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https://github.com/c64scene-ar/llvm-6502.git
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c64379da07
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122444 91177308-0d34-0410-b5e6-96231b3b80d8
1302 lines
47 KiB
C++
1302 lines
47 KiB
C++
//===---------- SplitKit.cpp - Toolkit for splitting live ranges ----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the SplitAnalysis class as well as mutator functions for
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// live range splitting.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "regalloc"
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#include "SplitKit.h"
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#include "LiveRangeEdit.h"
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#include "VirtRegMap.h"
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#include "llvm/CodeGen/CalcSpillWeights.h"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineLoopInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.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/Support/GraphWriter.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetMachine.h"
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using namespace llvm;
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static cl::opt<bool>
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AllowSplit("spiller-splits-edges",
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cl::desc("Allow critical edge splitting during spilling"));
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//===----------------------------------------------------------------------===//
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// Edge Bundles
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//===----------------------------------------------------------------------===//
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/// compute - Compute the edge bundles for MF. Bundles depend only on the CFG.
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void EdgeBundles::compute(const MachineFunction *mf) {
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MF = mf;
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EC.clear();
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EC.grow(2 * MF->size());
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for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
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++I) {
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const MachineBasicBlock &MBB = *I;
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unsigned OutE = 2 * MBB.getNumber() + 1;
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// Join the outgoing bundle with the ingoing bundles of all successors.
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for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
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SE = MBB.succ_end(); SI != SE; ++SI)
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EC.join(OutE, 2 * (*SI)->getNumber());
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}
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EC.compress();
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}
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/// view - Visualize the annotated bipartite CFG with Graphviz.
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void EdgeBundles::view() const {
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ViewGraph(*this, "EdgeBundles");
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}
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/// Specialize WriteGraph, the standard implementation won't work.
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raw_ostream &llvm::WriteGraph(raw_ostream &O, const EdgeBundles &G,
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bool ShortNames,
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const std::string &Title) {
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const MachineFunction *MF = G.getMachineFunction();
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O << "digraph {\n";
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for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
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I != E; ++I) {
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unsigned BB = I->getNumber();
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O << "\t\"BB#" << BB << "\" [ shape=box ]\n"
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<< '\t' << G.getBundle(BB, false) << " -> \"BB#" << BB << "\"\n"
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<< "\t\"BB#" << BB << "\" -> " << G.getBundle(BB, true) << '\n';
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for (MachineBasicBlock::const_succ_iterator SI = I->succ_begin(),
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SE = I->succ_end(); SI != SE; ++SI)
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O << "\t\"BB#" << BB << "\" -> \"BB#" << (*SI)->getNumber()
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<< "\" [ color=lightgray ]\n";
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}
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O << "}\n";
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return O;
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}
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//===----------------------------------------------------------------------===//
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// Split Analysis
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//===----------------------------------------------------------------------===//
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SplitAnalysis::SplitAnalysis(const MachineFunction &mf,
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const LiveIntervals &lis,
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const MachineLoopInfo &mli)
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: mf_(mf),
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lis_(lis),
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loops_(mli),
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tii_(*mf.getTarget().getInstrInfo()),
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curli_(0) {}
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void SplitAnalysis::clear() {
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usingInstrs_.clear();
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usingBlocks_.clear();
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usingLoops_.clear();
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curli_ = 0;
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}
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bool SplitAnalysis::canAnalyzeBranch(const MachineBasicBlock *MBB) {
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MachineBasicBlock *T, *F;
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SmallVector<MachineOperand, 4> Cond;
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return !tii_.AnalyzeBranch(const_cast<MachineBasicBlock&>(*MBB), T, F, Cond);
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}
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/// analyzeUses - Count instructions, basic blocks, and loops using curli.
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void SplitAnalysis::analyzeUses() {
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const MachineRegisterInfo &MRI = mf_.getRegInfo();
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for (MachineRegisterInfo::reg_iterator I = MRI.reg_begin(curli_->reg);
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MachineInstr *MI = I.skipInstruction();) {
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if (MI->isDebugValue() || !usingInstrs_.insert(MI))
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continue;
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MachineBasicBlock *MBB = MI->getParent();
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if (usingBlocks_[MBB]++)
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continue;
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for (MachineLoop *Loop = loops_.getLoopFor(MBB); Loop;
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Loop = Loop->getParentLoop())
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usingLoops_[Loop]++;
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}
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DEBUG(dbgs() << " counted "
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<< usingInstrs_.size() << " instrs, "
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<< usingBlocks_.size() << " blocks, "
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<< usingLoops_.size() << " loops.\n");
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}
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void SplitAnalysis::print(const BlockPtrSet &B, raw_ostream &OS) const {
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for (BlockPtrSet::const_iterator I = B.begin(), E = B.end(); I != E; ++I) {
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unsigned count = usingBlocks_.lookup(*I);
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OS << " BB#" << (*I)->getNumber();
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if (count)
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OS << '(' << count << ')';
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}
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}
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// Get three sets of basic blocks surrounding a loop: Blocks inside the loop,
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// predecessor blocks, and exit blocks.
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void SplitAnalysis::getLoopBlocks(const MachineLoop *Loop, LoopBlocks &Blocks) {
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Blocks.clear();
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// Blocks in the loop.
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Blocks.Loop.insert(Loop->block_begin(), Loop->block_end());
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// Predecessor blocks.
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const MachineBasicBlock *Header = Loop->getHeader();
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for (MachineBasicBlock::const_pred_iterator I = Header->pred_begin(),
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E = Header->pred_end(); I != E; ++I)
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if (!Blocks.Loop.count(*I))
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Blocks.Preds.insert(*I);
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// Exit blocks.
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for (MachineLoop::block_iterator I = Loop->block_begin(),
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E = Loop->block_end(); I != E; ++I) {
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const MachineBasicBlock *MBB = *I;
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for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(),
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SE = MBB->succ_end(); SI != SE; ++SI)
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if (!Blocks.Loop.count(*SI))
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Blocks.Exits.insert(*SI);
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}
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}
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void SplitAnalysis::print(const LoopBlocks &B, raw_ostream &OS) const {
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OS << "Loop:";
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print(B.Loop, OS);
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OS << ", preds:";
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print(B.Preds, OS);
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OS << ", exits:";
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print(B.Exits, OS);
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}
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/// analyzeLoopPeripheralUse - Return an enum describing how curli_ is used in
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/// and around the Loop.
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SplitAnalysis::LoopPeripheralUse SplitAnalysis::
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analyzeLoopPeripheralUse(const SplitAnalysis::LoopBlocks &Blocks) {
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LoopPeripheralUse use = ContainedInLoop;
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for (BlockCountMap::iterator I = usingBlocks_.begin(), E = usingBlocks_.end();
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I != E; ++I) {
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const MachineBasicBlock *MBB = I->first;
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// Is this a peripheral block?
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if (use < MultiPeripheral &&
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(Blocks.Preds.count(MBB) || Blocks.Exits.count(MBB))) {
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if (I->second > 1) use = MultiPeripheral;
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else use = SinglePeripheral;
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continue;
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}
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// Is it a loop block?
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if (Blocks.Loop.count(MBB))
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continue;
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// It must be an unrelated block.
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DEBUG(dbgs() << ", outside: BB#" << MBB->getNumber());
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return OutsideLoop;
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}
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return use;
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}
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/// getCriticalExits - It may be necessary to partially break critical edges
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/// leaving the loop if an exit block has predecessors from outside the loop
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/// periphery.
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void SplitAnalysis::getCriticalExits(const SplitAnalysis::LoopBlocks &Blocks,
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BlockPtrSet &CriticalExits) {
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CriticalExits.clear();
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// A critical exit block has curli live-in, and has a predecessor that is not
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// in the loop nor a loop predecessor. For such an exit block, the edges
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// carrying the new variable must be moved to a new pre-exit block.
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for (BlockPtrSet::iterator I = Blocks.Exits.begin(), E = Blocks.Exits.end();
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I != E; ++I) {
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const MachineBasicBlock *Exit = *I;
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// A single-predecessor exit block is definitely not a critical edge.
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if (Exit->pred_size() == 1)
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continue;
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// This exit may not have curli live in at all. No need to split.
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if (!lis_.isLiveInToMBB(*curli_, Exit))
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continue;
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// Does this exit block have a predecessor that is not a loop block or loop
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// predecessor?
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for (MachineBasicBlock::const_pred_iterator PI = Exit->pred_begin(),
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PE = Exit->pred_end(); PI != PE; ++PI) {
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const MachineBasicBlock *Pred = *PI;
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if (Blocks.Loop.count(Pred) || Blocks.Preds.count(Pred))
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continue;
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// This is a critical exit block, and we need to split the exit edge.
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CriticalExits.insert(Exit);
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break;
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}
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}
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}
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void SplitAnalysis::getCriticalPreds(const SplitAnalysis::LoopBlocks &Blocks,
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BlockPtrSet &CriticalPreds) {
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CriticalPreds.clear();
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// A critical predecessor block has curli live-out, and has a successor that
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// has curli live-in and is not in the loop nor a loop exit block. For such a
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// predecessor block, we must carry the value in both the 'inside' and
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// 'outside' registers.
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for (BlockPtrSet::iterator I = Blocks.Preds.begin(), E = Blocks.Preds.end();
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I != E; ++I) {
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const MachineBasicBlock *Pred = *I;
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// Definitely not a critical edge.
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if (Pred->succ_size() == 1)
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continue;
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// This block may not have curli live out at all if there is a PHI.
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if (!lis_.isLiveOutOfMBB(*curli_, Pred))
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continue;
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// Does this block have a successor outside the loop?
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for (MachineBasicBlock::const_pred_iterator SI = Pred->succ_begin(),
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SE = Pred->succ_end(); SI != SE; ++SI) {
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const MachineBasicBlock *Succ = *SI;
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if (Blocks.Loop.count(Succ) || Blocks.Exits.count(Succ))
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continue;
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if (!lis_.isLiveInToMBB(*curli_, Succ))
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continue;
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// This is a critical predecessor block.
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CriticalPreds.insert(Pred);
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break;
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}
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}
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}
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/// canSplitCriticalExits - Return true if it is possible to insert new exit
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/// blocks before the blocks in CriticalExits.
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bool
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SplitAnalysis::canSplitCriticalExits(const SplitAnalysis::LoopBlocks &Blocks,
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BlockPtrSet &CriticalExits) {
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// If we don't allow critical edge splitting, require no critical exits.
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if (!AllowSplit)
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return CriticalExits.empty();
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for (BlockPtrSet::iterator I = CriticalExits.begin(), E = CriticalExits.end();
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I != E; ++I) {
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const MachineBasicBlock *Succ = *I;
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// We want to insert a new pre-exit MBB before Succ, and change all the
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// in-loop blocks to branch to the pre-exit instead of Succ.
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// Check that all the in-loop predecessors can be changed.
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for (MachineBasicBlock::const_pred_iterator PI = Succ->pred_begin(),
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PE = Succ->pred_end(); PI != PE; ++PI) {
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const MachineBasicBlock *Pred = *PI;
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// The external predecessors won't be altered.
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if (!Blocks.Loop.count(Pred) && !Blocks.Preds.count(Pred))
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continue;
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if (!canAnalyzeBranch(Pred))
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return false;
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}
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// If Succ's layout predecessor falls through, that too must be analyzable.
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// We need to insert the pre-exit block in the gap.
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MachineFunction::const_iterator MFI = Succ;
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if (MFI == mf_.begin())
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continue;
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if (!canAnalyzeBranch(--MFI))
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return false;
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}
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// No problems found.
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return true;
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}
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void SplitAnalysis::analyze(const LiveInterval *li) {
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clear();
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curli_ = li;
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analyzeUses();
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}
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void SplitAnalysis::getSplitLoops(LoopPtrSet &Loops) {
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assert(curli_ && "Call analyze() before getSplitLoops");
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if (usingLoops_.empty())
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return;
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LoopBlocks Blocks;
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BlockPtrSet CriticalExits;
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// We split around loops where curli is used outside the periphery.
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for (LoopCountMap::const_iterator I = usingLoops_.begin(),
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E = usingLoops_.end(); I != E; ++I) {
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const MachineLoop *Loop = I->first;
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getLoopBlocks(Loop, Blocks);
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DEBUG({ dbgs() << " "; print(Blocks, dbgs()); });
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switch(analyzeLoopPeripheralUse(Blocks)) {
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case OutsideLoop:
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break;
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case MultiPeripheral:
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// FIXME: We could split a live range with multiple uses in a peripheral
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// block and still make progress. However, it is possible that splitting
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// another live range will insert copies into a peripheral block, and
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// there is a small chance we can enter an infinite loop, inserting copies
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// forever.
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// For safety, stick to splitting live ranges with uses outside the
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// periphery.
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DEBUG(dbgs() << ": multiple peripheral uses");
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break;
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case ContainedInLoop:
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DEBUG(dbgs() << ": fully contained\n");
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continue;
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case SinglePeripheral:
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DEBUG(dbgs() << ": single peripheral use\n");
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continue;
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}
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// Will it be possible to split around this loop?
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getCriticalExits(Blocks, CriticalExits);
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DEBUG(dbgs() << ": " << CriticalExits.size() << " critical exits\n");
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if (!canSplitCriticalExits(Blocks, CriticalExits))
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continue;
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// This is a possible split.
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Loops.insert(Loop);
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}
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DEBUG(dbgs() << " getSplitLoops found " << Loops.size()
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<< " candidate loops.\n");
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}
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const MachineLoop *SplitAnalysis::getBestSplitLoop() {
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LoopPtrSet Loops;
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getSplitLoops(Loops);
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if (Loops.empty())
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return 0;
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// Pick the earliest loop.
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// FIXME: Are there other heuristics to consider?
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const MachineLoop *Best = 0;
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SlotIndex BestIdx;
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for (LoopPtrSet::const_iterator I = Loops.begin(), E = Loops.end(); I != E;
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++I) {
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SlotIndex Idx = lis_.getMBBStartIdx((*I)->getHeader());
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if (!Best || Idx < BestIdx)
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Best = *I, BestIdx = Idx;
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}
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DEBUG(dbgs() << " getBestSplitLoop found " << *Best);
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return Best;
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}
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/// isBypassLoop - Return true if curli is live through Loop and has no uses
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/// inside the loop. Bypass loops are candidates for splitting because it can
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/// prevent interference inside the loop.
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bool SplitAnalysis::isBypassLoop(const MachineLoop *Loop) {
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// If curli is live into the loop header and there are no uses in the loop, it
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// must be live in the entire loop and live on at least one exiting edge.
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return !usingLoops_.count(Loop) &&
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lis_.isLiveInToMBB(*curli_, Loop->getHeader());
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}
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/// getBypassLoops - Get all the maximal bypass loops. These are the bypass
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/// loops whose parent is not a bypass loop.
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void SplitAnalysis::getBypassLoops(LoopPtrSet &BypassLoops) {
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SmallVector<MachineLoop*, 8> Todo(loops_.begin(), loops_.end());
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while (!Todo.empty()) {
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MachineLoop *Loop = Todo.pop_back_val();
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if (!usingLoops_.count(Loop)) {
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// This is either a bypass loop or completely irrelevant.
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if (lis_.isLiveInToMBB(*curli_, Loop->getHeader()))
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BypassLoops.insert(Loop);
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// Either way, skip the child loops.
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continue;
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}
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// The child loops may be bypass loops.
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Todo.append(Loop->begin(), Loop->end());
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}
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}
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//===----------------------------------------------------------------------===//
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// LiveIntervalMap
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//===----------------------------------------------------------------------===//
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// Work around the fact that the std::pair constructors are broken for pointer
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// pairs in some implementations. makeVV(x, 0) works.
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static inline std::pair<const VNInfo*, VNInfo*>
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makeVV(const VNInfo *a, VNInfo *b) {
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return std::make_pair(a, b);
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}
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void LiveIntervalMap::reset(LiveInterval *li) {
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li_ = li;
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valueMap_.clear();
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liveOutCache_.clear();
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}
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bool LiveIntervalMap::isComplexMapped(const VNInfo *ParentVNI) const {
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ValueMap::const_iterator i = valueMap_.find(ParentVNI);
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return i != valueMap_.end() && i->second == 0;
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}
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// defValue - Introduce a li_ def for ParentVNI that could be later than
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// ParentVNI->def.
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VNInfo *LiveIntervalMap::defValue(const VNInfo *ParentVNI, SlotIndex Idx) {
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assert(li_ && "call reset first");
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assert(ParentVNI && "Mapping NULL value");
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assert(Idx.isValid() && "Invalid SlotIndex");
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assert(parentli_.getVNInfoAt(Idx) == ParentVNI && "Bad ParentVNI");
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// Create a new value.
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VNInfo *VNI = li_->getNextValue(Idx, 0, lis_.getVNInfoAllocator());
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// Preserve the PHIDef bit.
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if (ParentVNI->isPHIDef() && Idx == ParentVNI->def)
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VNI->setIsPHIDef(true);
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// Use insert for lookup, so we can add missing values with a second lookup.
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std::pair<ValueMap::iterator,bool> InsP =
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valueMap_.insert(makeVV(ParentVNI, Idx == ParentVNI->def ? VNI : 0));
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// This is now a complex def. Mark with a NULL in valueMap.
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if (!InsP.second)
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InsP.first->second = 0;
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return VNI;
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}
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// mapValue - Find the mapped value for ParentVNI at Idx.
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// Potentially create phi-def values.
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VNInfo *LiveIntervalMap::mapValue(const VNInfo *ParentVNI, SlotIndex Idx,
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bool *simple) {
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assert(li_ && "call reset first");
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assert(ParentVNI && "Mapping NULL value");
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assert(Idx.isValid() && "Invalid SlotIndex");
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assert(parentli_.getVNInfoAt(Idx) == ParentVNI && "Bad ParentVNI");
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// Use insert for lookup, so we can add missing values with a second lookup.
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std::pair<ValueMap::iterator,bool> InsP =
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valueMap_.insert(makeVV(ParentVNI, 0));
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// This was an unknown value. Create a simple mapping.
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if (InsP.second) {
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if (simple) *simple = true;
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return InsP.first->second = li_->createValueCopy(ParentVNI,
|
|
lis_.getVNInfoAllocator());
|
|
}
|
|
|
|
// This was a simple mapped value.
|
|
if (InsP.first->second) {
|
|
if (simple) *simple = true;
|
|
return InsP.first->second;
|
|
}
|
|
|
|
// This is a complex mapped value. There may be multiple defs, and we may need
|
|
// to create phi-defs.
|
|
if (simple) *simple = false;
|
|
MachineBasicBlock *IdxMBB = lis_.getMBBFromIndex(Idx);
|
|
assert(IdxMBB && "No MBB at Idx");
|
|
|
|
// Is there a def in the same MBB we can extend?
|
|
if (VNInfo *VNI = extendTo(IdxMBB, Idx))
|
|
return VNI;
|
|
|
|
// Now for the fun part. We know that ParentVNI potentially has multiple defs,
|
|
// and we may need to create even more phi-defs to preserve VNInfo SSA form.
|
|
// Perform a search for all predecessor blocks where we know the dominating
|
|
// VNInfo. Insert phi-def VNInfos along the path back to IdxMBB.
|
|
DEBUG(dbgs() << "\n Reaching defs for BB#" << IdxMBB->getNumber()
|
|
<< " at " << Idx << " in " << *li_ << '\n');
|
|
|
|
// Blocks where li_ should be live-in.
|
|
SmallVector<MachineDomTreeNode*, 16> LiveIn;
|
|
LiveIn.push_back(mdt_[IdxMBB]);
|
|
|
|
// Using liveOutCache_ as a visited set, perform a BFS for all reaching defs.
|
|
for (unsigned i = 0; i != LiveIn.size(); ++i) {
|
|
MachineBasicBlock *MBB = LiveIn[i]->getBlock();
|
|
for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
|
|
PE = MBB->pred_end(); PI != PE; ++PI) {
|
|
MachineBasicBlock *Pred = *PI;
|
|
// Is this a known live-out block?
|
|
std::pair<LiveOutMap::iterator,bool> LOIP =
|
|
liveOutCache_.insert(std::make_pair(Pred, LiveOutPair()));
|
|
// Yes, we have been here before.
|
|
if (!LOIP.second) {
|
|
DEBUG(if (VNInfo *VNI = LOIP.first->second.first)
|
|
dbgs() << " known valno #" << VNI->id
|
|
<< " at BB#" << Pred->getNumber() << '\n');
|
|
continue;
|
|
}
|
|
|
|
// Does Pred provide a live-out value?
|
|
SlotIndex Last = lis_.getMBBEndIdx(Pred).getPrevSlot();
|
|
if (VNInfo *VNI = extendTo(Pred, Last)) {
|
|
MachineBasicBlock *DefMBB = lis_.getMBBFromIndex(VNI->def);
|
|
DEBUG(dbgs() << " found valno #" << VNI->id
|
|
<< " from BB#" << DefMBB->getNumber()
|
|
<< " at BB#" << Pred->getNumber() << '\n');
|
|
LiveOutPair &LOP = LOIP.first->second;
|
|
LOP.first = VNI;
|
|
LOP.second = mdt_[DefMBB];
|
|
continue;
|
|
}
|
|
// No, we need a live-in value for Pred as well
|
|
if (Pred != IdxMBB)
|
|
LiveIn.push_back(mdt_[Pred]);
|
|
}
|
|
}
|
|
|
|
// We may need to add phi-def values to preserve the SSA form.
|
|
// This is essentially the same iterative algorithm that SSAUpdater uses,
|
|
// except we already have a dominator tree, so we don't have to recompute it.
|
|
VNInfo *IdxVNI = 0;
|
|
unsigned Changes;
|
|
do {
|
|
Changes = 0;
|
|
DEBUG(dbgs() << " Iterating over " << LiveIn.size() << " blocks.\n");
|
|
// Propagate live-out values down the dominator tree, inserting phi-defs when
|
|
// necessary. Since LiveIn was created by a BFS, going backwards makes it more
|
|
// likely for us to visit immediate dominators before their children.
|
|
for (unsigned i = LiveIn.size(); i; --i) {
|
|
MachineDomTreeNode *Node = LiveIn[i-1];
|
|
MachineBasicBlock *MBB = Node->getBlock();
|
|
MachineDomTreeNode *IDom = Node->getIDom();
|
|
LiveOutPair IDomValue;
|
|
// We need a live-in value to a block with no immediate dominator?
|
|
// This is probably an unreachable block that has survived somehow.
|
|
bool needPHI = !IDom;
|
|
|
|
// Get the IDom live-out value.
|
|
if (!needPHI) {
|
|
LiveOutMap::iterator I = liveOutCache_.find(IDom->getBlock());
|
|
if (I != liveOutCache_.end())
|
|
IDomValue = I->second;
|
|
else
|
|
// If IDom is outside our set of live-out blocks, there must be new
|
|
// defs, and we need a phi-def here.
|
|
needPHI = true;
|
|
}
|
|
|
|
// IDom dominates all of our predecessors, but it may not be the immediate
|
|
// dominator. Check if any of them have live-out values that are properly
|
|
// dominated by IDom. If so, we need a phi-def here.
|
|
if (!needPHI) {
|
|
for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
|
|
PE = MBB->pred_end(); PI != PE; ++PI) {
|
|
LiveOutPair Value = liveOutCache_[*PI];
|
|
if (!Value.first || Value.first == IDomValue.first)
|
|
continue;
|
|
// This predecessor is carrying something other than IDomValue.
|
|
// It could be because IDomValue hasn't propagated yet, or it could be
|
|
// because MBB is in the dominance frontier of that value.
|
|
if (mdt_.dominates(IDom, Value.second)) {
|
|
needPHI = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Create a phi-def if required.
|
|
if (needPHI) {
|
|
++Changes;
|
|
SlotIndex Start = lis_.getMBBStartIdx(MBB);
|
|
VNInfo *VNI = li_->getNextValue(Start, 0, lis_.getVNInfoAllocator());
|
|
VNI->setIsPHIDef(true);
|
|
DEBUG(dbgs() << " - BB#" << MBB->getNumber()
|
|
<< " phi-def #" << VNI->id << " at " << Start << '\n');
|
|
// We no longer need li_ to be live-in.
|
|
LiveIn.erase(LiveIn.begin()+(i-1));
|
|
// Blocks in LiveIn are either IdxMBB, or have a value live-through.
|
|
if (MBB == IdxMBB)
|
|
IdxVNI = VNI;
|
|
// Check if we need to update live-out info.
|
|
LiveOutMap::iterator I = liveOutCache_.find(MBB);
|
|
if (I == liveOutCache_.end() || I->second.second == Node) {
|
|
// We already have a live-out defined in MBB, so this must be IdxMBB.
|
|
assert(MBB == IdxMBB && "Adding phi-def to known live-out");
|
|
li_->addRange(LiveRange(Start, Idx.getNextSlot(), VNI));
|
|
} else {
|
|
// This phi-def is also live-out, so color the whole block.
|
|
li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI));
|
|
I->second = LiveOutPair(VNI, Node);
|
|
}
|
|
} else if (IDomValue.first) {
|
|
// No phi-def here. Remember incoming value for IdxMBB.
|
|
if (MBB == IdxMBB)
|
|
IdxVNI = IDomValue.first;
|
|
// Propagate IDomValue if needed:
|
|
// MBB is live-out and doesn't define its own value.
|
|
LiveOutMap::iterator I = liveOutCache_.find(MBB);
|
|
if (I != liveOutCache_.end() && I->second.second != Node &&
|
|
I->second.first != IDomValue.first) {
|
|
++Changes;
|
|
I->second = IDomValue;
|
|
DEBUG(dbgs() << " - BB#" << MBB->getNumber()
|
|
<< " idom valno #" << IDomValue.first->id
|
|
<< " from BB#" << IDom->getBlock()->getNumber() << '\n');
|
|
}
|
|
}
|
|
}
|
|
DEBUG(dbgs() << " - made " << Changes << " changes.\n");
|
|
} while (Changes);
|
|
|
|
assert(IdxVNI && "Didn't find value for Idx");
|
|
|
|
#ifndef NDEBUG
|
|
// Check the liveOutCache_ invariants.
|
|
for (LiveOutMap::iterator I = liveOutCache_.begin(), E = liveOutCache_.end();
|
|
I != E; ++I) {
|
|
assert(I->first && "Null MBB entry in cache");
|
|
assert(I->second.first && "Null VNInfo in cache");
|
|
assert(I->second.second && "Null DomTreeNode in cache");
|
|
if (I->second.second->getBlock() == I->first)
|
|
continue;
|
|
for (MachineBasicBlock::pred_iterator PI = I->first->pred_begin(),
|
|
PE = I->first->pred_end(); PI != PE; ++PI)
|
|
assert(liveOutCache_.lookup(*PI) == I->second && "Bad invariant");
|
|
}
|
|
#endif
|
|
|
|
// Since we went through the trouble of a full BFS visiting all reaching defs,
|
|
// the values in LiveIn are now accurate. No more phi-defs are needed
|
|
// for these blocks, so we can color the live ranges.
|
|
// This makes the next mapValue call much faster.
|
|
for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) {
|
|
MachineBasicBlock *MBB = LiveIn[i]->getBlock();
|
|
SlotIndex Start = lis_.getMBBStartIdx(MBB);
|
|
if (MBB == IdxMBB) {
|
|
li_->addRange(LiveRange(Start, Idx.getNextSlot(), IdxVNI));
|
|
continue;
|
|
}
|
|
// Anything in LiveIn other than IdxMBB is live-through.
|
|
VNInfo *VNI = liveOutCache_.lookup(MBB).first;
|
|
assert(VNI && "Missing block value");
|
|
li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI));
|
|
}
|
|
|
|
return IdxVNI;
|
|
}
|
|
|
|
// extendTo - Find the last li_ value defined in MBB at or before Idx. The
|
|
// parentli_ is assumed to be live at Idx. Extend the live range to Idx.
|
|
// Return the found VNInfo, or NULL.
|
|
VNInfo *LiveIntervalMap::extendTo(const MachineBasicBlock *MBB, SlotIndex Idx) {
|
|
assert(li_ && "call reset first");
|
|
LiveInterval::iterator I = std::upper_bound(li_->begin(), li_->end(), Idx);
|
|
if (I == li_->begin())
|
|
return 0;
|
|
--I;
|
|
if (I->end <= lis_.getMBBStartIdx(MBB))
|
|
return 0;
|
|
if (I->end <= Idx)
|
|
I->end = Idx.getNextSlot();
|
|
return I->valno;
|
|
}
|
|
|
|
// addSimpleRange - Add a simple range from parentli_ to li_.
|
|
// ParentVNI must be live in the [Start;End) interval.
|
|
void LiveIntervalMap::addSimpleRange(SlotIndex Start, SlotIndex End,
|
|
const VNInfo *ParentVNI) {
|
|
assert(li_ && "call reset first");
|
|
bool simple;
|
|
VNInfo *VNI = mapValue(ParentVNI, Start, &simple);
|
|
// A simple mapping is easy.
|
|
if (simple) {
|
|
li_->addRange(LiveRange(Start, End, VNI));
|
|
return;
|
|
}
|
|
|
|
// ParentVNI is a complex value. We must map per MBB.
|
|
MachineFunction::iterator MBB = lis_.getMBBFromIndex(Start);
|
|
MachineFunction::iterator MBBE = lis_.getMBBFromIndex(End.getPrevSlot());
|
|
|
|
if (MBB == MBBE) {
|
|
li_->addRange(LiveRange(Start, End, VNI));
|
|
return;
|
|
}
|
|
|
|
// First block.
|
|
li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB), VNI));
|
|
|
|
// Run sequence of full blocks.
|
|
for (++MBB; MBB != MBBE; ++MBB) {
|
|
Start = lis_.getMBBStartIdx(MBB);
|
|
li_->addRange(LiveRange(Start, lis_.getMBBEndIdx(MBB),
|
|
mapValue(ParentVNI, Start)));
|
|
}
|
|
|
|
// Final block.
|
|
Start = lis_.getMBBStartIdx(MBB);
|
|
if (Start != End)
|
|
li_->addRange(LiveRange(Start, End, mapValue(ParentVNI, Start)));
|
|
}
|
|
|
|
/// addRange - Add live ranges to li_ where [Start;End) intersects parentli_.
|
|
/// All needed values whose def is not inside [Start;End) must be defined
|
|
/// beforehand so mapValue will work.
|
|
void LiveIntervalMap::addRange(SlotIndex Start, SlotIndex End) {
|
|
assert(li_ && "call reset first");
|
|
LiveInterval::const_iterator B = parentli_.begin(), E = parentli_.end();
|
|
LiveInterval::const_iterator I = std::lower_bound(B, E, Start);
|
|
|
|
// Check if --I begins before Start and overlaps.
|
|
if (I != B) {
|
|
--I;
|
|
if (I->end > Start)
|
|
addSimpleRange(Start, std::min(End, I->end), I->valno);
|
|
++I;
|
|
}
|
|
|
|
// The remaining ranges begin after Start.
|
|
for (;I != E && I->start < End; ++I)
|
|
addSimpleRange(I->start, std::min(End, I->end), I->valno);
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Split Editor
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
/// Create a new SplitEditor for editing the LiveInterval analyzed by SA.
|
|
SplitEditor::SplitEditor(SplitAnalysis &sa,
|
|
LiveIntervals &lis,
|
|
VirtRegMap &vrm,
|
|
MachineDominatorTree &mdt,
|
|
LiveRangeEdit &edit)
|
|
: sa_(sa), lis_(lis), vrm_(vrm),
|
|
mri_(vrm.getMachineFunction().getRegInfo()),
|
|
tii_(*vrm.getMachineFunction().getTarget().getInstrInfo()),
|
|
tri_(*vrm.getMachineFunction().getTarget().getRegisterInfo()),
|
|
edit_(edit),
|
|
dupli_(lis_, mdt, edit.getParent()),
|
|
openli_(lis_, mdt, edit.getParent())
|
|
{
|
|
// We don't need an AliasAnalysis since we will only be performing
|
|
// cheap-as-a-copy remats anyway.
|
|
edit_.anyRematerializable(lis_, tii_, 0);
|
|
}
|
|
|
|
bool SplitEditor::intervalsLiveAt(SlotIndex Idx) const {
|
|
for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I)
|
|
if (*I != dupli_.getLI() && (*I)->liveAt(Idx))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
VNInfo *SplitEditor::defFromParent(LiveIntervalMap &Reg,
|
|
VNInfo *ParentVNI,
|
|
SlotIndex UseIdx,
|
|
MachineBasicBlock &MBB,
|
|
MachineBasicBlock::iterator I) {
|
|
VNInfo *VNI = 0;
|
|
MachineInstr *CopyMI = 0;
|
|
SlotIndex Def;
|
|
|
|
// Attempt cheap-as-a-copy rematerialization.
|
|
LiveRangeEdit::Remat RM(ParentVNI);
|
|
if (edit_.canRematerializeAt(RM, UseIdx, true, lis_)) {
|
|
Def = edit_.rematerializeAt(MBB, I, Reg.getLI()->reg, RM,
|
|
lis_, tii_, tri_);
|
|
} else {
|
|
// Can't remat, just insert a copy from parent.
|
|
CopyMI = BuildMI(MBB, I, DebugLoc(), tii_.get(TargetOpcode::COPY),
|
|
Reg.getLI()->reg).addReg(edit_.getReg());
|
|
Def = lis_.InsertMachineInstrInMaps(CopyMI).getDefIndex();
|
|
}
|
|
|
|
// Define the value in Reg.
|
|
VNI = Reg.defValue(ParentVNI, Def);
|
|
VNI->setCopy(CopyMI);
|
|
|
|
// Add minimal liveness for the new value.
|
|
if (UseIdx < Def)
|
|
UseIdx = Def;
|
|
Reg.getLI()->addRange(LiveRange(Def, UseIdx.getNextSlot(), VNI));
|
|
return VNI;
|
|
}
|
|
|
|
/// Create a new virtual register and live interval.
|
|
void SplitEditor::openIntv() {
|
|
assert(!openli_.getLI() && "Previous LI not closed before openIntv");
|
|
if (!dupli_.getLI())
|
|
dupli_.reset(&edit_.create(mri_, lis_, vrm_));
|
|
|
|
openli_.reset(&edit_.create(mri_, lis_, vrm_));
|
|
}
|
|
|
|
/// enterIntvBefore - Enter openli before the instruction at Idx. If curli is
|
|
/// not live before Idx, a COPY is not inserted.
|
|
void SplitEditor::enterIntvBefore(SlotIndex Idx) {
|
|
assert(openli_.getLI() && "openIntv not called before enterIntvBefore");
|
|
Idx = Idx.getUseIndex();
|
|
DEBUG(dbgs() << " enterIntvBefore " << Idx);
|
|
VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Idx);
|
|
if (!ParentVNI) {
|
|
DEBUG(dbgs() << ": not live\n");
|
|
return;
|
|
}
|
|
DEBUG(dbgs() << ": valno " << ParentVNI->id);
|
|
truncatedValues.insert(ParentVNI);
|
|
MachineInstr *MI = lis_.getInstructionFromIndex(Idx);
|
|
assert(MI && "enterIntvBefore called with invalid index");
|
|
|
|
defFromParent(openli_, ParentVNI, Idx, *MI->getParent(), MI);
|
|
|
|
DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
|
|
}
|
|
|
|
/// enterIntvAtEnd - Enter openli at the end of MBB.
|
|
void SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) {
|
|
assert(openli_.getLI() && "openIntv not called before enterIntvAtEnd");
|
|
SlotIndex End = lis_.getMBBEndIdx(&MBB).getPrevSlot();
|
|
DEBUG(dbgs() << " enterIntvAtEnd BB#" << MBB.getNumber() << ", " << End);
|
|
VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(End);
|
|
if (!ParentVNI) {
|
|
DEBUG(dbgs() << ": not live\n");
|
|
return;
|
|
}
|
|
DEBUG(dbgs() << ": valno " << ParentVNI->id);
|
|
truncatedValues.insert(ParentVNI);
|
|
defFromParent(openli_, ParentVNI, End, MBB, MBB.getFirstTerminator());
|
|
DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
|
|
}
|
|
|
|
/// useIntv - indicate that all instructions in MBB should use openli.
|
|
void SplitEditor::useIntv(const MachineBasicBlock &MBB) {
|
|
useIntv(lis_.getMBBStartIdx(&MBB), lis_.getMBBEndIdx(&MBB));
|
|
}
|
|
|
|
void SplitEditor::useIntv(SlotIndex Start, SlotIndex End) {
|
|
assert(openli_.getLI() && "openIntv not called before useIntv");
|
|
openli_.addRange(Start, End);
|
|
DEBUG(dbgs() << " use [" << Start << ';' << End << "): "
|
|
<< *openli_.getLI() << '\n');
|
|
}
|
|
|
|
/// leaveIntvAfter - Leave openli after the instruction at Idx.
|
|
void SplitEditor::leaveIntvAfter(SlotIndex Idx) {
|
|
assert(openli_.getLI() && "openIntv not called before leaveIntvAfter");
|
|
DEBUG(dbgs() << " leaveIntvAfter " << Idx);
|
|
|
|
// The interval must be live beyond the instruction at Idx.
|
|
Idx = Idx.getBoundaryIndex();
|
|
VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Idx);
|
|
if (!ParentVNI) {
|
|
DEBUG(dbgs() << ": not live\n");
|
|
return;
|
|
}
|
|
DEBUG(dbgs() << ": valno " << ParentVNI->id);
|
|
|
|
MachineBasicBlock::iterator MII = lis_.getInstructionFromIndex(Idx);
|
|
VNInfo *VNI = defFromParent(dupli_, ParentVNI, Idx,
|
|
*MII->getParent(), llvm::next(MII));
|
|
|
|
// Make sure that openli is properly extended from Idx to the new copy.
|
|
// FIXME: This shouldn't be necessary for remats.
|
|
openli_.addSimpleRange(Idx, VNI->def, ParentVNI);
|
|
|
|
DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
|
|
}
|
|
|
|
/// leaveIntvAtTop - Leave the interval at the top of MBB.
|
|
/// Currently, only one value can leave the interval.
|
|
void SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) {
|
|
assert(openli_.getLI() && "openIntv not called before leaveIntvAtTop");
|
|
SlotIndex Start = lis_.getMBBStartIdx(&MBB);
|
|
DEBUG(dbgs() << " leaveIntvAtTop BB#" << MBB.getNumber() << ", " << Start);
|
|
|
|
VNInfo *ParentVNI = edit_.getParent().getVNInfoAt(Start);
|
|
if (!ParentVNI) {
|
|
DEBUG(dbgs() << ": not live\n");
|
|
return;
|
|
}
|
|
|
|
VNInfo *VNI = defFromParent(dupli_, ParentVNI, Start, MBB,
|
|
MBB.SkipPHIsAndLabels(MBB.begin()));
|
|
|
|
// Finally we must make sure that openli is properly extended from Start to
|
|
// the new copy.
|
|
openli_.addSimpleRange(Start, VNI->def, ParentVNI);
|
|
DEBUG(dbgs() << ": " << *openli_.getLI() << '\n');
|
|
}
|
|
|
|
/// closeIntv - Indicate that we are done editing the currently open
|
|
/// LiveInterval, and ranges can be trimmed.
|
|
void SplitEditor::closeIntv() {
|
|
assert(openli_.getLI() && "openIntv not called before closeIntv");
|
|
|
|
DEBUG(dbgs() << " closeIntv cleaning up\n");
|
|
DEBUG(dbgs() << " open " << *openli_.getLI() << '\n');
|
|
openli_.reset(0);
|
|
}
|
|
|
|
/// rewrite - Rewrite all uses of reg to use the new registers.
|
|
void SplitEditor::rewrite(unsigned reg) {
|
|
for (MachineRegisterInfo::reg_iterator RI = mri_.reg_begin(reg),
|
|
RE = mri_.reg_end(); RI != RE;) {
|
|
MachineOperand &MO = RI.getOperand();
|
|
unsigned OpNum = RI.getOperandNo();
|
|
MachineInstr *MI = MO.getParent();
|
|
++RI;
|
|
if (MI->isDebugValue()) {
|
|
DEBUG(dbgs() << "Zapping " << *MI);
|
|
// FIXME: We can do much better with debug values.
|
|
MO.setReg(0);
|
|
continue;
|
|
}
|
|
SlotIndex Idx = lis_.getInstructionIndex(MI);
|
|
Idx = MO.isUse() ? Idx.getUseIndex() : Idx.getDefIndex();
|
|
LiveInterval *LI = 0;
|
|
for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E;
|
|
++I) {
|
|
LiveInterval *testli = *I;
|
|
if (testli->liveAt(Idx)) {
|
|
LI = testli;
|
|
break;
|
|
}
|
|
}
|
|
DEBUG(dbgs() << " rewr BB#" << MI->getParent()->getNumber() << '\t'<< Idx);
|
|
assert(LI && "No register was live at use");
|
|
MO.setReg(LI->reg);
|
|
if (MO.isUse() && !MI->isRegTiedToDefOperand(OpNum))
|
|
MO.setIsKill(LI->killedAt(Idx.getDefIndex()));
|
|
DEBUG(dbgs() << '\t' << *MI);
|
|
}
|
|
}
|
|
|
|
void
|
|
SplitEditor::addTruncSimpleRange(SlotIndex Start, SlotIndex End, VNInfo *VNI) {
|
|
// Build vector of iterator pairs from the intervals.
|
|
typedef std::pair<LiveInterval::const_iterator,
|
|
LiveInterval::const_iterator> IIPair;
|
|
SmallVector<IIPair, 8> Iters;
|
|
for (LiveRangeEdit::iterator LI = edit_.begin(), LE = edit_.end(); LI != LE;
|
|
++LI) {
|
|
if (*LI == dupli_.getLI())
|
|
continue;
|
|
LiveInterval::const_iterator I = (*LI)->find(Start);
|
|
LiveInterval::const_iterator E = (*LI)->end();
|
|
if (I != E)
|
|
Iters.push_back(std::make_pair(I, E));
|
|
}
|
|
|
|
SlotIndex sidx = Start;
|
|
// Break [Start;End) into segments that don't overlap any intervals.
|
|
for (;;) {
|
|
SlotIndex next = sidx, eidx = End;
|
|
// Find overlapping intervals.
|
|
for (unsigned i = 0; i != Iters.size() && sidx < eidx; ++i) {
|
|
LiveInterval::const_iterator I = Iters[i].first;
|
|
// Interval I is overlapping [sidx;eidx). Trim sidx.
|
|
if (I->start <= sidx) {
|
|
sidx = I->end;
|
|
// Move to the next run, remove iters when all are consumed.
|
|
I = ++Iters[i].first;
|
|
if (I == Iters[i].second) {
|
|
Iters.erase(Iters.begin() + i);
|
|
--i;
|
|
continue;
|
|
}
|
|
}
|
|
// Trim eidx too if needed.
|
|
if (I->start >= eidx)
|
|
continue;
|
|
eidx = I->start;
|
|
next = I->end;
|
|
}
|
|
// Now, [sidx;eidx) doesn't overlap anything in intervals_.
|
|
if (sidx < eidx)
|
|
dupli_.addSimpleRange(sidx, eidx, VNI);
|
|
// If the interval end was truncated, we can try again from next.
|
|
if (next <= sidx)
|
|
break;
|
|
sidx = next;
|
|
}
|
|
}
|
|
|
|
void SplitEditor::computeRemainder() {
|
|
// First we need to fill in the live ranges in dupli.
|
|
// If values were redefined, we need a full recoloring with SSA update.
|
|
// If values were truncated, we only need to truncate the ranges.
|
|
// If values were partially rematted, we should shrink to uses.
|
|
// If values were fully rematted, they should be omitted.
|
|
// FIXME: If a single value is redefined, just move the def and truncate.
|
|
LiveInterval &parent = edit_.getParent();
|
|
|
|
// Values that are fully contained in the split intervals.
|
|
SmallPtrSet<const VNInfo*, 8> deadValues;
|
|
// Map all curli values that should have live defs in dupli.
|
|
for (LiveInterval::const_vni_iterator I = parent.vni_begin(),
|
|
E = parent.vni_end(); I != E; ++I) {
|
|
const VNInfo *VNI = *I;
|
|
// Don't transfer unused values to the new intervals.
|
|
if (VNI->isUnused())
|
|
continue;
|
|
// Original def is contained in the split intervals.
|
|
if (intervalsLiveAt(VNI->def)) {
|
|
// Did this value escape?
|
|
if (dupli_.isMapped(VNI))
|
|
truncatedValues.insert(VNI);
|
|
else
|
|
deadValues.insert(VNI);
|
|
continue;
|
|
}
|
|
// Add minimal live range at the definition.
|
|
VNInfo *DVNI = dupli_.defValue(VNI, VNI->def);
|
|
dupli_.getLI()->addRange(LiveRange(VNI->def, VNI->def.getNextSlot(), DVNI));
|
|
}
|
|
|
|
// Add all ranges to dupli.
|
|
for (LiveInterval::const_iterator I = parent.begin(), E = parent.end();
|
|
I != E; ++I) {
|
|
const LiveRange &LR = *I;
|
|
if (truncatedValues.count(LR.valno)) {
|
|
// recolor after removing intervals_.
|
|
addTruncSimpleRange(LR.start, LR.end, LR.valno);
|
|
} else if (!deadValues.count(LR.valno)) {
|
|
// recolor without truncation.
|
|
dupli_.addSimpleRange(LR.start, LR.end, LR.valno);
|
|
}
|
|
}
|
|
|
|
// Extend dupli_ to be live out of any critical loop predecessors.
|
|
// This means we have multiple registers live out of those blocks.
|
|
// The alternative would be to split the critical edges.
|
|
if (criticalPreds_.empty())
|
|
return;
|
|
for (SplitAnalysis::BlockPtrSet::iterator I = criticalPreds_.begin(),
|
|
E = criticalPreds_.end(); I != E; ++I)
|
|
dupli_.extendTo(*I, lis_.getMBBEndIdx(*I).getPrevSlot());
|
|
criticalPreds_.clear();
|
|
}
|
|
|
|
void SplitEditor::finish() {
|
|
assert(!openli_.getLI() && "Previous LI not closed before rewrite");
|
|
assert(dupli_.getLI() && "No dupli for rewrite. Noop spilt?");
|
|
|
|
// Complete dupli liveness.
|
|
computeRemainder();
|
|
|
|
// Get rid of unused values and set phi-kill flags.
|
|
for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I)
|
|
(*I)->RenumberValues(lis_);
|
|
|
|
// Rewrite instructions.
|
|
rewrite(edit_.getReg());
|
|
|
|
// Now check if any registers were separated into multiple components.
|
|
ConnectedVNInfoEqClasses ConEQ(lis_);
|
|
for (unsigned i = 0, e = edit_.size(); i != e; ++i) {
|
|
// Don't use iterators, they are invalidated by create() below.
|
|
LiveInterval *li = edit_.get(i);
|
|
unsigned NumComp = ConEQ.Classify(li);
|
|
if (NumComp <= 1)
|
|
continue;
|
|
DEBUG(dbgs() << " " << NumComp << " components: " << *li << '\n');
|
|
SmallVector<LiveInterval*, 8> dups;
|
|
dups.push_back(li);
|
|
for (unsigned i = 1; i != NumComp; ++i)
|
|
dups.push_back(&edit_.create(mri_, lis_, vrm_));
|
|
ConEQ.Distribute(&dups[0]);
|
|
// Rewrite uses to the new regs.
|
|
rewrite(li->reg);
|
|
}
|
|
|
|
// Calculate spill weight and allocation hints for new intervals.
|
|
VirtRegAuxInfo vrai(vrm_.getMachineFunction(), lis_, sa_.loops_);
|
|
for (LiveRangeEdit::iterator I = edit_.begin(), E = edit_.end(); I != E; ++I){
|
|
LiveInterval &li = **I;
|
|
vrai.CalculateRegClass(li.reg);
|
|
vrai.CalculateWeightAndHint(li);
|
|
DEBUG(dbgs() << " new interval " << mri_.getRegClass(li.reg)->getName()
|
|
<< ":" << li << '\n');
|
|
}
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Loop Splitting
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
void SplitEditor::splitAroundLoop(const MachineLoop *Loop) {
|
|
SplitAnalysis::LoopBlocks Blocks;
|
|
sa_.getLoopBlocks(Loop, Blocks);
|
|
|
|
DEBUG({
|
|
dbgs() << " splitAround"; sa_.print(Blocks, dbgs()); dbgs() << '\n';
|
|
});
|
|
|
|
// Break critical edges as needed.
|
|
SplitAnalysis::BlockPtrSet CriticalExits;
|
|
sa_.getCriticalExits(Blocks, CriticalExits);
|
|
assert(CriticalExits.empty() && "Cannot break critical exits yet");
|
|
|
|
// Get critical predecessors so computeRemainder can deal with them.
|
|
sa_.getCriticalPreds(Blocks, criticalPreds_);
|
|
|
|
// Create new live interval for the loop.
|
|
openIntv();
|
|
|
|
// Insert copies in the predecessors if live-in to the header.
|
|
if (lis_.isLiveInToMBB(edit_.getParent(), Loop->getHeader())) {
|
|
for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Preds.begin(),
|
|
E = Blocks.Preds.end(); I != E; ++I) {
|
|
MachineBasicBlock &MBB = const_cast<MachineBasicBlock&>(**I);
|
|
enterIntvAtEnd(MBB);
|
|
}
|
|
}
|
|
|
|
// Switch all loop blocks.
|
|
for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Loop.begin(),
|
|
E = Blocks.Loop.end(); I != E; ++I)
|
|
useIntv(**I);
|
|
|
|
// Insert back copies in the exit blocks.
|
|
for (SplitAnalysis::BlockPtrSet::iterator I = Blocks.Exits.begin(),
|
|
E = Blocks.Exits.end(); I != E; ++I) {
|
|
MachineBasicBlock &MBB = const_cast<MachineBasicBlock&>(**I);
|
|
leaveIntvAtTop(MBB);
|
|
}
|
|
|
|
// Done.
|
|
closeIntv();
|
|
finish();
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Single Block Splitting
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
/// getMultiUseBlocks - if curli has more than one use in a basic block, it
|
|
/// may be an advantage to split curli for the duration of the block.
|
|
bool SplitAnalysis::getMultiUseBlocks(BlockPtrSet &Blocks) {
|
|
// If curli is local to one block, there is no point to splitting it.
|
|
if (usingBlocks_.size() <= 1)
|
|
return false;
|
|
// Add blocks with multiple uses.
|
|
for (BlockCountMap::iterator I = usingBlocks_.begin(), E = usingBlocks_.end();
|
|
I != E; ++I)
|
|
switch (I->second) {
|
|
case 0:
|
|
case 1:
|
|
continue;
|
|
case 2: {
|
|
// When there are only two uses and curli is both live in and live out,
|
|
// we don't really win anything by isolating the block since we would be
|
|
// inserting two copies.
|
|
// The remaing register would still have two uses in the block. (Unless it
|
|
// separates into disconnected components).
|
|
if (lis_.isLiveInToMBB(*curli_, I->first) &&
|
|
lis_.isLiveOutOfMBB(*curli_, I->first))
|
|
continue;
|
|
} // Fall through.
|
|
default:
|
|
Blocks.insert(I->first);
|
|
}
|
|
return !Blocks.empty();
|
|
}
|
|
|
|
/// splitSingleBlocks - Split curli into a separate live interval inside each
|
|
/// basic block in Blocks.
|
|
void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) {
|
|
DEBUG(dbgs() << " splitSingleBlocks for " << Blocks.size() << " blocks.\n");
|
|
// Determine the first and last instruction using curli in each block.
|
|
typedef std::pair<SlotIndex,SlotIndex> IndexPair;
|
|
typedef DenseMap<const MachineBasicBlock*,IndexPair> IndexPairMap;
|
|
IndexPairMap MBBRange;
|
|
for (SplitAnalysis::InstrPtrSet::const_iterator I = sa_.usingInstrs_.begin(),
|
|
E = sa_.usingInstrs_.end(); I != E; ++I) {
|
|
const MachineBasicBlock *MBB = (*I)->getParent();
|
|
if (!Blocks.count(MBB))
|
|
continue;
|
|
SlotIndex Idx = lis_.getInstructionIndex(*I);
|
|
DEBUG(dbgs() << " BB#" << MBB->getNumber() << '\t' << Idx << '\t' << **I);
|
|
IndexPair &IP = MBBRange[MBB];
|
|
if (!IP.first.isValid() || Idx < IP.first)
|
|
IP.first = Idx;
|
|
if (!IP.second.isValid() || Idx > IP.second)
|
|
IP.second = Idx;
|
|
}
|
|
|
|
// Create a new interval for each block.
|
|
for (SplitAnalysis::BlockPtrSet::const_iterator I = Blocks.begin(),
|
|
E = Blocks.end(); I != E; ++I) {
|
|
IndexPair &IP = MBBRange[*I];
|
|
DEBUG(dbgs() << " splitting for BB#" << (*I)->getNumber() << ": ["
|
|
<< IP.first << ';' << IP.second << ")\n");
|
|
assert(IP.first.isValid() && IP.second.isValid());
|
|
|
|
openIntv();
|
|
enterIntvBefore(IP.first);
|
|
useIntv(IP.first.getBaseIndex(), IP.second.getBoundaryIndex());
|
|
leaveIntvAfter(IP.second);
|
|
closeIntv();
|
|
}
|
|
finish();
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Sub Block Splitting
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
/// getBlockForInsideSplit - If curli is contained inside a single basic block,
|
|
/// and it wou pay to subdivide the interval inside that block, return it.
|
|
/// Otherwise return NULL. The returned block can be passed to
|
|
/// SplitEditor::splitInsideBlock.
|
|
const MachineBasicBlock *SplitAnalysis::getBlockForInsideSplit() {
|
|
// The interval must be exclusive to one block.
|
|
if (usingBlocks_.size() != 1)
|
|
return 0;
|
|
// Don't to this for less than 4 instructions. We want to be sure that
|
|
// splitting actually reduces the instruction count per interval.
|
|
if (usingInstrs_.size() < 4)
|
|
return 0;
|
|
return usingBlocks_.begin()->first;
|
|
}
|
|
|
|
/// splitInsideBlock - Split curli into multiple intervals inside MBB.
|
|
void SplitEditor::splitInsideBlock(const MachineBasicBlock *MBB) {
|
|
SmallVector<SlotIndex, 32> Uses;
|
|
Uses.reserve(sa_.usingInstrs_.size());
|
|
for (SplitAnalysis::InstrPtrSet::const_iterator I = sa_.usingInstrs_.begin(),
|
|
E = sa_.usingInstrs_.end(); I != E; ++I)
|
|
if ((*I)->getParent() == MBB)
|
|
Uses.push_back(lis_.getInstructionIndex(*I));
|
|
DEBUG(dbgs() << " splitInsideBlock BB#" << MBB->getNumber() << " for "
|
|
<< Uses.size() << " instructions.\n");
|
|
assert(Uses.size() >= 3 && "Need at least 3 instructions");
|
|
array_pod_sort(Uses.begin(), Uses.end());
|
|
|
|
// Simple algorithm: Find the largest gap between uses as determined by slot
|
|
// indices. Create new intervals for instructions before the gap and after the
|
|
// gap.
|
|
unsigned bestPos = 0;
|
|
int bestGap = 0;
|
|
DEBUG(dbgs() << " dist (" << Uses[0]);
|
|
for (unsigned i = 1, e = Uses.size(); i != e; ++i) {
|
|
int g = Uses[i-1].distance(Uses[i]);
|
|
DEBUG(dbgs() << ") -" << g << "- (" << Uses[i]);
|
|
if (g > bestGap)
|
|
bestPos = i, bestGap = g;
|
|
}
|
|
DEBUG(dbgs() << "), best: -" << bestGap << "-\n");
|
|
|
|
// bestPos points to the first use after the best gap.
|
|
assert(bestPos > 0 && "Invalid gap");
|
|
|
|
// FIXME: Don't create intervals for low densities.
|
|
|
|
// First interval before the gap. Don't create single-instr intervals.
|
|
if (bestPos > 1) {
|
|
openIntv();
|
|
enterIntvBefore(Uses.front());
|
|
useIntv(Uses.front().getBaseIndex(), Uses[bestPos-1].getBoundaryIndex());
|
|
leaveIntvAfter(Uses[bestPos-1]);
|
|
closeIntv();
|
|
}
|
|
|
|
// Second interval after the gap.
|
|
if (bestPos < Uses.size()-1) {
|
|
openIntv();
|
|
enterIntvBefore(Uses[bestPos]);
|
|
useIntv(Uses[bestPos].getBaseIndex(), Uses.back().getBoundaryIndex());
|
|
leaveIntvAfter(Uses.back());
|
|
closeIntv();
|
|
}
|
|
|
|
finish();
|
|
}
|