (!Reg.isVirtual())
|
|
continue;
|
|
|
|
LiveInterval &LI = getInterval(Reg);
|
|
// FIXME: Should we support undefs that gain defs?
|
|
if (!LI.hasAtLeastOneValue())
|
|
continue;
|
|
|
|
for (LiveInterval::SubRange &S : LI.subranges())
|
|
repairOldRegInRange(Begin, End, EndIdx, S, Reg, S.LaneMask);
|
|
|
|
repairOldRegInRange(Begin, End, EndIdx, LI, Reg);
|
|
}
|
|
}
|
|
|
|
void LiveIntervals::removePhysRegDefAt(MCRegister Reg, SlotIndex Pos) {
|
|
for (MCRegUnitIterator Unit(Reg, TRI); Unit.isValid(); ++Unit) {
|
|
if (LiveRange *LR = getCachedRegUnit(*Unit))
|
|
if (VNInfo *VNI = LR->getVNInfoAt(Pos))
|
|
LR->removeValNo(VNI);
|
|
}
|
|
}
|
|
|
|
void LiveIntervals::removeVRegDefAt(LiveInterval &LI, SlotIndex Pos) {
|
|
// LI may not have the main range computed yet, but its subranges may
|
|
// be present.
|
|
VNInfo *VNI = LI.getVNInfoAt(Pos);
|
|
if (VNI != nullptr) {
|
|
assert(VNI->def.getBaseIndex() == Pos.getBaseIndex());
|
|
LI.removeValNo(VNI);
|
|
}
|
|
|
|
// Also remove the value defined in subranges.
|
|
for (LiveInterval::SubRange &S : LI.subranges()) {
|
|
if (VNInfo *SVNI = S.getVNInfoAt(Pos))
|
|
if (SVNI->def.getBaseIndex() == Pos.getBaseIndex())
|
|
S.removeValNo(SVNI);
|
|
}
|
|
LI.removeEmptySubRanges();
|
|
}
|
|
|
|
void LiveIntervals::splitSeparateComponents(LiveInterval &LI,
|
|
SmallVectorImpl<LiveInterval*> &SplitLIs) {
|
|
ConnectedVNInfoEqClasses ConEQ(*this);
|
|
unsigned NumComp = ConEQ.Classify(LI);
|
|
if (NumComp <= 1)
|
|
return;
|
|
LLVM_DEBUG(dbgs() << " Split " << NumComp << " components: " << LI << '\n');
|
|
Register Reg = LI.reg();
|
|
const TargetRegisterClass *RegClass = MRI->getRegClass(Reg);
|
|
for (unsigned I = 1; I < NumComp; ++I) {
|
|
Register NewVReg = MRI->createVirtualRegister(RegClass);
|
|
LiveInterval &NewLI = createEmptyInterval(NewVReg);
|
|
SplitLIs.push_back(&NewLI);
|
|
}
|
|
ConEQ.Distribute(LI, SplitLIs.data(), *MRI);
|
|
}
|
|
|
|
void LiveIntervals::constructMainRangeFromSubranges(LiveInterval &LI) {
|
|
assert(LICalc && "LICalc not initialized.");
|
|
LICalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator());
|
|
LICalc->constructMainRangeFromSubranges(LI);
|
|
}
|