-//===---------- SplitKit.cpp - Toolkit for splitting live ranges ----------===//
+//===-------- SplitKit.cpp - Toolkit for splitting live ranges --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
//
//===----------------------------------------------------------------------===//
-#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/IntEqClasses.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/CodeGen/SlotIndexes.h"
+#include <string>
+
namespace llvm {
class LiveInterval;
class LiveIntervals;
+class LiveRangeEdit;
class MachineInstr;
class MachineLoop;
class MachineLoopInfo;
class MachineRegisterInfo;
class TargetInstrInfo;
+class TargetRegisterInfo;
class VirtRegMap;
class VNInfo;
+class raw_ostream;
+
+/// At some point we should just include MachineDominators.h:
+class MachineDominatorTree;
+template <class NodeT> class DomTreeNodeBase;
+typedef DomTreeNodeBase<MachineBasicBlock> MachineDomTreeNode;
+
+
+/// EdgeBundles - Group CFG edges into equivalence classes where registers must
+/// be allocated identically. This annotates the CFG to form a bipartite graph
+/// where each block is connected to an ingoing and an outgoing bundle.
+/// Edge bundles are simply numbered, there is no object representation.
+class EdgeBundles {
+ const MachineFunction *MF;
+
+ /// EC - Each edge bundle is an equivalence class. The keys are:
+ /// 2*BB->getNumber() -> Ingoing bundle.
+ /// 2*BB->getNumber()+1 -> Outgoing bundle.
+ IntEqClasses EC;
+
+public:
+ /// compute - Compute the edge bundles for MF. Bundles depend only on the CFG.
+ void compute(const MachineFunction *MF);
+
+ /// getBundle - Return the ingoing (Out = false) or outgoing (Out = true)
+ /// bundle number for basic block #N
+ unsigned getBundle(unsigned N, bool Out) const { return EC[2 * N + Out]; }
+
+ /// getMachineFunction - Return the last machine function computed.
+ const MachineFunction *getMachineFunction() const { return MF; }
+
+ /// view - Visualize the annotated bipartite CFG with Graphviz.
+ void view() const;
+};
+
+/// Specialize WriteGraph, the standard implementation won't work.
+raw_ostream &WriteGraph(raw_ostream &O, const EdgeBundles &G,
+ bool ShortNames = false,
+ const std::string &Title = "");
+
/// SplitAnalysis - Analyze a LiveInterval, looking for live range splitting
/// opportunities.
/// split.
void analyze(const LiveInterval *li);
- const LiveInterval *getCurLI() { return curli_; }
-
/// clear - clear all data structures so SplitAnalysis is ready to analyze a
/// new interval.
void clear();
typedef SmallPtrSet<const MachineBasicBlock*, 16> BlockPtrSet;
typedef SmallPtrSet<const MachineLoop*, 16> LoopPtrSet;
+ // Print a set of blocks with use counts.
+ void print(const BlockPtrSet&, raw_ostream&) const;
+
// Sets of basic blocks surrounding a machine loop.
struct LoopBlocks {
BlockPtrSet Loop; // Blocks in the loop.
}
};
+ // Print loop blocks with use counts.
+ void print(const LoopBlocks&, raw_ostream&) const;
+
// Calculate the block sets surrounding the loop.
void getLoopBlocks(const MachineLoop *Loop, LoopBlocks &Blocks);
bool canSplitCriticalExits(const LoopBlocks &Blocks,
BlockPtrSet &CriticalExits);
+ /// getCriticalPreds - Get the set of loop predecessors with critical edges to
+ /// blocks outside the loop that have curli live in. We don't have to break
+ /// these edges, but they do require special treatment.
+ void getCriticalPreds(const LoopBlocks &Blocks, BlockPtrSet &CriticalPreds);
+
+ /// getSplitLoops - Get the set of loops that have curli uses and would be
+ /// profitable to split.
+ void getSplitLoops(LoopPtrSet&);
+
/// getBestSplitLoop - Return the loop where curli may best be split to a
/// separate register, or NULL.
const MachineLoop *getBestSplitLoop();
+ /// isBypassLoop - Return true if curli is live through Loop and has no uses
+ /// inside the loop. Bypass loops are candidates for splitting because it can
+ /// prevent interference inside the loop.
+ bool isBypassLoop(const MachineLoop *Loop);
+
+ /// getBypassLoops - Get all the maximal bypass loops. These are the bypass
+ /// loops whose parent is not a bypass loop.
+ void getBypassLoops(LoopPtrSet&);
+
/// getMultiUseBlocks - Add basic blocks to Blocks that may benefit from
/// having curli split to a new live interval. Return true if Blocks can be
/// passed to SplitEditor::splitSingleBlocks.
/// Values in parentli_ may map to any number of openli_ values, including 0.
class LiveIntervalMap {
LiveIntervals &lis_;
+ MachineDominatorTree &mdt_;
// The parent interval is never changed.
const LiveInterval &parentli_;
// values not present (unknown/unmapped).
ValueMap valueMap_;
+ typedef std::pair<VNInfo*, MachineDomTreeNode*> LiveOutPair;
+ typedef DenseMap<MachineBasicBlock*,LiveOutPair> LiveOutMap;
+
+ // liveOutCache_ - Map each basic block where li_ is live out to the live-out
+ // value and its defining block. One of these conditions shall be true:
+ //
+ // 1. !liveOutCache_.count(MBB)
+ // 2. liveOutCache_[MBB].second.getNode() == MBB
+ // 3. forall P in preds(MBB): liveOutCache_[P] == liveOutCache_[MBB]
+ //
+ // This is only a cache, the values can be computed as:
+ //
+ // VNI = li_->getVNInfoAt(lis_.getMBBEndIdx(MBB))
+ // Node = mbt_[lis_.getMBBFromIndex(VNI->def)]
+ //
+ // The cache is also used as a visiteed set by mapValue().
+ LiveOutMap liveOutCache_;
+
public:
LiveIntervalMap(LiveIntervals &lis,
+ MachineDominatorTree &mdt,
const LiveInterval &parentli)
- : lis_(lis), parentli_(parentli), li_(0) {}
+ : lis_(lis), mdt_(mdt), parentli_(parentli), li_(0) {}
/// reset - clear all data structures and start a new live interval.
void reset(LiveInterval *);
// 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 include
// Idx. Return the found VNInfo, or NULL.
- VNInfo *extendTo(MachineBasicBlock *MBB, SlotIndex Idx);
+ VNInfo *extendTo(const MachineBasicBlock *MBB, SlotIndex Idx);
/// isMapped - Return true is ParentVNI is a known mapped value. It may be a
/// simple 1-1 mapping or a complex mapping to later defs.
/// All needed values whose def is not inside [Start;End) must be defined
/// beforehand so mapValue will work.
void addRange(SlotIndex Start, SlotIndex End);
-
- /// defByCopyFrom - Insert a copy from Reg to li, assuming that Reg carries
- /// ParentVNI. Add a minimal live range for the new value and return it.
- VNInfo *defByCopyFrom(unsigned Reg,
- const VNInfo *ParentVNI,
- MachineBasicBlock &MBB,
- MachineBasicBlock::iterator I);
-
};
/// - Mark the ranges where the new interval is used with useIntv*
/// - Mark the places where the interval is exited with exitIntv*.
/// - Finish the current interval with closeIntv and repeat from 2.
-/// - Rewrite instructions with rewrite().
+/// - Rewrite instructions with finish().
///
class SplitEditor {
SplitAnalysis &sa_;
VirtRegMap &vrm_;
MachineRegisterInfo &mri_;
const TargetInstrInfo &tii_;
+ const TargetRegisterInfo &tri_;
- /// curli_ - The immutable interval we are currently splitting.
- const LiveInterval *const curli_;
+ /// edit_ - The current parent register and new intervals created.
+ LiveRangeEdit &edit_;
/// dupli_ - Created as a copy of curli_, ranges are carved out as new
/// intervals get added through openIntv / closeIntv. This is used to avoid
/// Currently open LiveInterval.
LiveIntervalMap openli_;
- /// createInterval - Create a new virtual register and LiveInterval with same
- /// register class and spill slot as curli.
- LiveInterval *createInterval();
-
- /// All the new intervals created for this split are added to intervals_.
- SmallVectorImpl<LiveInterval*> &intervals_;
-
- /// The index into intervals_ of the first interval we added. There may be
- /// others from before we got it.
- unsigned firstInterval;
+ /// defFromParent - Define Reg from ParentVNI at UseIdx using either
+ /// rematerialization or a COPY from parent. Return the new value.
+ VNInfo *defFromParent(LiveIntervalMap &Reg,
+ VNInfo *ParentVNI,
+ SlotIndex UseIdx,
+ MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator I);
/// intervalsLiveAt - Return true if any member of intervals_ is live at Idx.
bool intervalsLiveAt(SlotIndex Idx) const;
/// truncating any overlap with intervals_.
void addTruncSimpleRange(SlotIndex Start, SlotIndex End, VNInfo *VNI);
+ /// criticalPreds_ - Set of basic blocks where both dupli and openli should be
+ /// live out because of a critical edge.
+ SplitAnalysis::BlockPtrSet criticalPreds_;
+
+ /// computeRemainder - Compute the dupli liveness as the complement of all the
+ /// new intervals.
+ void computeRemainder();
+
+ /// rewrite - Rewrite all uses of reg to use the new registers.
+ void rewrite(unsigned reg);
+
public:
/// Create a new SplitEditor for editing the LiveInterval analyzed by SA.
/// Newly created intervals will be appended to newIntervals.
SplitEditor(SplitAnalysis &SA, LiveIntervals&, VirtRegMap&,
- SmallVectorImpl<LiveInterval*> &newIntervals);
+ MachineDominatorTree&, LiveRangeEdit&);
/// getAnalysis - Get the corresponding analysis.
SplitAnalysis &getAnalysis() { return sa_; }
/// LiveInterval, and ranges can be trimmed.
void closeIntv();
- /// rewrite - after all the new live ranges have been created, rewrite
- /// instructions using curli to use the new intervals.
- void rewrite();
+ /// finish - after all the new live ranges have been created, compute the
+ /// remaining live range, and rewrite instructions to use the new registers.
+ void finish();
// ===--- High level methods ---===
projects / oota-llvm.git / blobdiff