diff options
Diffstat (limited to 'lib/CodeGen/LiveRangeCalc.h')
| -rw-r--r-- | lib/CodeGen/LiveRangeCalc.h | 78 |
1 files changed, 42 insertions, 36 deletions
diff --git a/lib/CodeGen/LiveRangeCalc.h b/lib/CodeGen/LiveRangeCalc.h index 345d6c4..90bf971 100644 --- a/lib/CodeGen/LiveRangeCalc.h +++ b/lib/CodeGen/LiveRangeCalc.h @@ -40,12 +40,6 @@ class LiveRangeCalc { MachineDominatorTree *DomTree; VNInfo::Allocator *Alloc; - /// Seen - Bit vector of active entries in LiveOut, also used as a visited - /// set by findReachingDefs. One entry per basic block, indexed by block - /// number. This is kept as a separate bit vector because it can be cleared - /// quickly when switching live ranges. - BitVector Seen; - /// LiveOutPair - A value and the block that defined it. The domtree node is /// redundant, it can be computed as: MDT[Indexes.getMBBFromIndex(VNI->def)]. typedef std::pair<VNInfo*, MachineDomTreeNode*> LiveOutPair; @@ -53,8 +47,14 @@ class LiveRangeCalc { /// LiveOutMap - Map basic blocks to the value leaving the block. typedef IndexedMap<LiveOutPair, MBB2NumberFunctor> LiveOutMap; - /// LiveOut - Map each basic block where a live range is live out to the - /// live-out value and its defining block. + /// Bit vector of active entries in LiveOut, also used as a visited set by + /// findReachingDefs. One entry per basic block, indexed by block number. + /// This is kept as a separate bit vector because it can be cleared quickly + /// when switching live ranges. + BitVector Seen; + + /// Map each basic block where a live range is live out to the live-out value + /// and its defining block. /// /// For every basic block, MBB, one of these conditions shall be true: /// @@ -70,7 +70,7 @@ class LiveRangeCalc { /// /// The map can be shared by multiple live ranges as long as no two are /// live-out of the same block. - LiveOutMap LiveOut; + LiveOutMap Map; /// LiveInBlock - Information about a basic block where a live range is known /// to be live-in, but the value has not yet been determined. @@ -101,17 +101,17 @@ class LiveRangeCalc { /// used to add entries directly. SmallVector<LiveInBlock, 16> LiveIn; - /// Assuming that LI is live-in to KillMBB and killed at Kill, find the set - /// of defs that can reach it. + /// Assuming that @p LR is live-in to @p UseMBB, find the set of defs that can + /// reach it. /// - /// If only one def can reach Kill, all paths from the def to kill are added - /// to LI, and the function returns true. + /// If only one def can reach @p UseMBB, all paths from the def to @p UseMBB + /// are added to @p LR, and the function returns true. /// - /// If multiple values can reach Kill, the blocks that need LI to be live in - /// are added to the LiveIn array, and the function returns false. + /// If multiple values can reach @p UseMBB, the blocks that need @p LR to be + /// live in are added to the LiveIn array, and the function returns false. /// /// PhysReg, when set, is used to verify live-in lists on basic blocks. - bool findReachingDefs(LiveRange &LR, MachineBasicBlock &KillMBB, + bool findReachingDefs(LiveRange &LR, MachineBasicBlock &UseMBB, SlotIndex Kill, unsigned PhysReg); /// updateSSA - Compute the values that will be live in to all requested @@ -121,8 +121,18 @@ class LiveRangeCalc { /// blocks. No values are read from the live ranges. void updateSSA(); - /// Add liveness as specified in the LiveIn vector. - void updateLiveIns(); + /// Transfer information from the LiveIn vector to the live ranges and update + /// the given @p LiveOuts. + void updateFromLiveIns(); + + /// Extend the live range of @p LR to reach all uses of Reg. + /// + /// All uses must be jointly dominated by existing liveness. PHI-defs are + /// inserted as needed to preserve SSA form. + void extendToUses(LiveRange &LR, unsigned Reg, unsigned LaneMask); + + /// Reset Map and Seen fields. + void resetLiveOutMap(); public: LiveRangeCalc() : MF(nullptr), MRI(nullptr), Indexes(nullptr), @@ -152,37 +162,33 @@ public: // Modify existing live ranges. // - /// extend - Extend the live range of LI to reach Kill. + /// Extend the live range of @p LR to reach @p Use. /// - /// The existing values in LI must be live so they jointly dominate Kill. If - /// Kill is not dominated by a single existing value, PHI-defs are inserted - /// as required to preserve SSA form. If Kill is known to be dominated by a - /// single existing value, Alloc may be null. + /// The existing values in @p LR must be live so they jointly dominate @p Use. + /// If @p Use is not dominated by a single existing value, PHI-defs are + /// inserted as required to preserve SSA form. /// /// PhysReg, when set, is used to verify live-in lists on basic blocks. - void extend(LiveRange &LR, SlotIndex Kill, unsigned PhysReg = 0); + void extend(LiveRange &LR, SlotIndex Use, unsigned PhysReg = 0); /// createDeadDefs - Create a dead def in LI for every def operand of Reg. /// Each instruction defining Reg gets a new VNInfo with a corresponding /// minimal live range. void createDeadDefs(LiveRange &LR, unsigned Reg); - /// createDeadDefs - Create a dead def in LI for every def of LI->reg. - void createDeadDefs(LiveInterval &LI) { - createDeadDefs(LI, LI.reg); - } - - /// extendToUses - Extend the live range of LI to reach all uses of Reg. + /// Extend the live range of @p LR to reach all uses of Reg. /// /// All uses must be jointly dominated by existing liveness. PHI-defs are /// inserted as needed to preserve SSA form. - void extendToUses(LiveRange &LR, unsigned Reg); - - /// extendToUses - Extend the live range of LI to reach all uses of LI->reg. - void extendToUses(LiveInterval &LI) { - extendToUses(LI, LI.reg); + void extendToUses(LiveRange &LR, unsigned PhysReg) { + extendToUses(LR, PhysReg, ~0u); } + /// Calculates liveness for the register specified in live interval @p LI. + /// Creates subregister live ranges as needed if subreg liveness tracking is + /// enabled. + void calculate(LiveInterval &LI); + //===--------------------------------------------------------------------===// // Low-level interface. //===--------------------------------------------------------------------===// @@ -204,7 +210,7 @@ public: /// addLiveInBlock(). void setLiveOutValue(MachineBasicBlock *MBB, VNInfo *VNI) { Seen.set(MBB->getNumber()); - LiveOut[MBB] = LiveOutPair(VNI, nullptr); + Map[MBB] = LiveOutPair(VNI, nullptr); } /// addLiveInBlock - Add a block with an unknown live-in value. 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