//===-- SimpleRegisterCoalescing.h - Register Coalescing --------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements a simple register copy coalescing phase. // //===----------------------------------------------------------------------===// #ifndef LLVM_CODEGEN_SIMPLE_REGISTER_COALESCING_H #define LLVM_CODEGEN_SIMPLE_REGISTER_COALESCING_H #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/LiveIntervalAnalysis.h" #include "llvm/CodeGen/RegisterCoalescer.h" #include "llvm/ADT/BitVector.h" namespace llvm { class SimpleRegisterCoalescing; class LiveDebugVariables; class TargetRegisterInfo; class TargetInstrInfo; class VirtRegMap; class MachineLoopInfo; /// CopyRec - Representation for copy instructions in coalescer queue. /// struct CopyRec { MachineInstr *MI; unsigned LoopDepth; CopyRec(MachineInstr *mi, unsigned depth) : MI(mi), LoopDepth(depth) {} }; class SimpleRegisterCoalescing : public MachineFunctionPass, public RegisterCoalescer { MachineFunction* mf_; MachineRegisterInfo* mri_; const TargetMachine* tm_; const TargetRegisterInfo* tri_; const TargetInstrInfo* tii_; LiveIntervals *li_; LiveDebugVariables *ldv_; const MachineLoopInfo* loopInfo; AliasAnalysis *AA; DenseMap<const TargetRegisterClass*, BitVector> allocatableRCRegs_; /// JoinedCopies - Keep track of copies eliminated due to coalescing. /// SmallPtrSet<MachineInstr*, 32> JoinedCopies; /// ReMatCopies - Keep track of copies eliminated due to remat. /// SmallPtrSet<MachineInstr*, 32> ReMatCopies; /// ReMatDefs - Keep track of definition instructions which have /// been remat'ed. SmallPtrSet<MachineInstr*, 8> ReMatDefs; public: static char ID; // Pass identifcation, replacement for typeid SimpleRegisterCoalescing() : MachineFunctionPass(ID) { initializeSimpleRegisterCoalescingPass(*PassRegistry::getPassRegistry()); } virtual void getAnalysisUsage(AnalysisUsage &AU) const; virtual void releaseMemory(); /// runOnMachineFunction - pass entry point virtual bool runOnMachineFunction(MachineFunction&); bool coalesceFunction(MachineFunction &mf, RegallocQuery &) { // This runs as an independent pass, so don't do anything. return false; } /// print - Implement the dump method. virtual void print(raw_ostream &O, const Module* = 0) const; private: /// joinIntervals - join compatible live intervals void joinIntervals(); /// CopyCoalesceInMBB - Coalesce copies in the specified MBB, putting /// copies that cannot yet be coalesced into the "TryAgain" list. void CopyCoalesceInMBB(MachineBasicBlock *MBB, std::vector<CopyRec> &TryAgain); /// JoinCopy - Attempt to join intervals corresponding to SrcReg/DstReg, /// which are the src/dst of the copy instruction CopyMI. This returns true /// if the copy was successfully coalesced away. If it is not currently /// possible to coalesce this interval, but it may be possible if other /// things get coalesced, then it returns true by reference in 'Again'. bool JoinCopy(CopyRec &TheCopy, bool &Again); /// JoinIntervals - Attempt to join these two intervals. On failure, this /// returns false. The output "SrcInt" will not have been modified, so we can /// use this information below to update aliases. bool JoinIntervals(CoalescerPair &CP); /// Return true if the two specified registers belong to different register /// classes. The registers may be either phys or virt regs. bool differingRegisterClasses(unsigned RegA, unsigned RegB) const; /// AdjustCopiesBackFrom - We found a non-trivially-coalescable copy. If /// the source value number is defined by a copy from the destination reg /// see if we can merge these two destination reg valno# into a single /// value number, eliminating a copy. bool AdjustCopiesBackFrom(const CoalescerPair &CP, MachineInstr *CopyMI); /// HasOtherReachingDefs - Return true if there are definitions of IntB /// other than BValNo val# that can reach uses of AValno val# of IntA. bool HasOtherReachingDefs(LiveInterval &IntA, LiveInterval &IntB, VNInfo *AValNo, VNInfo *BValNo); /// RemoveCopyByCommutingDef - We found a non-trivially-coalescable copy. /// If the source value number is defined by a commutable instruction and /// its other operand is coalesced to the copy dest register, see if we /// can transform the copy into a noop by commuting the definition. bool RemoveCopyByCommutingDef(const CoalescerPair &CP,MachineInstr *CopyMI); /// TrimLiveIntervalToLastUse - If there is a last use in the same basic /// block as the copy instruction, trim the ive interval to the last use /// and return true. bool TrimLiveIntervalToLastUse(SlotIndex CopyIdx, MachineBasicBlock *CopyMBB, LiveInterval &li, const LiveRange *LR); /// ReMaterializeTrivialDef - If the source of a copy is defined by a trivial /// computation, replace the copy by rematerialize the definition. /// If PreserveSrcInt is true, make sure SrcInt is valid after the call. bool ReMaterializeTrivialDef(LiveInterval &SrcInt, bool PreserveSrcInt, unsigned DstReg, unsigned DstSubIdx, MachineInstr *CopyMI); /// shouldJoinPhys - Return true if a physreg copy should be joined. bool shouldJoinPhys(CoalescerPair &CP); /// isWinToJoinCrossClass - Return true if it's profitable to coalesce /// two virtual registers from different register classes. bool isWinToJoinCrossClass(unsigned SrcReg, unsigned DstReg, const TargetRegisterClass *SrcRC, const TargetRegisterClass *DstRC, const TargetRegisterClass *NewRC); /// UpdateRegDefsUses - Replace all defs and uses of SrcReg to DstReg and /// update the subregister number if it is not zero. If DstReg is a /// physical register and the existing subregister number of the def / use /// being updated is not zero, make sure to set it to the correct physical /// subregister. void UpdateRegDefsUses(const CoalescerPair &CP); /// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy. /// Return true if live interval is removed. bool ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI); /// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially /// extended by a dead copy. Mark the last use (if any) of the val# as kill /// as ends the live range there. If there isn't another use, then this /// live range is dead. Return true if live interval is removed. bool ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI); /// RemoveDeadDef - If a def of a live interval is now determined dead, /// remove the val# it defines. If the live interval becomes empty, remove /// it as well. bool RemoveDeadDef(LiveInterval &li, MachineInstr *DefMI); /// RemoveCopyFlag - If DstReg is no longer defined by CopyMI, clear the /// VNInfo copy flag for DstReg and all aliases. void RemoveCopyFlag(unsigned DstReg, const MachineInstr *CopyMI); /// lastRegisterUse - Returns the last use of the specific register between /// cycles Start and End or NULL if there are no uses. MachineOperand *lastRegisterUse(SlotIndex Start, SlotIndex End, unsigned Reg, SlotIndex &LastUseIdx) const; /// markAsJoined - Remember that CopyMI has already been joined. void markAsJoined(MachineInstr *CopyMI); }; } // End llvm namespace #endif