//
//===----------------------------------------------------------------------===//
+#ifndef LLVM_CODEGEN_SPLITKIT_H
+#define LLVM_CODEGEN_SPLITKIT_H
+
+#include "LiveRangeCalc.h"
#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/CodeGen/SlotIndexes.h"
namespace llvm {
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;
-
-
/// SplitAnalysis - Analyze a LiveInterval, looking for live range splitting
/// opportunities.
class SplitAnalysis {
/// 1. | o---x | Internal to block. Variable is only live in this block.
/// 2. |---x | Live-in, kill.
/// 3. | o---| Def, live-out.
- /// 4. |---x o---| Live-in, kill, def, live-out.
+ /// 4. |---x o---| Live-in, kill, def, live-out. Counted by NumGapBlocks.
/// 5. |---o---o---| Live-through with uses or defs.
- /// 6. |-----------| Live-through without uses. Transparent.
+ /// 6. |-----------| Live-through without uses. Counted by NumThroughBlocks.
+ ///
+ /// Two BlockInfo entries are created for template 4. One for the live-in
+ /// segment, and one for the live-out segment. These entries look as if the
+ /// block were split in the middle where the live range isn't live.
+ ///
+ /// Live-through blocks without any uses don't get BlockInfo entries. They
+ /// are simply listed in ThroughBlocks instead.
///
struct BlockInfo {
MachineBasicBlock *MBB;
- SlotIndex FirstUse; ///< First instr using current reg.
- SlotIndex LastUse; ///< Last instr using current reg.
- SlotIndex Kill; ///< Interval end point inside block.
- SlotIndex Def; ///< Interval start point inside block.
- bool LiveThrough; ///< Live in whole block (Templ 5. or 6. above).
+ SlotIndex FirstInstr; ///< First instr accessing current reg.
+ SlotIndex LastInstr; ///< Last instr accessing current reg.
+ SlotIndex FirstDef; ///< First non-phi valno->def, or SlotIndex().
bool LiveIn; ///< Current reg is live in.
bool LiveOut; ///< Current reg is live out.
+
+ /// isOneInstr - Returns true when this BlockInfo describes a single
+ /// instruction.
+ bool isOneInstr() const {
+ return SlotIndex::isSameInstr(FirstInstr, LastInstr);
+ }
};
private:
/// UseBlocks - Blocks where CurLI has uses.
SmallVector<BlockInfo, 8> UseBlocks;
+ /// NumGapBlocks - Number of duplicate entries in UseBlocks for blocks where
+ /// the live range has a gap.
+ unsigned NumGapBlocks;
+
/// ThroughBlocks - Block numbers where CurLI is live through without uses.
- SmallVector<unsigned, 8> ThroughBlocks;
+ BitVector ThroughBlocks;
+
+ /// NumThroughBlocks - Number of live-through blocks.
+ unsigned NumThroughBlocks;
+
+ /// DidRepairRange - analyze was forced to shrinkToUses().
+ bool DidRepairRange;
SlotIndex computeLastSplitPoint(unsigned Num);
/// split.
void analyze(const LiveInterval *li);
+ /// didRepairRange() - Returns true if CurLI was invalid and has been repaired
+ /// by analyze(). This really shouldn't happen, but sometimes the coalescer
+ /// can create live ranges that end in mid-air.
+ bool didRepairRange() const { return DidRepairRange; }
+
/// clear - clear all data structures so SplitAnalysis is ready to analyze a
/// new interval.
void clear();
/// getUseBlocks - Return an array of BlockInfo objects for the basic blocks
/// where CurLI has uses.
- ArrayRef<BlockInfo> getUseBlocks() { return UseBlocks; }
+ ArrayRef<BlockInfo> getUseBlocks() const { return UseBlocks; }
- /// getThroughBlocks - Return an array of block numbers where CurLI is live
- /// through without uses.
- ArrayRef<unsigned> getThroughBlocks() { return ThroughBlocks; }
+ /// getNumThroughBlocks - Return the number of through blocks.
+ unsigned getNumThroughBlocks() const { return NumThroughBlocks; }
+
+ /// isThroughBlock - Return true if CurLI is live through MBB without uses.
+ bool isThroughBlock(unsigned MBB) const { return ThroughBlocks.test(MBB); }
+
+ /// getThroughBlocks - Return the set of through blocks.
+ const BitVector &getThroughBlocks() const { return ThroughBlocks; }
+
+ /// getNumLiveBlocks - Return the number of blocks where CurLI is live.
+ unsigned getNumLiveBlocks() const {
+ return getUseBlocks().size() - NumGapBlocks + getNumThroughBlocks();
+ }
+
+ /// countLiveBlocks - Return the number of blocks where li is live. This is
+ /// guaranteed to return the same number as getNumLiveBlocks() after calling
+ /// analyze(li).
+ unsigned countLiveBlocks(const LiveInterval *li) const;
typedef SmallPtrSet<const MachineBasicBlock*, 16> BlockPtrSet;
- /// 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.
- bool getMultiUseBlocks(BlockPtrSet &Blocks);
+ /// shouldSplitSingleBlock - Returns true if it would help to create a local
+ /// live range for the instructions in BI. There is normally no benefit to
+ /// creating a live range for a single instruction, but it does enable
+ /// register class inflation if the instruction has a restricted register
+ /// class.
+ ///
+ /// @param BI The block to be isolated.
+ /// @param SingleInstrs True when single instructions should be isolated.
+ bool shouldSplitSingleBlock(const BlockInfo &BI, bool SingleInstrs) const;
};
const TargetInstrInfo &TII;
const TargetRegisterInfo &TRI;
+public:
+
+ /// ComplementSpillMode - Select how the complement live range should be
+ /// created. SplitEditor automatically creates interval 0 to contain
+ /// anything that isn't added to another interval. This complement interval
+ /// can get quite complicated, and it can sometimes be an advantage to allow
+ /// it to overlap the other intervals. If it is going to spill anyway, no
+ /// registers are wasted by keeping a value in two places at the same time.
+ enum ComplementSpillMode {
+ /// SM_Partition(Default) - Try to create the complement interval so it
+ /// doesn't overlap any other intervals, and the original interval is
+ /// partitioned. This may require a large number of back copies and extra
+ /// PHI-defs. Only segments marked with overlapIntv will be overlapping.
+ SM_Partition,
+
+ /// SM_Size - Overlap intervals to minimize the number of inserted COPY
+ /// instructions. Copies to the complement interval are hoisted to their
+ /// common dominator, so only one COPY is required per value in the
+ /// complement interval. This also means that no extra PHI-defs need to be
+ /// inserted in the complement interval.
+ SM_Size,
+
+ /// SM_Speed - Overlap intervals to minimize the expected execution
+ /// frequency of the inserted copies. This is very similar to SM_Size, but
+ /// the complement interval may get some extra PHI-defs.
+ SM_Speed
+ };
+
+private:
+
/// Edit - The current parent register and new intervals created.
LiveRangeEdit *Edit;
/// openIntv will be 1.
unsigned OpenIdx;
+ /// The current spill mode, selected by reset().
+ ComplementSpillMode SpillMode;
+
+ /// Parent interval values where the complement interval may be overlapping
+ /// other intervals.
+ SmallPtrSet<const VNInfo*, 8> OverlappedComplement;
+
typedef IntervalMap<SlotIndex, unsigned> RegAssignMap;
/// Allocator for the interval map. This will eventually be shared with
/// The new value has no live ranges anywhere.
ValueMap Values;
- typedef std::pair<VNInfo*, MachineDomTreeNode*> LiveOutPair;
- typedef IndexedMap<LiveOutPair, MBB2NumberFunctor> LiveOutMap;
-
- // LiveOutCache - Map each basic block where a new register 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 = Edit.get(RegIdx)->getVNInfoAt(LIS.getMBBEndIdx(MBB))
- // Node = mbt_[LIS.getMBBFromIndex(VNI->def)]
- //
- // The cache is also used as a visited set by extendRange(). It can be shared
- // by all the new registers because at most one is live out of each block.
- LiveOutMap LiveOutCache;
-
- // LiveOutSeen - Indexed by MBB->getNumber(), a bit is set for each valid
- // entry in LiveOutCache.
- BitVector LiveOutSeen;
+ /// LRCalc - Cache for computing live ranges and SSA update. Each instance
+ /// can only handle non-overlapping live ranges, so use a separate
+ /// LiveRangeCalc instance for the complement interval when in spill mode.
+ LiveRangeCalc LRCalc[2];
+
+ /// getLRCalc - Return the LRCalc to use for RegIdx. In spill mode, the
+ /// complement interval can overlap the other intervals, so it gets its own
+ /// LRCalc instance. When not in spill mode, all intervals can share one.
+ LiveRangeCalc &getLRCalc(unsigned RegIdx) {
+ return LRCalc[SpillMode != SM_Partition && RegIdx != 0];
+ }
/// defValue - define a value in RegIdx from ParentVNI at Idx.
/// Idx does not have to be ParentVNI->def, but it must be contained within
/// of the number of defs.
void markComplexMapped(unsigned RegIdx, const VNInfo *ParentVNI);
+ /// markOverlappedComplement - Mark ParentVNI as being overlapped in the
+ /// complement interval. The complement interval may overlap other intervals
+ /// after overlapIntv has been called, or when in spill mode.
+ void markOverlappedComplement(const VNInfo *ParentVNI);
+
+ /// needsRecompute - Returns true if the live range of ParentVNI needs to be
+ /// recomputed in RegIdx using LiveRangeCalc::extend. This is the case if
+ /// the value has been rematerialized, or when back-copies have been hoisted
+ /// in spill mode.
+ bool needsRecompute(unsigned RegIdx, const VNInfo *ParentVNI);
+
/// defFromParent - Define Reg from ParentVNI at UseIdx using either
/// rematerialization or a COPY from parent. Return the new value.
VNInfo *defFromParent(unsigned RegIdx,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I);
- /// extendRange - Extend the live range of Edit.get(RegIdx) so it reaches Idx.
- /// Insert PHIDefs as needed to preserve SSA form.
- void extendRange(unsigned RegIdx, SlotIndex Idx);
-
- /// updateSSA - Insert PHIDefs as necessary and update LiveOutCache such that
- /// Edit.get(RegIdx) is live-in to all the blocks in LiveIn.
- /// Return the value that is eventually live-in to IdxMBB.
- VNInfo *updateSSA(unsigned RegIdx,
- SmallVectorImpl<MachineDomTreeNode*> &LiveIn,
- SlotIndex Idx,
- const MachineBasicBlock *IdxMBB);
-
- /// transferSimpleValues - Transfer simply defined values to the new ranges.
- /// Return true if any complex ranges were skipped.
- bool transferSimpleValues();
+ /// transferValues - Transfer values to the new ranges.
+ /// Return true if any ranges were skipped.
+ bool transferValues();
/// extendPHIKillRanges - Extend the ranges of all values killed by original
/// parent PHIDefs.
MachineDominatorTree&);
/// reset - Prepare for a new split.
- void reset(LiveRangeEdit&);
+ void reset(LiveRangeEdit&, ComplementSpillMode = SM_Partition);
/// Create a new virtual register and live interval.
- void openIntv();
+ /// Return the interval index, starting from 1. Interval index 0 is the
+ /// implicit complement interval.
+ unsigned openIntv();
+
+ /// currentIntv - Return the current interval index.
+ unsigned currentIntv() const { return OpenIdx; }
+
+ /// selectIntv - Select a previously opened interval index.
+ void selectIntv(unsigned Idx);
/// enterIntvBefore - Enter the open interval before the instruction at Idx.
/// If the parent interval is not live before Idx, a COPY is not inserted.
/// Return the beginning of the new live range.
SlotIndex enterIntvBefore(SlotIndex Idx);
+ /// enterIntvAfter - Enter the open interval after the instruction at Idx.
+ /// Return the beginning of the new live range.
+ SlotIndex enterIntvAfter(SlotIndex Idx);
+
/// enterIntvAtEnd - Enter the open interval at the end of MBB.
/// Use the open interval from he inserted copy to the MBB end.
/// Return the beginning of the new live range.
///
void overlapIntv(SlotIndex Start, SlotIndex End);
- /// closeIntv - Indicate that we are done editing the currently open
- /// LiveInterval, and ranges can be trimmed.
- void closeIntv();
-
/// 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();
+ /// @param LRMap When not null, this vector will map each live range in Edit
+ /// back to the indices returned by openIntv.
+ /// There may be extra indices created by dead code elimination.
+ void finish(SmallVectorImpl<unsigned> *LRMap = 0);
/// dump - print the current interval maping to dbgs().
void dump() const;
// ===--- High level methods ---===
- /// splitSingleBlocks - Split CurLI into a separate live interval inside each
- /// basic block in Blocks.
- void splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks);
+ /// splitSingleBlock - Split CurLI into a separate live interval around the
+ /// uses in a single block. This is intended to be used as part of a larger
+ /// split, and doesn't call finish().
+ void splitSingleBlock(const SplitAnalysis::BlockInfo &BI);
+
+ /// splitLiveThroughBlock - Split CurLI in the given block such that it
+ /// enters the block in IntvIn and leaves it in IntvOut. There may be uses in
+ /// the block, but they will be ignored when placing split points.
+ ///
+ /// @param MBBNum Block number.
+ /// @param IntvIn Interval index entering the block.
+ /// @param LeaveBefore When set, leave IntvIn before this point.
+ /// @param IntvOut Interval index leaving the block.
+ /// @param EnterAfter When set, enter IntvOut after this point.
+ void splitLiveThroughBlock(unsigned MBBNum,
+ unsigned IntvIn, SlotIndex LeaveBefore,
+ unsigned IntvOut, SlotIndex EnterAfter);
+
+ /// splitRegInBlock - Split CurLI in the given block such that it enters the
+ /// block in IntvIn and leaves it on the stack (or not at all). Split points
+ /// are placed in a way that avoids putting uses in the stack interval. This
+ /// may require creating a local interval when there is interference.
+ ///
+ /// @param BI Block descriptor.
+ /// @param IntvIn Interval index entering the block. Not 0.
+ /// @param LeaveBefore When set, leave IntvIn before this point.
+ void splitRegInBlock(const SplitAnalysis::BlockInfo &BI,
+ unsigned IntvIn, SlotIndex LeaveBefore);
+
+ /// splitRegOutBlock - Split CurLI in the given block such that it enters the
+ /// block on the stack (or isn't live-in at all) and leaves it in IntvOut.
+ /// Split points are placed to avoid interference and such that the uses are
+ /// not in the stack interval. This may require creating a local interval
+ /// when there is interference.
+ ///
+ /// @param BI Block descriptor.
+ /// @param IntvOut Interval index leaving the block.
+ /// @param EnterAfter When set, enter IntvOut after this point.
+ void splitRegOutBlock(const SplitAnalysis::BlockInfo &BI,
+ unsigned IntvOut, SlotIndex EnterAfter);
};
}
+
+#endif