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When a live interval is being spilled, rather than creating short, non-spillable intervals for every def / use, split the interval at BB boundaries. That is, for every BB where the live interval is defined or used, create a new interval that covers all the defs and uses in the BB. This is designed to eliminate one common problem: multiple reloads of the same value in a single basic block. Note, it does *not* decrease the number of spills since no copies are inserted so the split intervals are *connected* through spill and reloads (or rematerialization). The newly created intervals can be spilled again, in that case, since it does not span multiple basic blocks, it's spilled in the usual manner. However, it can reuse the same stack slot as the previously split interval. This is currently controlled by -split-intervals-at-bb. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44198 91177308-0d34-0410-b5e6-96231b3b80d8
1146 lines
42 KiB
C++
1146 lines
42 KiB
C++
//===-- LiveIntervalAnalysis.cpp - Live Interval Analysis -----------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// 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 uses the
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// LiveVariables pass to conservatively compute live intervals for
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// each virtual and physical register.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "liveintervals"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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#include "VirtRegMap.h"
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#include "llvm/Value.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/CodeGen/LiveVariables.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/CodeGen/SSARegMap.h"
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#include "llvm/Target/MRegisterInfo.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/STLExtras.h"
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#include <algorithm>
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#include <cmath>
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using namespace llvm;
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namespace {
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// Hidden options for help debugging.
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cl::opt<bool> DisableReMat("disable-rematerialization",
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cl::init(false), cl::Hidden);
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cl::opt<bool> SplitAtBB("split-intervals-at-bb",
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cl::init(false), cl::Hidden);
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}
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STATISTIC(numIntervals, "Number of original intervals");
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STATISTIC(numIntervalsAfter, "Number of intervals after coalescing");
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STATISTIC(numFolded , "Number of loads/stores folded into instructions");
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char LiveIntervals::ID = 0;
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namespace {
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RegisterPass<LiveIntervals> X("liveintervals", "Live Interval Analysis");
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}
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void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addPreserved<LiveVariables>();
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AU.addRequired<LiveVariables>();
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AU.addPreservedID(PHIEliminationID);
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AU.addRequiredID(PHIEliminationID);
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AU.addRequiredID(TwoAddressInstructionPassID);
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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void LiveIntervals::releaseMemory() {
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Idx2MBBMap.clear();
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mi2iMap_.clear();
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i2miMap_.clear();
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r2iMap_.clear();
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// Release VNInfo memroy regions after all VNInfo objects are dtor'd.
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VNInfoAllocator.Reset();
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for (unsigned i = 0, e = ClonedMIs.size(); i != e; ++i)
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delete ClonedMIs[i];
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}
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namespace llvm {
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inline bool operator<(unsigned V, const IdxMBBPair &IM) {
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return V < IM.first;
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}
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inline bool operator<(const IdxMBBPair &IM, unsigned V) {
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return IM.first < V;
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}
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struct Idx2MBBCompare {
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bool operator()(const IdxMBBPair &LHS, const IdxMBBPair &RHS) const {
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return LHS.first < RHS.first;
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}
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};
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}
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/// runOnMachineFunction - Register allocate the whole function
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///
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bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
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mf_ = &fn;
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tm_ = &fn.getTarget();
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mri_ = tm_->getRegisterInfo();
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tii_ = tm_->getInstrInfo();
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lv_ = &getAnalysis<LiveVariables>();
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allocatableRegs_ = mri_->getAllocatableSet(fn);
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// Number MachineInstrs and MachineBasicBlocks.
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// Initialize MBB indexes to a sentinal.
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MBB2IdxMap.resize(mf_->getNumBlockIDs(), std::make_pair(~0U,~0U));
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unsigned MIIndex = 0;
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for (MachineFunction::iterator MBB = mf_->begin(), E = mf_->end();
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MBB != E; ++MBB) {
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unsigned StartIdx = MIIndex;
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for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
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I != E; ++I) {
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bool inserted = mi2iMap_.insert(std::make_pair(I, MIIndex)).second;
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assert(inserted && "multiple MachineInstr -> index mappings");
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i2miMap_.push_back(I);
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MIIndex += InstrSlots::NUM;
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}
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// Set the MBB2IdxMap entry for this MBB.
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MBB2IdxMap[MBB->getNumber()] = std::make_pair(StartIdx, MIIndex - 1);
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Idx2MBBMap.push_back(std::make_pair(StartIdx, MBB));
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}
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std::sort(Idx2MBBMap.begin(), Idx2MBBMap.end(), Idx2MBBCompare());
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computeIntervals();
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numIntervals += getNumIntervals();
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DOUT << "********** INTERVALS **********\n";
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for (iterator I = begin(), E = end(); I != E; ++I) {
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I->second.print(DOUT, mri_);
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DOUT << "\n";
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}
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numIntervalsAfter += getNumIntervals();
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DEBUG(dump());
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return true;
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}
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/// print - Implement the dump method.
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void LiveIntervals::print(std::ostream &O, const Module* ) const {
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O << "********** INTERVALS **********\n";
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for (const_iterator I = begin(), E = end(); I != E; ++I) {
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I->second.print(DOUT, mri_);
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DOUT << "\n";
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}
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O << "********** MACHINEINSTRS **********\n";
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for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
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mbbi != mbbe; ++mbbi) {
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O << ((Value*)mbbi->getBasicBlock())->getName() << ":\n";
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for (MachineBasicBlock::iterator mii = mbbi->begin(),
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mie = mbbi->end(); mii != mie; ++mii) {
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O << getInstructionIndex(mii) << '\t' << *mii;
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}
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}
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}
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/// conflictsWithPhysRegDef - Returns true if the specified register
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/// is defined during the duration of the specified interval.
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bool LiveIntervals::conflictsWithPhysRegDef(const LiveInterval &li,
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VirtRegMap &vrm, unsigned reg) {
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for (LiveInterval::Ranges::const_iterator
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I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
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for (unsigned index = getBaseIndex(I->start),
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end = getBaseIndex(I->end-1) + InstrSlots::NUM; index != end;
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index += InstrSlots::NUM) {
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// skip deleted instructions
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while (index != end && !getInstructionFromIndex(index))
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index += InstrSlots::NUM;
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if (index == end) break;
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MachineInstr *MI = getInstructionFromIndex(index);
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unsigned SrcReg, DstReg;
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if (tii_->isMoveInstr(*MI, SrcReg, DstReg))
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if (SrcReg == li.reg || DstReg == li.reg)
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continue;
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for (unsigned i = 0; i != MI->getNumOperands(); ++i) {
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MachineOperand& mop = MI->getOperand(i);
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if (!mop.isRegister())
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continue;
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unsigned PhysReg = mop.getReg();
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if (PhysReg == 0 || PhysReg == li.reg)
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continue;
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if (MRegisterInfo::isVirtualRegister(PhysReg)) {
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if (!vrm.hasPhys(PhysReg))
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continue;
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PhysReg = vrm.getPhys(PhysReg);
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}
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if (PhysReg && mri_->regsOverlap(PhysReg, reg))
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return true;
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}
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}
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}
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return false;
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}
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void LiveIntervals::printRegName(unsigned reg) const {
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if (MRegisterInfo::isPhysicalRegister(reg))
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cerr << mri_->getName(reg);
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else
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cerr << "%reg" << reg;
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}
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void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
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MachineBasicBlock::iterator mi,
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unsigned MIIdx,
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LiveInterval &interval) {
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DOUT << "\t\tregister: "; DEBUG(printRegName(interval.reg));
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LiveVariables::VarInfo& vi = lv_->getVarInfo(interval.reg);
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// Virtual registers may be defined multiple times (due to phi
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// elimination and 2-addr elimination). Much of what we do only has to be
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// done once for the vreg. We use an empty interval to detect the first
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// time we see a vreg.
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if (interval.empty()) {
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// Get the Idx of the defining instructions.
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unsigned defIndex = getDefIndex(MIIdx);
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VNInfo *ValNo;
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unsigned SrcReg, DstReg;
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if (tii_->isMoveInstr(*mi, SrcReg, DstReg))
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ValNo = interval.getNextValue(defIndex, SrcReg, VNInfoAllocator);
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else if (mi->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG)
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ValNo = interval.getNextValue(defIndex, mi->getOperand(1).getReg(),
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VNInfoAllocator);
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else
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ValNo = interval.getNextValue(defIndex, 0, VNInfoAllocator);
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assert(ValNo->id == 0 && "First value in interval is not 0?");
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// Loop over all of the blocks that the vreg is defined in. There are
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// two cases we have to handle here. The most common case is a vreg
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// whose lifetime is contained within a basic block. In this case there
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// will be a single kill, in MBB, which comes after the definition.
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if (vi.Kills.size() == 1 && vi.Kills[0]->getParent() == mbb) {
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// FIXME: what about dead vars?
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unsigned killIdx;
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if (vi.Kills[0] != mi)
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killIdx = getUseIndex(getInstructionIndex(vi.Kills[0]))+1;
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else
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killIdx = defIndex+1;
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// If the kill happens after the definition, we have an intra-block
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// live range.
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if (killIdx > defIndex) {
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assert(vi.AliveBlocks.none() &&
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"Shouldn't be alive across any blocks!");
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LiveRange LR(defIndex, killIdx, ValNo);
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interval.addRange(LR);
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DOUT << " +" << LR << "\n";
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interval.addKill(ValNo, killIdx);
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return;
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}
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}
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// The other case we handle is when a virtual register lives to the end
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// of the defining block, potentially live across some blocks, then is
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// live into some number of blocks, but gets killed. Start by adding a
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// range that goes from this definition to the end of the defining block.
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LiveRange NewLR(defIndex,
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getInstructionIndex(&mbb->back()) + InstrSlots::NUM,
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ValNo);
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DOUT << " +" << NewLR;
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interval.addRange(NewLR);
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// Iterate over all of the blocks that the variable is completely
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// live in, adding [insrtIndex(begin), instrIndex(end)+4) to the
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// live interval.
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for (unsigned i = 0, e = vi.AliveBlocks.size(); i != e; ++i) {
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if (vi.AliveBlocks[i]) {
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MachineBasicBlock *MBB = mf_->getBlockNumbered(i);
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if (!MBB->empty()) {
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LiveRange LR(getMBBStartIdx(i),
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getInstructionIndex(&MBB->back()) + InstrSlots::NUM,
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ValNo);
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interval.addRange(LR);
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DOUT << " +" << LR;
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}
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}
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}
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// Finally, this virtual register is live from the start of any killing
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// block to the 'use' slot of the killing instruction.
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for (unsigned i = 0, e = vi.Kills.size(); i != e; ++i) {
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MachineInstr *Kill = vi.Kills[i];
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unsigned killIdx = getUseIndex(getInstructionIndex(Kill))+1;
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LiveRange LR(getMBBStartIdx(Kill->getParent()),
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killIdx, ValNo);
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interval.addRange(LR);
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interval.addKill(ValNo, killIdx);
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DOUT << " +" << LR;
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}
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} else {
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// If this is the second time we see a virtual register definition, it
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// must be due to phi elimination or two addr elimination. If this is
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// the result of two address elimination, then the vreg is one of the
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// def-and-use register operand.
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if (mi->isRegReDefinedByTwoAddr(interval.reg)) {
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// If this is a two-address definition, then we have already processed
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// the live range. The only problem is that we didn't realize there
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// are actually two values in the live interval. Because of this we
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// need to take the LiveRegion that defines this register and split it
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// into two values.
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unsigned DefIndex = getDefIndex(getInstructionIndex(vi.DefInst));
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unsigned RedefIndex = getDefIndex(MIIdx);
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const LiveRange *OldLR = interval.getLiveRangeContaining(RedefIndex-1);
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VNInfo *OldValNo = OldLR->valno;
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unsigned OldEnd = OldLR->end;
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// Delete the initial value, which should be short and continuous,
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// because the 2-addr copy must be in the same MBB as the redef.
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interval.removeRange(DefIndex, RedefIndex);
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// Two-address vregs should always only be redefined once. This means
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// that at this point, there should be exactly one value number in it.
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assert(interval.containsOneValue() && "Unexpected 2-addr liveint!");
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// The new value number (#1) is defined by the instruction we claimed
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// defined value #0.
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VNInfo *ValNo = interval.getNextValue(0, 0, VNInfoAllocator);
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interval.copyValNumInfo(ValNo, OldValNo);
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// Value#0 is now defined by the 2-addr instruction.
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OldValNo->def = RedefIndex;
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OldValNo->reg = 0;
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// Add the new live interval which replaces the range for the input copy.
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LiveRange LR(DefIndex, RedefIndex, ValNo);
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DOUT << " replace range with " << LR;
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interval.addRange(LR);
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interval.addKill(ValNo, RedefIndex);
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interval.removeKills(ValNo, RedefIndex, OldEnd);
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// If this redefinition is dead, we need to add a dummy unit live
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// range covering the def slot.
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if (lv_->RegisterDefIsDead(mi, interval.reg))
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interval.addRange(LiveRange(RedefIndex, RedefIndex+1, OldValNo));
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DOUT << " RESULT: ";
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interval.print(DOUT, mri_);
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} else {
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// Otherwise, this must be because of phi elimination. If this is the
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// first redefinition of the vreg that we have seen, go back and change
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// the live range in the PHI block to be a different value number.
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if (interval.containsOneValue()) {
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assert(vi.Kills.size() == 1 &&
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"PHI elimination vreg should have one kill, the PHI itself!");
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// Remove the old range that we now know has an incorrect number.
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VNInfo *VNI = interval.getValNumInfo(0);
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MachineInstr *Killer = vi.Kills[0];
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unsigned Start = getMBBStartIdx(Killer->getParent());
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unsigned End = getUseIndex(getInstructionIndex(Killer))+1;
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DOUT << " Removing [" << Start << "," << End << "] from: ";
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interval.print(DOUT, mri_); DOUT << "\n";
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interval.removeRange(Start, End);
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interval.addKill(VNI, Start+1); // odd # means phi node
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DOUT << " RESULT: "; interval.print(DOUT, mri_);
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// Replace the interval with one of a NEW value number. Note that this
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// value number isn't actually defined by an instruction, weird huh? :)
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LiveRange LR(Start, End, interval.getNextValue(~0, 0, VNInfoAllocator));
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DOUT << " replace range with " << LR;
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interval.addRange(LR);
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interval.addKill(LR.valno, End);
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DOUT << " RESULT: "; interval.print(DOUT, mri_);
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}
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// In the case of PHI elimination, each variable definition is only
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// live until the end of the block. We've already taken care of the
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// rest of the live range.
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unsigned defIndex = getDefIndex(MIIdx);
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VNInfo *ValNo;
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unsigned SrcReg, DstReg;
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if (tii_->isMoveInstr(*mi, SrcReg, DstReg))
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ValNo = interval.getNextValue(defIndex, SrcReg, VNInfoAllocator);
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else if (mi->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG)
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ValNo = interval.getNextValue(defIndex, mi->getOperand(1).getReg(),
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VNInfoAllocator);
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else
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ValNo = interval.getNextValue(defIndex, 0, VNInfoAllocator);
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unsigned killIndex = getInstructionIndex(&mbb->back()) + InstrSlots::NUM;
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LiveRange LR(defIndex, killIndex, ValNo);
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interval.addRange(LR);
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interval.addKill(ValNo, killIndex-1); // odd # means phi node
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DOUT << " +" << LR;
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}
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}
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DOUT << '\n';
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}
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void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock *MBB,
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MachineBasicBlock::iterator mi,
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unsigned MIIdx,
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LiveInterval &interval,
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unsigned SrcReg) {
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// A physical register cannot be live across basic block, so its
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// lifetime must end somewhere in its defining basic block.
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DOUT << "\t\tregister: "; DEBUG(printRegName(interval.reg));
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unsigned baseIndex = MIIdx;
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unsigned start = getDefIndex(baseIndex);
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unsigned end = start;
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// If it is not used after definition, it is considered dead at
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// the instruction defining it. Hence its interval is:
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// [defSlot(def), defSlot(def)+1)
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if (lv_->RegisterDefIsDead(mi, interval.reg)) {
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DOUT << " dead";
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end = getDefIndex(start) + 1;
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goto exit;
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}
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// If it is not dead on definition, it must be killed by a
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// subsequent instruction. Hence its interval is:
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// [defSlot(def), useSlot(kill)+1)
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while (++mi != MBB->end()) {
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baseIndex += InstrSlots::NUM;
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if (lv_->KillsRegister(mi, interval.reg)) {
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DOUT << " killed";
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end = getUseIndex(baseIndex) + 1;
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goto exit;
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} else if (lv_->ModifiesRegister(mi, interval.reg)) {
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// Another instruction redefines the register before it is ever read.
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// Then the register is essentially dead at the instruction that defines
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// it. Hence its interval is:
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// [defSlot(def), defSlot(def)+1)
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DOUT << " dead";
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end = getDefIndex(start) + 1;
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goto exit;
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}
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}
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// The only case we should have a dead physreg here without a killing or
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// instruction where we know it's dead is if it is live-in to the function
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// and never used.
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assert(!SrcReg && "physreg was not killed in defining block!");
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end = getDefIndex(start) + 1; // It's dead.
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exit:
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assert(start < end && "did not find end of interval?");
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|
|
// Already exists? Extend old live interval.
|
|
LiveInterval::iterator OldLR = interval.FindLiveRangeContaining(start);
|
|
VNInfo *ValNo = (OldLR != interval.end())
|
|
? OldLR->valno : interval.getNextValue(start, SrcReg, VNInfoAllocator);
|
|
LiveRange LR(start, end, ValNo);
|
|
interval.addRange(LR);
|
|
interval.addKill(LR.valno, end);
|
|
DOUT << " +" << LR << '\n';
|
|
}
|
|
|
|
void LiveIntervals::handleRegisterDef(MachineBasicBlock *MBB,
|
|
MachineBasicBlock::iterator MI,
|
|
unsigned MIIdx,
|
|
unsigned reg) {
|
|
if (MRegisterInfo::isVirtualRegister(reg))
|
|
handleVirtualRegisterDef(MBB, MI, MIIdx, getOrCreateInterval(reg));
|
|
else if (allocatableRegs_[reg]) {
|
|
unsigned SrcReg, DstReg;
|
|
if (MI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG)
|
|
SrcReg = MI->getOperand(1).getReg();
|
|
else if (!tii_->isMoveInstr(*MI, SrcReg, DstReg))
|
|
SrcReg = 0;
|
|
handlePhysicalRegisterDef(MBB, MI, MIIdx, getOrCreateInterval(reg), SrcReg);
|
|
// Def of a register also defines its sub-registers.
|
|
for (const unsigned* AS = mri_->getSubRegisters(reg); *AS; ++AS)
|
|
// Avoid processing some defs more than once.
|
|
if (!MI->findRegisterDefOperand(*AS))
|
|
handlePhysicalRegisterDef(MBB, MI, MIIdx, getOrCreateInterval(*AS), 0);
|
|
}
|
|
}
|
|
|
|
void LiveIntervals::handleLiveInRegister(MachineBasicBlock *MBB,
|
|
unsigned MIIdx,
|
|
LiveInterval &interval, bool isAlias) {
|
|
DOUT << "\t\tlivein register: "; DEBUG(printRegName(interval.reg));
|
|
|
|
// Look for kills, if it reaches a def before it's killed, then it shouldn't
|
|
// be considered a livein.
|
|
MachineBasicBlock::iterator mi = MBB->begin();
|
|
unsigned baseIndex = MIIdx;
|
|
unsigned start = baseIndex;
|
|
unsigned end = start;
|
|
while (mi != MBB->end()) {
|
|
if (lv_->KillsRegister(mi, interval.reg)) {
|
|
DOUT << " killed";
|
|
end = getUseIndex(baseIndex) + 1;
|
|
goto exit;
|
|
} else if (lv_->ModifiesRegister(mi, interval.reg)) {
|
|
// Another instruction redefines the register before it is ever read.
|
|
// Then the register is essentially dead at the instruction that defines
|
|
// it. Hence its interval is:
|
|
// [defSlot(def), defSlot(def)+1)
|
|
DOUT << " dead";
|
|
end = getDefIndex(start) + 1;
|
|
goto exit;
|
|
}
|
|
|
|
baseIndex += InstrSlots::NUM;
|
|
++mi;
|
|
}
|
|
|
|
exit:
|
|
// Live-in register might not be used at all.
|
|
if (end == MIIdx) {
|
|
if (isAlias) {
|
|
DOUT << " dead";
|
|
end = getDefIndex(MIIdx) + 1;
|
|
} else {
|
|
DOUT << " live through";
|
|
end = baseIndex;
|
|
}
|
|
}
|
|
|
|
LiveRange LR(start, end, interval.getNextValue(start, 0, VNInfoAllocator));
|
|
interval.addRange(LR);
|
|
interval.addKill(LR.valno, end);
|
|
DOUT << " +" << LR << '\n';
|
|
}
|
|
|
|
/// computeIntervals - computes the live intervals for virtual
|
|
/// registers. for some ordering of the machine instructions [1,N] a
|
|
/// live interval is an interval [i, j) where 1 <= i <= j < N for
|
|
/// which a variable is live
|
|
void LiveIntervals::computeIntervals() {
|
|
DOUT << "********** COMPUTING LIVE INTERVALS **********\n"
|
|
<< "********** Function: "
|
|
<< ((Value*)mf_->getFunction())->getName() << '\n';
|
|
// Track the index of the current machine instr.
|
|
unsigned MIIndex = 0;
|
|
for (MachineFunction::iterator MBBI = mf_->begin(), E = mf_->end();
|
|
MBBI != E; ++MBBI) {
|
|
MachineBasicBlock *MBB = MBBI;
|
|
DOUT << ((Value*)MBB->getBasicBlock())->getName() << ":\n";
|
|
|
|
MachineBasicBlock::iterator MI = MBB->begin(), miEnd = MBB->end();
|
|
|
|
// Create intervals for live-ins to this BB first.
|
|
for (MachineBasicBlock::const_livein_iterator LI = MBB->livein_begin(),
|
|
LE = MBB->livein_end(); LI != LE; ++LI) {
|
|
handleLiveInRegister(MBB, MIIndex, getOrCreateInterval(*LI));
|
|
// Multiple live-ins can alias the same register.
|
|
for (const unsigned* AS = mri_->getSubRegisters(*LI); *AS; ++AS)
|
|
if (!hasInterval(*AS))
|
|
handleLiveInRegister(MBB, MIIndex, getOrCreateInterval(*AS),
|
|
true);
|
|
}
|
|
|
|
for (; MI != miEnd; ++MI) {
|
|
DOUT << MIIndex << "\t" << *MI;
|
|
|
|
// Handle defs.
|
|
for (int i = MI->getNumOperands() - 1; i >= 0; --i) {
|
|
MachineOperand &MO = MI->getOperand(i);
|
|
// handle register defs - build intervals
|
|
if (MO.isRegister() && MO.getReg() && MO.isDef())
|
|
handleRegisterDef(MBB, MI, MIIndex, MO.getReg());
|
|
}
|
|
|
|
MIIndex += InstrSlots::NUM;
|
|
}
|
|
}
|
|
}
|
|
|
|
bool LiveIntervals::findLiveInMBBs(const LiveRange &LR,
|
|
SmallVectorImpl<MachineBasicBlock*> &MBBs) const {
|
|
std::vector<IdxMBBPair>::const_iterator I =
|
|
std::lower_bound(Idx2MBBMap.begin(), Idx2MBBMap.end(), LR.start);
|
|
|
|
bool ResVal = false;
|
|
while (I != Idx2MBBMap.end()) {
|
|
if (LR.end <= I->first)
|
|
break;
|
|
MBBs.push_back(I->second);
|
|
ResVal = true;
|
|
++I;
|
|
}
|
|
return ResVal;
|
|
}
|
|
|
|
|
|
LiveInterval LiveIntervals::createInterval(unsigned reg) {
|
|
float Weight = MRegisterInfo::isPhysicalRegister(reg) ?
|
|
HUGE_VALF : 0.0F;
|
|
return LiveInterval(reg, Weight);
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Register allocator hooks.
|
|
//
|
|
|
|
/// isReMaterializable - Returns true if the definition MI of the specified
|
|
/// val# of the specified interval is re-materializable.
|
|
bool LiveIntervals::isReMaterializable(const LiveInterval &li,
|
|
const VNInfo *ValNo, MachineInstr *MI) {
|
|
if (DisableReMat)
|
|
return false;
|
|
|
|
if (tii_->isTriviallyReMaterializable(MI))
|
|
return true;
|
|
|
|
int FrameIdx = 0;
|
|
if (!tii_->isLoadFromStackSlot(MI, FrameIdx) ||
|
|
!mf_->getFrameInfo()->isFixedObjectIndex(FrameIdx))
|
|
return false;
|
|
|
|
// This is a load from fixed stack slot. It can be rematerialized unless it's
|
|
// re-defined by a two-address instruction.
|
|
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
|
|
i != e; ++i) {
|
|
const VNInfo *VNI = *i;
|
|
if (VNI == ValNo)
|
|
continue;
|
|
unsigned DefIdx = VNI->def;
|
|
if (DefIdx == ~1U)
|
|
continue; // Dead val#.
|
|
MachineInstr *DefMI = (DefIdx == ~0u)
|
|
? NULL : getInstructionFromIndex(DefIdx);
|
|
if (DefMI && DefMI->isRegReDefinedByTwoAddr(li.reg))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
|
|
/// slot / to reg or any rematerialized load into ith operand of specified
|
|
/// MI. If it is successul, MI is updated with the newly created MI and
|
|
/// returns true.
|
|
bool LiveIntervals::tryFoldMemoryOperand(MachineInstr* &MI,
|
|
VirtRegMap &vrm,
|
|
MachineInstr *DefMI,
|
|
unsigned index, unsigned i,
|
|
bool isSS, int slot, unsigned reg) {
|
|
MachineInstr *fmi = isSS
|
|
? mri_->foldMemoryOperand(MI, i, slot)
|
|
: mri_->foldMemoryOperand(MI, i, DefMI);
|
|
if (fmi) {
|
|
// Attempt to fold the memory reference into the instruction. If
|
|
// we can do this, we don't need to insert spill code.
|
|
if (lv_)
|
|
lv_->instructionChanged(MI, fmi);
|
|
else
|
|
LiveVariables::transferKillDeadInfo(MI, fmi, mri_);
|
|
MachineBasicBlock &MBB = *MI->getParent();
|
|
vrm.virtFolded(reg, MI, i, fmi);
|
|
vrm.transferSpillPts(MI, fmi);
|
|
mi2iMap_.erase(MI);
|
|
i2miMap_[index/InstrSlots::NUM] = fmi;
|
|
mi2iMap_[fmi] = index;
|
|
MI = MBB.insert(MBB.erase(MI), fmi);
|
|
++numFolded;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool LiveIntervals::intervalIsInOneMBB(const LiveInterval &li) const {
|
|
SmallPtrSet<MachineBasicBlock*, 4> MBBs;
|
|
for (LiveInterval::Ranges::const_iterator
|
|
I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
|
|
std::vector<IdxMBBPair>::const_iterator II =
|
|
std::lower_bound(Idx2MBBMap.begin(), Idx2MBBMap.end(), I->start);
|
|
if (II == Idx2MBBMap.end())
|
|
continue;
|
|
if (I->end > II->first) // crossing a MBB.
|
|
return false;
|
|
MBBs.insert(II->second);
|
|
if (MBBs.size() > 1)
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static
|
|
bool hasALaterUse(MachineBasicBlock *MBB, MachineInstr *MI, unsigned Reg) {
|
|
MachineBasicBlock::iterator I = MI;
|
|
if (I == MBB->end())
|
|
return false;
|
|
++I;
|
|
while (I != MBB->end()) {
|
|
if (I->findRegisterUseOperandIdx(Reg) != -1)
|
|
return true;
|
|
++I;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// rewriteInstructionForSpills, rewriteInstructionsForSpills - Helper functions
|
|
/// for addIntervalsForSpills to rewrite uses / defs for the given live range.
|
|
void LiveIntervals::
|
|
rewriteInstructionForSpills(const LiveInterval &li, bool TrySplit,
|
|
unsigned id, unsigned index, unsigned end, MachineInstr *MI,
|
|
MachineInstr *ReMatOrigDefMI, MachineInstr *ReMatDefMI,
|
|
unsigned Slot, int LdSlot,
|
|
bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
|
|
VirtRegMap &vrm, SSARegMap *RegMap,
|
|
const TargetRegisterClass* rc,
|
|
SmallVector<int, 4> &ReMatIds,
|
|
unsigned &NewVReg, bool &HasDef, bool &HasUse,
|
|
const LoopInfo *loopInfo, std::vector<unsigned> &NewVRegs,
|
|
std::vector<LiveInterval*> &NewLIs) {
|
|
RestartInstruction:
|
|
for (unsigned i = 0; i != MI->getNumOperands(); ++i) {
|
|
MachineOperand& mop = MI->getOperand(i);
|
|
if (!mop.isRegister())
|
|
continue;
|
|
unsigned Reg = mop.getReg();
|
|
unsigned RegI = Reg;
|
|
if (Reg == 0 || MRegisterInfo::isPhysicalRegister(Reg))
|
|
continue;
|
|
unsigned SubIdx = mop.getSubReg();
|
|
bool isSubReg = SubIdx != 0;
|
|
if (Reg != li.reg)
|
|
continue;
|
|
|
|
bool TryFold = !DefIsReMat;
|
|
bool FoldSS = true;
|
|
int FoldSlot = Slot;
|
|
if (DefIsReMat) {
|
|
// If this is the rematerializable definition MI itself and
|
|
// all of its uses are rematerialized, simply delete it.
|
|
if (MI == ReMatOrigDefMI && CanDelete) {
|
|
RemoveMachineInstrFromMaps(MI);
|
|
MI->eraseFromParent();
|
|
break;
|
|
}
|
|
|
|
// If def for this use can't be rematerialized, then try folding.
|
|
TryFold = !ReMatOrigDefMI ||
|
|
(ReMatOrigDefMI && (MI == ReMatOrigDefMI || isLoad));
|
|
if (isLoad) {
|
|
// Try fold loads (from stack slot, constant pool, etc.) into uses.
|
|
FoldSS = isLoadSS;
|
|
FoldSlot = LdSlot;
|
|
}
|
|
}
|
|
|
|
// If we are splitting live intervals, only fold if it's 1) the first
|
|
// use and it's a kill or 2) there isn't another use later in this MBB.
|
|
TryFold &= NewVReg == 0;
|
|
if (TryFold && TrySplit)
|
|
// Do not fold store into def here if we are splitting. We'll find an
|
|
// optimal point to insert a store later.
|
|
if (HasDef || mop.isDef() ||
|
|
(!mop.isKill() && hasALaterUse(MI->getParent(), MI, li.reg)))
|
|
TryFold = false;
|
|
|
|
// FIXME: fold subreg use
|
|
if (!isSubReg && TryFold &&
|
|
tryFoldMemoryOperand(MI, vrm, ReMatDefMI, index, i, FoldSS, FoldSlot,
|
|
Reg))
|
|
// Folding the load/store can completely change the instruction in
|
|
// unpredictable ways, rescan it from the beginning.
|
|
goto RestartInstruction;
|
|
|
|
// Create a new virtual register for the spill interval.
|
|
bool CreatedNewVReg = false;
|
|
if (NewVReg == 0) {
|
|
NewVReg = RegMap->createVirtualRegister(rc);
|
|
vrm.grow();
|
|
CreatedNewVReg = true;
|
|
}
|
|
mop.setReg(NewVReg);
|
|
|
|
// Scan all of the operands of this instruction rewriting operands
|
|
// to use NewVReg instead of li.reg as appropriate. We do this for
|
|
// two reasons:
|
|
//
|
|
// 1. If the instr reads the same spilled vreg multiple times, we
|
|
// want to reuse the NewVReg.
|
|
// 2. If the instr is a two-addr instruction, we are required to
|
|
// keep the src/dst regs pinned.
|
|
//
|
|
// Keep track of whether we replace a use and/or def so that we can
|
|
// create the spill interval with the appropriate range.
|
|
|
|
HasUse = mop.isUse();
|
|
HasDef = mop.isDef();
|
|
for (unsigned j = i+1, e = MI->getNumOperands(); j != e; ++j) {
|
|
if (!MI->getOperand(j).isRegister())
|
|
continue;
|
|
unsigned RegJ = MI->getOperand(j).getReg();
|
|
if (RegJ == 0 || MRegisterInfo::isPhysicalRegister(RegJ))
|
|
continue;
|
|
if (RegJ == RegI) {
|
|
MI->getOperand(j).setReg(NewVReg);
|
|
HasUse |= MI->getOperand(j).isUse();
|
|
HasDef |= MI->getOperand(j).isDef();
|
|
}
|
|
}
|
|
|
|
if (CreatedNewVReg) {
|
|
if (DefIsReMat) {
|
|
vrm.setVirtIsReMaterialized(NewVReg, ReMatDefMI/*, CanDelete*/);
|
|
if (ReMatIds[id] == VirtRegMap::MAX_STACK_SLOT) {
|
|
// Each valnum may have its own remat id.
|
|
ReMatIds[id] = vrm.assignVirtReMatId(NewVReg);
|
|
} else {
|
|
vrm.assignVirtReMatId(NewVReg, ReMatIds[id]);
|
|
}
|
|
if (!CanDelete || (HasUse && HasDef)) {
|
|
// If this is a two-addr instruction then its use operands are
|
|
// rematerializable but its def is not. It should be assigned a
|
|
// stack slot.
|
|
vrm.assignVirt2StackSlot(NewVReg, Slot);
|
|
}
|
|
} else {
|
|
vrm.assignVirt2StackSlot(NewVReg, Slot);
|
|
}
|
|
}
|
|
|
|
// create a new register interval for this spill / remat.
|
|
LiveInterval &nI = getOrCreateInterval(NewVReg);
|
|
if (CreatedNewVReg) {
|
|
NewLIs.push_back(&nI);
|
|
NewVRegs[MI->getParent()->getNumber()] = NewVReg;
|
|
if (TrySplit)
|
|
vrm.setIsSplitFromReg(NewVReg, li.reg);
|
|
}
|
|
|
|
if (HasUse) {
|
|
if (CreatedNewVReg) {
|
|
LiveRange LR(getLoadIndex(index), getUseIndex(index)+1,
|
|
nI.getNextValue(~0U, 0, VNInfoAllocator));
|
|
DOUT << " +" << LR;
|
|
nI.addRange(LR);
|
|
} else {
|
|
// Extend the split live interval to this def / use.
|
|
unsigned End = getUseIndex(index)+1;
|
|
LiveRange LR(nI.ranges[nI.ranges.size()-1].end, End,
|
|
nI.getValNumInfo(nI.getNumValNums()-1));
|
|
DOUT << " +" << LR;
|
|
nI.addRange(LR);
|
|
}
|
|
}
|
|
if (HasDef) {
|
|
LiveRange LR(getDefIndex(index), getStoreIndex(index),
|
|
nI.getNextValue(~0U, 0, VNInfoAllocator));
|
|
DOUT << " +" << LR;
|
|
nI.addRange(LR);
|
|
}
|
|
|
|
DOUT << "\t\t\t\tAdded new interval: ";
|
|
nI.print(DOUT, mri_);
|
|
DOUT << '\n';
|
|
}
|
|
}
|
|
|
|
bool LiveIntervals::anyKillInMBBAfterIdx(const LiveInterval &li,
|
|
MachineBasicBlock *MBB, unsigned Idx,
|
|
const VNInfo *VNI) const {
|
|
unsigned End = getMBBEndIdx(MBB);
|
|
if (VNI) {
|
|
for (unsigned j = 0, ee = VNI->kills.size(); j != ee; ++j) {
|
|
unsigned KillIdx = VNI->kills[j];
|
|
if (KillIdx > Idx && KillIdx < End)
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Look at all the VNInfo's.
|
|
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
|
|
i != e; ++i) {
|
|
const VNInfo *VNI = *i;
|
|
for (unsigned j = 0, ee = VNI->kills.size(); j != ee; ++j) {
|
|
unsigned KillIdx = VNI->kills[j];
|
|
if (KillIdx > Idx && KillIdx < End)
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void LiveIntervals::
|
|
rewriteInstructionsForSpills(const LiveInterval &li, bool TrySplit,
|
|
LiveInterval::Ranges::const_iterator &I,
|
|
MachineInstr *ReMatOrigDefMI, MachineInstr *ReMatDefMI,
|
|
unsigned Slot, int LdSlot,
|
|
bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
|
|
VirtRegMap &vrm, SSARegMap *RegMap,
|
|
const TargetRegisterClass* rc,
|
|
SmallVector<int, 4> &ReMatIds,
|
|
const LoopInfo *loopInfo,
|
|
BitVector &SpillMBBs,
|
|
std::vector<std::pair<int, unsigned> > &SpillIdxes,
|
|
std::vector<unsigned> &NewVRegs,
|
|
std::vector<LiveInterval*> &NewLIs) {
|
|
unsigned NewVReg = 0;
|
|
unsigned index = getBaseIndex(I->start);
|
|
unsigned end = getBaseIndex(I->end-1) + InstrSlots::NUM;
|
|
bool TrySplitMI = TrySplit && vrm.getPreSplitReg(li.reg) == 0;
|
|
for (; index != end; index += InstrSlots::NUM) {
|
|
// skip deleted instructions
|
|
while (index != end && !getInstructionFromIndex(index))
|
|
index += InstrSlots::NUM;
|
|
if (index == end) break;
|
|
|
|
MachineInstr *MI = getInstructionFromIndex(index);
|
|
MachineBasicBlock *MBB = MI->getParent();
|
|
NewVReg = !TrySplitMI ? 0 : NewVRegs[MBB->getNumber()];
|
|
bool IsNew = NewVReg == 0;
|
|
bool HasDef = false;
|
|
bool HasUse = false;
|
|
rewriteInstructionForSpills(li, TrySplitMI, I->valno->id, index, end,
|
|
MI, ReMatOrigDefMI, ReMatDefMI, Slot, LdSlot,
|
|
isLoad, isLoadSS, DefIsReMat, CanDelete, vrm,
|
|
RegMap, rc, ReMatIds, NewVReg, HasDef, HasUse,
|
|
loopInfo, NewVRegs, NewLIs);
|
|
if (!HasDef && !HasUse)
|
|
continue;
|
|
|
|
// Update weight of spill interval.
|
|
LiveInterval &nI = getOrCreateInterval(NewVReg);
|
|
if (!TrySplitMI)
|
|
// The spill weight is now infinity as it cannot be spilled again.
|
|
nI.weight = HUGE_VALF;
|
|
else {
|
|
// Keep track of the last def in each MBB.
|
|
if (HasDef) {
|
|
if (MI != ReMatOrigDefMI || !CanDelete) {
|
|
// If this is a two-address code, then this index probably starts a
|
|
// VNInfo so we should examine all the VNInfo's.
|
|
bool HasKill = HasUse
|
|
? anyKillInMBBAfterIdx(li, MBB, getDefIndex(index))
|
|
: anyKillInMBBAfterIdx(li, MBB, getDefIndex(index), I->valno);
|
|
if (!HasKill) {
|
|
unsigned MBBId = MBB->getNumber();
|
|
if ((int)index > SpillIdxes[MBBId].first)
|
|
// High bit specify whether this spill ought to be folded if
|
|
// possible.
|
|
SpillIdxes[MBBId] = std::make_pair(index, NewVReg | (1 << 31));
|
|
SpillMBBs.set(MBBId);
|
|
}
|
|
}
|
|
if (!IsNew) {
|
|
// It this interval hasn't been assigned a stack slot
|
|
// (because earlier def is remat), do it now.
|
|
int SS = vrm.getStackSlot(NewVReg);
|
|
if (SS != (int)Slot) {
|
|
assert(SS == VirtRegMap::NO_STACK_SLOT);
|
|
vrm.assignVirt2StackSlot(NewVReg, Slot);
|
|
}
|
|
}
|
|
} else if (HasUse) {
|
|
// Use(s) following the last def, it's not safe to fold the spill.
|
|
unsigned MBBId = MBB->getNumber();
|
|
if ((SpillIdxes[MBBId].second & ((1<<31)-1)) == NewVReg &&
|
|
(int)getUseIndex(index) > SpillIdxes[MBBId].first)
|
|
SpillIdxes[MBBId].second &= (1<<31)-1;
|
|
}
|
|
|
|
// Update spill weight.
|
|
unsigned loopDepth = loopInfo->getLoopDepth(MBB->getBasicBlock());
|
|
nI.weight += getSpillWeight(HasDef, HasUse, loopDepth);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
std::vector<LiveInterval*> LiveIntervals::
|
|
addIntervalsForSpills(const LiveInterval &li,
|
|
const LoopInfo *loopInfo, VirtRegMap &vrm) {
|
|
// Since this is called after the analysis is done we don't know if
|
|
// LiveVariables is available
|
|
lv_ = getAnalysisToUpdate<LiveVariables>();
|
|
|
|
assert(li.weight != HUGE_VALF &&
|
|
"attempt to spill already spilled interval!");
|
|
|
|
DOUT << "\t\t\t\tadding intervals for spills for interval: ";
|
|
li.print(DOUT, mri_);
|
|
DOUT << '\n';
|
|
|
|
// Each bit specify whether it a spill is required in the MBB.
|
|
BitVector SpillMBBs(mf_->getNumBlockIDs());
|
|
std::vector<std::pair<int, unsigned> > SpillIdxes(mf_->getNumBlockIDs(),
|
|
std::make_pair(-1,0));
|
|
std::vector<unsigned> NewVRegs(mf_->getNumBlockIDs(), 0);
|
|
std::vector<LiveInterval*> NewLIs;
|
|
SSARegMap *RegMap = mf_->getSSARegMap();
|
|
const TargetRegisterClass* rc = RegMap->getRegClass(li.reg);
|
|
|
|
unsigned NumValNums = li.getNumValNums();
|
|
SmallVector<MachineInstr*, 4> ReMatDefs;
|
|
ReMatDefs.resize(NumValNums, NULL);
|
|
SmallVector<MachineInstr*, 4> ReMatOrigDefs;
|
|
ReMatOrigDefs.resize(NumValNums, NULL);
|
|
SmallVector<int, 4> ReMatIds;
|
|
ReMatIds.resize(NumValNums, VirtRegMap::MAX_STACK_SLOT);
|
|
BitVector ReMatDelete(NumValNums);
|
|
unsigned Slot = VirtRegMap::MAX_STACK_SLOT;
|
|
|
|
// Spilling a split live interval. It cannot be split any further. Also,
|
|
// it's also guaranteed to be a single val# / range interval.
|
|
if (vrm.getPreSplitReg(li.reg)) {
|
|
vrm.setIsSplitFromReg(li.reg, 0);
|
|
bool DefIsReMat = vrm.isReMaterialized(li.reg);
|
|
Slot = vrm.getStackSlot(li.reg);
|
|
assert(Slot != VirtRegMap::MAX_STACK_SLOT);
|
|
MachineInstr *ReMatDefMI = DefIsReMat ?
|
|
vrm.getReMaterializedMI(li.reg) : NULL;
|
|
int LdSlot = 0;
|
|
bool isLoadSS = DefIsReMat && tii_->isLoadFromStackSlot(ReMatDefMI, LdSlot);
|
|
bool isLoad = isLoadSS ||
|
|
(DefIsReMat && (ReMatDefMI->getInstrDescriptor()->Flags & M_LOAD_FLAG));
|
|
vrm.removeAllSpillPtsForReg(li.reg);
|
|
bool IsFirstRange = true;
|
|
for (LiveInterval::Ranges::const_iterator
|
|
I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
|
|
// If this is a split live interval with multiple ranges, it means there
|
|
// are two-address instructions that re-defined the value. Only the
|
|
// first def can be rematerialized!
|
|
if (IsFirstRange) {
|
|
rewriteInstructionsForSpills(li, false, I, NULL, ReMatDefMI,
|
|
Slot, LdSlot, isLoad, isLoadSS, DefIsReMat,
|
|
false, vrm, RegMap, rc, ReMatIds,
|
|
loopInfo, SpillMBBs, SpillIdxes, NewVRegs, NewLIs);
|
|
} else {
|
|
rewriteInstructionsForSpills(li, false, I, NULL, 0,
|
|
Slot, 0, false, false, false,
|
|
false, vrm, RegMap, rc, ReMatIds,
|
|
loopInfo, SpillMBBs, SpillIdxes, NewVRegs, NewLIs);
|
|
}
|
|
IsFirstRange = false;
|
|
}
|
|
return NewLIs;
|
|
}
|
|
|
|
bool TrySplit = SplitAtBB && !intervalIsInOneMBB(li);
|
|
bool NeedStackSlot = false;
|
|
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
|
|
i != e; ++i) {
|
|
const VNInfo *VNI = *i;
|
|
unsigned VN = VNI->id;
|
|
unsigned DefIdx = VNI->def;
|
|
if (DefIdx == ~1U)
|
|
continue; // Dead val#.
|
|
// Is the def for the val# rematerializable?
|
|
MachineInstr *ReMatDefMI = (DefIdx == ~0u)
|
|
? 0 : getInstructionFromIndex(DefIdx);
|
|
if (ReMatDefMI && isReMaterializable(li, VNI, ReMatDefMI)) {
|
|
// Remember how to remat the def of this val#.
|
|
ReMatOrigDefs[VN] = ReMatDefMI;
|
|
// Original def may be modified so we have to make a copy here. vrm must
|
|
// delete these!
|
|
ReMatDefs[VN] = ReMatDefMI = ReMatDefMI->clone();
|
|
vrm.setVirtIsReMaterialized(li.reg, ReMatDefMI);
|
|
|
|
bool CanDelete = true;
|
|
for (unsigned j = 0, ee = VNI->kills.size(); j != ee; ++j) {
|
|
unsigned KillIdx = VNI->kills[j];
|
|
MachineInstr *KillMI = (KillIdx & 1)
|
|
? NULL : getInstructionFromIndex(KillIdx);
|
|
// Kill is a phi node, not all of its uses can be rematerialized.
|
|
// It must not be deleted.
|
|
if (!KillMI) {
|
|
CanDelete = false;
|
|
// Need a stack slot if there is any live range where uses cannot be
|
|
// rematerialized.
|
|
NeedStackSlot = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (CanDelete)
|
|
ReMatDelete.set(VN);
|
|
} else {
|
|
// Need a stack slot if there is any live range where uses cannot be
|
|
// rematerialized.
|
|
NeedStackSlot = true;
|
|
}
|
|
}
|
|
|
|
// One stack slot per live interval.
|
|
if (NeedStackSlot && vrm.getPreSplitReg(li.reg) == 0)
|
|
Slot = vrm.assignVirt2StackSlot(li.reg);
|
|
|
|
|
|
// Create new intervals and rewrite defs and uses.
|
|
for (LiveInterval::Ranges::const_iterator
|
|
I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
|
|
MachineInstr *ReMatDefMI = ReMatDefs[I->valno->id];
|
|
MachineInstr *ReMatOrigDefMI = ReMatOrigDefs[I->valno->id];
|
|
bool DefIsReMat = ReMatDefMI != NULL;
|
|
bool CanDelete = ReMatDelete[I->valno->id];
|
|
int LdSlot = 0;
|
|
bool isLoadSS = DefIsReMat && tii_->isLoadFromStackSlot(ReMatDefMI, LdSlot);
|
|
bool isLoad = isLoadSS ||
|
|
(DefIsReMat && (ReMatDefMI->getInstrDescriptor()->Flags & M_LOAD_FLAG));
|
|
rewriteInstructionsForSpills(li, TrySplit, I, ReMatOrigDefMI, ReMatDefMI,
|
|
Slot, LdSlot, isLoad, isLoadSS, DefIsReMat,
|
|
CanDelete, vrm, RegMap, rc, ReMatIds,
|
|
loopInfo, SpillMBBs, SpillIdxes, NewVRegs, NewLIs);
|
|
}
|
|
|
|
// Insert spills if we are splitting.
|
|
if (TrySplit && NeedStackSlot) {
|
|
int Id = SpillMBBs.find_first();
|
|
while (Id != -1) {
|
|
unsigned index = SpillIdxes[Id].first;
|
|
unsigned VReg = SpillIdxes[Id].second & ((1 << 31)-1);
|
|
bool TryFold = SpillIdxes[Id].second & (1 << 31);
|
|
MachineInstr *MI = getInstructionFromIndex(index);
|
|
int OpIdx = -1;
|
|
if (TryFold) {
|
|
for (unsigned j = 0, ee = MI->getNumOperands(); j != ee; ++j) {
|
|
MachineOperand &MO = MI->getOperand(j);
|
|
if (!MO.isRegister() || MO.getReg() != VReg)
|
|
continue;
|
|
if (MO.isUse()) {
|
|
// Can't fold if it's two-address code.
|
|
OpIdx = -1;
|
|
break;
|
|
}
|
|
OpIdx = (int)j;
|
|
}
|
|
}
|
|
// Fold the store into the def if possible.
|
|
if (OpIdx == -1 ||
|
|
!tryFoldMemoryOperand(MI, vrm, NULL, index, OpIdx, true, Slot, VReg))
|
|
// Else tell the spiller to issue a store for us.
|
|
vrm.addSpillPoint(VReg, MI);
|
|
Id = SpillMBBs.find_next(Id);
|
|
}
|
|
}
|
|
|
|
// Finalize spill weights.
|
|
if (TrySplit)
|
|
for (unsigned i = 0, e = NewLIs.size(); i != e; ++i)
|
|
NewLIs[i]->weight /= NewLIs[i]->getSize();
|
|
|
|
return NewLIs;
|
|
}
|