X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTarget%2FARM%2FThumb2SizeReduction.cpp;h=49a69fd3a6a640bf350b132b5dcae5f7b52b8204;hb=12af22e8cc217827cf4f118b0f5e4ebbda9925ae;hp=da3701d390a05c700b13edb96d355753cc92c864;hpb=4b322e58b77d16f103d88a3af3a4ebd2675245a0;p=oota-llvm.git diff --git a/lib/Target/ARM/Thumb2SizeReduction.cpp b/lib/Target/ARM/Thumb2SizeReduction.cpp index da3701d390a..49a69fd3a6a 100644 --- a/lib/Target/ARM/Thumb2SizeReduction.cpp +++ b/lib/Target/ARM/Thumb2SizeReduction.cpp @@ -7,22 +7,25 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "t2-reduce-size" #include "ARM.h" -#include "ARMAddressingModes.h" -#include "ARMBaseRegisterInfo.h" #include "ARMBaseInstrInfo.h" +#include "ARMSubtarget.h" +#include "MCTargetDesc/ARMAddressingModes.h" #include "Thumb2InstrInfo.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/PostOrderIterator.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineInstr.h" #include "llvm/CodeGen/MachineInstrBuilder.h" -#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/IR/Function.h" // To access Function attributes #include "llvm/Support/CommandLine.h" -#include "llvm/Support/Compiler.h" #include "llvm/Support/Debug.h" -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/Statistic.h" +#include "llvm/Target/TargetMachine.h" using namespace llvm; +#define DEBUG_TYPE "t2-reduce-size" + STATISTIC(NumNarrows, "Number of 32-bit instrs reduced to 16-bit ones"); STATISTIC(Num2Addrs, "Number of 32-bit instrs reduced to 2addr 16-bit ones"); STATISTIC(NumLdSts, "Number of 32-bit load / store reduced to 16-bit ones"); @@ -38,92 +41,105 @@ namespace { /// ReduceTable - A static table with information on mapping from wide /// opcodes to narrow struct ReduceEntry { - unsigned WideOpc; // Wide opcode - unsigned NarrowOpc1; // Narrow opcode to transform to - unsigned NarrowOpc2; // Narrow opcode when it's two-address + uint16_t WideOpc; // Wide opcode + uint16_t NarrowOpc1; // Narrow opcode to transform to + uint16_t NarrowOpc2; // Narrow opcode when it's two-address uint8_t Imm1Limit; // Limit of immediate field (bits) uint8_t Imm2Limit; // Limit of immediate field when it's two-address unsigned LowRegs1 : 1; // Only possible if low-registers are used unsigned LowRegs2 : 1; // Only possible if low-registers are used (2addr) - unsigned PredCC1 : 1; // 0 - If predicated, cc is on and vice versa. + unsigned PredCC1 : 2; // 0 - If predicated, cc is on and vice versa. // 1 - No cc field. - unsigned PredCC2 : 1; + // 2 - Always set CPSR. + unsigned PredCC2 : 2; + unsigned PartFlag : 1; // 16-bit instruction does partial flag update unsigned Special : 1; // Needs to be dealt with specially + unsigned AvoidMovs: 1; // Avoid movs with shifter operand (for Swift) }; static const ReduceEntry ReduceTable[] = { - // Wide, Narrow1, Narrow2, imm1,imm2, lo1, lo2, P/C, S - { ARM::t2ADCrr, ARM::tADC, 0, 0, 0, 1, 0, 0,0, 0 }, - // FIXME: t2ADDS variants. - { ARM::t2ADDri, ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 0,0, 0 }, - { ARM::t2ADDrr, ARM::tADDrr, ARM::tADDhirr, 0, 0, 1, 0, 0,1, 0 }, - { ARM::t2ANDrr, 0, ARM::tAND, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2ASRri, ARM::tASRri, 0, 5, 0, 1, 0, 0,0, 0 }, - { ARM::t2ASRrr, 0, ARM::tASRrr, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2BICrr, 0, ARM::tBIC, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2CMNrr, ARM::tCMN, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2CMPri, ARM::tCMPi8, 0, 8, 0, 1, 0, 1,0, 0 }, - { ARM::t2CMPrr, ARM::tCMPhir, 0, 0, 0, 0, 0, 1,0, 0 }, - { ARM::t2CMPzri,ARM::tCMPzi8, 0, 8, 0, 1, 0, 1,0, 0 }, - { ARM::t2CMPzrr,ARM::tCMPzhir,0, 0, 0, 0, 0, 1,0, 0 }, - { ARM::t2EORrr, 0, ARM::tEOR, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2LSLri, ARM::tLSLri, 0, 5, 0, 1, 0, 0,0, 0 }, - { ARM::t2LSLrr, 0, ARM::tLSLrr, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2LSRri, ARM::tLSRri, 0, 5, 0, 1, 0, 0,0, 0 }, - { ARM::t2LSRrr, 0, ARM::tLSRrr, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2MOVi, ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 0 }, - // FIXME: Do we need the 16-bit 'S' variant? - // FIXME: t2MOVcc - { ARM::t2MOVr,ARM::tMOVgpr2gpr,0, 0, 0, 0, 0, 1,0, 0 }, - { ARM::t2MUL, 0, ARM::tMUL, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2MVNr, ARM::tMVN, 0, 0, 0, 1, 0, 0,0, 0 }, - { ARM::t2ORRrr, 0, ARM::tORR, 0, 0, 0, 1, 0,0, 0 }, - { ARM::t2REV, ARM::tREV, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2REV16, ARM::tREV16, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2REVSH, ARM::tREVSH, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2RORrr, 0, ARM::tROR, 0, 0, 0, 1, 0,0, 0 }, - // FIXME: T2RSBri immediate must be zero. Also need entry for T2RSBS - //{ ARM::t2RSBri, ARM::tRSB, 0, 0, 0, 1, 0, 0,0, 0 }, - { ARM::t2SUBri, ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 0,0, 0 }, - { ARM::t2SUBrr, ARM::tSUBrr, 0, 0, 0, 1, 0, 0,0, 0 }, - { ARM::t2SXTBr, ARM::tSXTB, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2SXTHr, ARM::tSXTH, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2TSTrr, ARM::tTST, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2UXTBr, ARM::tUXTB, 0, 0, 0, 1, 0, 1,0, 0 }, - { ARM::t2UXTHr, ARM::tUXTH, 0, 0, 0, 1, 0, 1,0, 0 }, - - // FIXME: Clean this up after splitting each Thumb load / store opcode - // into multiple ones. - { ARM::t2LDRi12,ARM::tLDR, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRs, ARM::tLDR, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRBi12,ARM::tLDRB, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRBs, ARM::tLDRB, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRHi12,ARM::tLDRH, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRHs, ARM::tLDRH, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRSBs,ARM::tLDRSB, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRSHs,ARM::tLDRSH, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRi12,ARM::tSTR, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRs, ARM::tSTR, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRBi12,ARM::tSTRB, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRBs, ARM::tSTRB, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRHi12,ARM::tSTRH, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRHs, ARM::tSTRH, 0, 0, 0, 1, 0, 0,0, 1 }, - - { ARM::t2LDM_RET,0, ARM::tPOP_RET, 0, 0, 1, 1, 1,1, 1 }, - { ARM::t2LDM, ARM::tLDM, ARM::tPOP, 0, 0, 1, 1, 1,1, 1 }, - { ARM::t2STM, ARM::tSTM, ARM::tPUSH, 0, 0, 1, 1, 1,1, 1 }, + // Wide, Narrow1, Narrow2, imm1,imm2, lo1, lo2, P/C,PF,S,AM + { ARM::t2ADCrr, 0, ARM::tADC, 0, 0, 0, 1, 0,0, 0,0,0 }, + { ARM::t2ADDri, ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 0,0, 0,1,0 }, + { ARM::t2ADDrr, ARM::tADDrr, ARM::tADDhirr, 0, 0, 1, 0, 0,1, 0,0,0 }, + { ARM::t2ADDSri,ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 2,2, 0,1,0 }, + { ARM::t2ADDSrr,ARM::tADDrr, 0, 0, 0, 1, 0, 2,0, 0,1,0 }, + { ARM::t2ANDrr, 0, ARM::tAND, 0, 0, 0, 1, 0,0, 1,0,0 }, + { ARM::t2ASRri, ARM::tASRri, 0, 5, 0, 1, 0, 0,0, 1,0,1 }, + { ARM::t2ASRrr, 0, ARM::tASRrr, 0, 0, 0, 1, 0,0, 1,0,1 }, + { ARM::t2BICrr, 0, ARM::tBIC, 0, 0, 0, 1, 0,0, 1,0,0 }, + //FIXME: Disable CMN, as CCodes are backwards from compare expectations + //{ ARM::t2CMNrr, ARM::tCMN, 0, 0, 0, 1, 0, 2,0, 0,0,0 }, + { ARM::t2CMNzrr, ARM::tCMNz, 0, 0, 0, 1, 0, 2,0, 0,0,0 }, + { ARM::t2CMPri, ARM::tCMPi8, 0, 8, 0, 1, 0, 2,0, 0,0,0 }, + { ARM::t2CMPrr, ARM::tCMPhir, 0, 0, 0, 0, 0, 2,0, 0,1,0 }, + { ARM::t2EORrr, 0, ARM::tEOR, 0, 0, 0, 1, 0,0, 1,0,0 }, + // FIXME: adr.n immediate offset must be multiple of 4. + //{ ARM::t2LEApcrelJT,ARM::tLEApcrelJT, 0, 0, 0, 1, 0, 1,0, 0,0,0 }, + { ARM::t2LSLri, ARM::tLSLri, 0, 5, 0, 1, 0, 0,0, 1,0,1 }, + { ARM::t2LSLrr, 0, ARM::tLSLrr, 0, 0, 0, 1, 0,0, 1,0,1 }, + { ARM::t2LSRri, ARM::tLSRri, 0, 5, 0, 1, 0, 0,0, 1,0,1 }, + { ARM::t2LSRrr, 0, ARM::tLSRrr, 0, 0, 0, 1, 0,0, 1,0,1 }, + { ARM::t2MOVi, ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 1,0,0 }, + { ARM::t2MOVi16,ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 1,1,0 }, + // FIXME: Do we need the 16-bit 'S' variant? + { ARM::t2MOVr,ARM::tMOVr, 0, 0, 0, 0, 0, 1,0, 0,0,0 }, + { ARM::t2MUL, 0, ARM::tMUL, 0, 0, 0, 1, 0,0, 1,0,0 }, + { ARM::t2MVNr, ARM::tMVN, 0, 0, 0, 1, 0, 0,0, 0,0,0 }, + { ARM::t2ORRrr, 0, ARM::tORR, 0, 0, 0, 1, 0,0, 1,0,0 }, + { ARM::t2REV, ARM::tREV, 0, 0, 0, 1, 0, 1,0, 0,0,0 }, + { ARM::t2REV16, ARM::tREV16, 0, 0, 0, 1, 0, 1,0, 0,0,0 }, + { ARM::t2REVSH, ARM::tREVSH, 0, 0, 0, 1, 0, 1,0, 0,0,0 }, + { ARM::t2RORrr, 0, ARM::tROR, 0, 0, 0, 1, 0,0, 1,0,0 }, + { ARM::t2RSBri, ARM::tRSB, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2RSBSri,ARM::tRSB, 0, 0, 0, 1, 0, 2,0, 0,1,0 }, + { ARM::t2SBCrr, 0, ARM::tSBC, 0, 0, 0, 1, 0,0, 0,0,0 }, + { ARM::t2SUBri, ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 0,0, 0,0,0 }, + { ARM::t2SUBrr, ARM::tSUBrr, 0, 0, 0, 1, 0, 0,0, 0,0,0 }, + { ARM::t2SUBSri,ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 2,2, 0,0,0 }, + { ARM::t2SUBSrr,ARM::tSUBrr, 0, 0, 0, 1, 0, 2,0, 0,0,0 }, + { ARM::t2SXTB, ARM::tSXTB, 0, 0, 0, 1, 0, 1,0, 0,1,0 }, + { ARM::t2SXTH, ARM::tSXTH, 0, 0, 0, 1, 0, 1,0, 0,1,0 }, + { ARM::t2TSTrr, ARM::tTST, 0, 0, 0, 1, 0, 2,0, 0,0,0 }, + { ARM::t2UXTB, ARM::tUXTB, 0, 0, 0, 1, 0, 1,0, 0,1,0 }, + { ARM::t2UXTH, ARM::tUXTH, 0, 0, 0, 1, 0, 1,0, 0,1,0 }, + + // FIXME: Clean this up after splitting each Thumb load / store opcode + // into multiple ones. + { ARM::t2LDRi12,ARM::tLDRi, ARM::tLDRspi, 5, 8, 1, 0, 0,0, 0,1,0 }, + { ARM::t2LDRs, ARM::tLDRr, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2LDRBi12,ARM::tLDRBi, 0, 5, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2LDRBs, ARM::tLDRBr, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2LDRHi12,ARM::tLDRHi, 0, 5, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2LDRHs, ARM::tLDRHr, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2LDRSBs,ARM::tLDRSB, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2LDRSHs,ARM::tLDRSH, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2STRi12,ARM::tSTRi, ARM::tSTRspi, 5, 8, 1, 0, 0,0, 0,1,0 }, + { ARM::t2STRs, ARM::tSTRr, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2STRBi12,ARM::tSTRBi, 0, 5, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2STRBs, ARM::tSTRBr, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2STRHi12,ARM::tSTRHi, 0, 5, 0, 1, 0, 0,0, 0,1,0 }, + { ARM::t2STRHs, ARM::tSTRHr, 0, 0, 0, 1, 0, 0,0, 0,1,0 }, + + { ARM::t2LDMIA, ARM::tLDMIA, 0, 0, 0, 1, 1, 1,1, 0,1,0 }, + { ARM::t2LDMIA_RET,0, ARM::tPOP_RET, 0, 0, 1, 1, 1,1, 0,1,0 }, + { ARM::t2LDMIA_UPD,ARM::tLDMIA_UPD,ARM::tPOP,0, 0, 1, 1, 1,1, 0,1,0 }, + // ARM::t2STM (with no basereg writeback) has no Thumb1 equivalent + { ARM::t2STMIA_UPD,ARM::tSTMIA_UPD, 0, 0, 0, 1, 1, 1,1, 0,1,0 }, + { ARM::t2STMDB_UPD, 0, ARM::tPUSH, 0, 0, 1, 1, 1,1, 0,1,0 } }; - class VISIBILITY_HIDDEN Thumb2SizeReduce : public MachineFunctionPass { + class Thumb2SizeReduce : public MachineFunctionPass { public: static char ID; Thumb2SizeReduce(); - const TargetInstrInfo *TII; + const Thumb2InstrInfo *TII; + const ARMSubtarget *STI; - virtual bool runOnMachineFunction(MachineFunction &MF); + bool runOnMachineFunction(MachineFunction &MF) override; - virtual const char *getPassName() const { + const char *getPassName() const override { return "Thumb2 instruction size reduction pass"; } @@ -131,31 +147,62 @@ namespace { /// ReduceOpcodeMap - Maps wide opcode to index of entry in ReduceTable. DenseMap ReduceOpcodeMap; + bool canAddPseudoFlagDep(MachineInstr *Use, bool IsSelfLoop); + + bool VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry, + bool is2Addr, ARMCC::CondCodes Pred, + bool LiveCPSR, bool &HasCC, bool &CCDead); + bool ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry); bool ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, - const ReduceEntry &Entry, bool LiveCPSR); + const ReduceEntry &Entry, bool LiveCPSR, bool IsSelfLoop); /// ReduceTo2Addr - Reduce a 32-bit instruction to a 16-bit two-address /// instruction. bool ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, - const ReduceEntry &Entry, - bool LiveCPSR); + const ReduceEntry &Entry, bool LiveCPSR, + bool IsSelfLoop); /// ReduceToNarrow - Reduce a 32-bit instruction to a 16-bit /// non-two-address instruction. bool ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI, - const ReduceEntry &Entry, - bool LiveCPSR); + const ReduceEntry &Entry, bool LiveCPSR, + bool IsSelfLoop); + + /// ReduceMI - Attempt to reduce MI, return true on success. + bool ReduceMI(MachineBasicBlock &MBB, MachineInstr *MI, + bool LiveCPSR, bool IsSelfLoop); /// ReduceMBB - Reduce width of instructions in the specified basic block. bool ReduceMBB(MachineBasicBlock &MBB); + + bool OptimizeSize; + bool MinimizeSize; + + // Last instruction to define CPSR in the current block. + MachineInstr *CPSRDef; + // Was CPSR last defined by a high latency instruction? + // When CPSRDef is null, this refers to CPSR defs in predecessors. + bool HighLatencyCPSR; + + struct MBBInfo { + // The flags leaving this block have high latency. + bool HighLatencyCPSR; + // Has this block been visited yet? + bool Visited; + + MBBInfo() : HighLatencyCPSR(false), Visited(false) {} + }; + + SmallVector BlockInfo; }; char Thumb2SizeReduce::ID = 0; } -Thumb2SizeReduce::Thumb2SizeReduce() : MachineFunctionPass(&ID) { +Thumb2SizeReduce::Thumb2SizeReduce() : MachineFunctionPass(ID) { + OptimizeSize = MinimizeSize = false; for (unsigned i = 0, e = array_lengthof(ReduceTable); i != e; ++i) { unsigned FromOpc = ReduceTable[i].WideOpc; if (!ReduceOpcodeMap.insert(std::make_pair(FromOpc, i)).second) @@ -163,9 +210,87 @@ Thumb2SizeReduce::Thumb2SizeReduce() : MachineFunctionPass(&ID) { } } -static bool VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry, - bool is2Addr, ARMCC::CondCodes Pred, - bool LiveCPSR, bool &HasCC, bool &CCDead) { +static bool HasImplicitCPSRDef(const MCInstrDesc &MCID) { + for (const uint16_t *Regs = MCID.getImplicitDefs(); *Regs; ++Regs) + if (*Regs == ARM::CPSR) + return true; + return false; +} + +// Check for a likely high-latency flag def. +static bool isHighLatencyCPSR(MachineInstr *Def) { + switch(Def->getOpcode()) { + case ARM::FMSTAT: + case ARM::tMUL: + return true; + } + return false; +} + +/// canAddPseudoFlagDep - For A9 (and other out-of-order) implementations, +/// the 's' 16-bit instruction partially update CPSR. Abort the +/// transformation to avoid adding false dependency on last CPSR setting +/// instruction which hurts the ability for out-of-order execution engine +/// to do register renaming magic. +/// This function checks if there is a read-of-write dependency between the +/// last instruction that defines the CPSR and the current instruction. If there +/// is, then there is no harm done since the instruction cannot be retired +/// before the CPSR setting instruction anyway. +/// Note, we are not doing full dependency analysis here for the sake of compile +/// time. We're not looking for cases like: +/// r0 = muls ... +/// r1 = add.w r0, ... +/// ... +/// = mul.w r1 +/// In this case it would have been ok to narrow the mul.w to muls since there +/// are indirect RAW dependency between the muls and the mul.w +bool +Thumb2SizeReduce::canAddPseudoFlagDep(MachineInstr *Use, bool FirstInSelfLoop) { + // Disable the check for -Oz (aka OptimizeForSizeHarder). + if (MinimizeSize || !STI->avoidCPSRPartialUpdate()) + return false; + + if (!CPSRDef) + // If this BB loops back to itself, conservatively avoid narrowing the + // first instruction that does partial flag update. + return HighLatencyCPSR || FirstInSelfLoop; + + SmallSet Defs; + for (const MachineOperand &MO : CPSRDef->operands()) { + if (!MO.isReg() || MO.isUndef() || MO.isUse()) + continue; + unsigned Reg = MO.getReg(); + if (Reg == 0 || Reg == ARM::CPSR) + continue; + Defs.insert(Reg); + } + + for (const MachineOperand &MO : Use->operands()) { + if (!MO.isReg() || MO.isUndef() || MO.isDef()) + continue; + unsigned Reg = MO.getReg(); + if (Defs.count(Reg)) + return false; + } + + // If the current CPSR has high latency, try to avoid the false dependency. + if (HighLatencyCPSR) + return true; + + // tMOVi8 usually doesn't start long dependency chains, and there are a lot + // of them, so always shrink them when CPSR doesn't have high latency. + if (Use->getOpcode() == ARM::t2MOVi || + Use->getOpcode() == ARM::t2MOVi16) + return false; + + // No read-after-write dependency. The narrowing will add false dependency. + return true; +} + +bool +Thumb2SizeReduce::VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry, + bool is2Addr, ARMCC::CondCodes Pred, + bool LiveCPSR, bool &HasCC, bool &CCDead) { if ((is2Addr && Entry.PredCC2 == 0) || (!is2Addr && Entry.PredCC1 == 0)) { if (Pred == ARMCC::AL) { @@ -186,6 +311,16 @@ static bool VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry, if (HasCC) return false; } + } else if ((is2Addr && Entry.PredCC2 == 2) || + (!is2Addr && Entry.PredCC1 == 2)) { + /// Old opcode has an optional def of CPSR. + if (HasCC) + return true; + // If old opcode does not implicitly define CPSR, then it's not ok since + // these new opcodes' CPSR def is not meant to be thrown away. e.g. CMP. + if (!HasImplicitCPSRDef(MI->getDesc())) + return false; + HasCC = true; } else { // 16-bit instruction does not set CPSR. if (HasCC) @@ -197,8 +332,10 @@ static bool VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry, static bool VerifyLowRegs(MachineInstr *MI) { unsigned Opc = MI->getOpcode(); - bool isPCOk = (Opc == ARM::t2LDM_RET) || (Opc == ARM::t2LDM); - bool isLROk = (Opc == ARM::t2STM); + bool isPCOk = (Opc == ARM::t2LDMIA_RET || Opc == ARM::t2LDMIA || + Opc == ARM::t2LDMDB || Opc == ARM::t2LDMIA_UPD || + Opc == ARM::t2LDMDB_UPD); + bool isLROk = (Opc == ARM::t2STMIA_UPD || Opc == ARM::t2STMDB_UPD); bool isSPOk = isPCOk || isLROk; for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { const MachineOperand &MO = MI->getOperand(i); @@ -211,8 +348,13 @@ static bool VerifyLowRegs(MachineInstr *MI) { continue; if (isLROk && Reg == ARM::LR) continue; - if (isSPOk && Reg == ARM::SP) - continue; + if (Reg == ARM::SP) { + if (isSPOk) + continue; + if (i == 1 && (Opc == ARM::t2LDRi12 || Opc == ARM::t2STRi12)) + // Special case for these ldr / str with sp as base register. + continue; + } if (!isARMLowRegister(Reg)) return false; } @@ -228,26 +370,37 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI, unsigned Scale = 1; bool HasImmOffset = false; bool HasShift = false; + bool HasOffReg = true; bool isLdStMul = false; - bool isPopPush = false; unsigned Opc = Entry.NarrowOpc1; unsigned OpNum = 3; // First 'rest' of operands. + uint8_t ImmLimit = Entry.Imm1Limit; + switch (Entry.WideOpc) { default: llvm_unreachable("Unexpected Thumb2 load / store opcode!"); case ARM::t2LDRi12: case ARM::t2STRi12: + if (MI->getOperand(1).getReg() == ARM::SP) { + Opc = Entry.NarrowOpc2; + ImmLimit = Entry.Imm2Limit; + HasOffReg = false; + } + Scale = 4; HasImmOffset = true; + HasOffReg = false; break; case ARM::t2LDRBi12: case ARM::t2STRBi12: HasImmOffset = true; + HasOffReg = false; break; case ARM::t2LDRHi12: case ARM::t2STRHi12: Scale = 2; HasImmOffset = true; + HasOffReg = false; break; case ARM::t2LDRs: case ARM::t2LDRBs: @@ -260,22 +413,56 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI, HasShift = true; OpNum = 4; break; - case ARM::t2LDM_RET: - case ARM::t2LDM: - case ARM::t2STM: { - OpNum = 0; + case ARM::t2LDMIA: + case ARM::t2LDMDB: { unsigned BaseReg = MI->getOperand(0).getReg(); - unsigned Mode = MI->getOperand(1).getImm(); - if (BaseReg == ARM::SP && ARM_AM::getAM4WBFlag(Mode)) { - Opc = Entry.NarrowOpc2; - isPopPush = true; + if (!isARMLowRegister(BaseReg) || Entry.WideOpc != ARM::t2LDMIA) + return false; + + // For the non-writeback version (this one), the base register must be + // one of the registers being loaded. + bool isOK = false; + for (unsigned i = 4; i < MI->getNumOperands(); ++i) { + if (MI->getOperand(i).getReg() == BaseReg) { + isOK = true; + break; + } + } + + if (!isOK) + return false; + + OpNum = 0; + isLdStMul = true; + break; + } + case ARM::t2LDMIA_RET: { + unsigned BaseReg = MI->getOperand(1).getReg(); + if (BaseReg != ARM::SP) + return false; + Opc = Entry.NarrowOpc2; // tPOP_RET + OpNum = 2; + isLdStMul = true; + break; + } + case ARM::t2LDMIA_UPD: + case ARM::t2LDMDB_UPD: + case ARM::t2STMIA_UPD: + case ARM::t2STMDB_UPD: { + OpNum = 0; + + unsigned BaseReg = MI->getOperand(1).getReg(); + if (BaseReg == ARM::SP && + (Entry.WideOpc == ARM::t2LDMIA_UPD || + Entry.WideOpc == ARM::t2STMDB_UPD)) { + Opc = Entry.NarrowOpc2; // tPOP or tPUSH OpNum = 2; - } else if (Entry.WideOpc == ARM::t2LDM_RET || - !isARMLowRegister(BaseReg) || - !ARM_AM::getAM4WBFlag(Mode) || - ARM_AM::getAM4SubMode(Mode) != ARM_AM::ia) { + } else if (!isARMLowRegister(BaseReg) || + (Entry.WideOpc != ARM::t2LDMIA_UPD && + Entry.WideOpc != ARM::t2STMIA_UPD)) { return false; } + isLdStMul = true; break; } @@ -286,6 +473,7 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI, if (HasShift) { OffsetReg = MI->getOperand(2).getReg(); OffsetKill = MI->getOperand(2).isKill(); + if (MI->getOperand(3).getImm()) // Thumb1 addressing mode doesn't support shift. return false; @@ -294,36 +482,42 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI, unsigned OffsetImm = 0; if (HasImmOffset) { OffsetImm = MI->getOperand(2).getImm(); - unsigned MaxOffset = ((1 << Entry.Imm1Limit) - 1) * Scale; - if ((OffsetImm & (Scale-1)) || OffsetImm > MaxOffset) + unsigned MaxOffset = ((1 << ImmLimit) - 1) * Scale; + + if ((OffsetImm & (Scale - 1)) || OffsetImm > MaxOffset) // Make sure the immediate field fits. return false; } // Add the 16-bit load / store instruction. - // FIXME: Thumb1 addressing mode encode both immediate and register offset. DebugLoc dl = MI->getDebugLoc(); - MachineInstrBuilder MIB = BuildMI(MBB, *MI, dl, TII->get(Opc)); + MachineInstrBuilder MIB = BuildMI(MBB, MI, dl, TII->get(Opc)); if (!isLdStMul) { - MIB.addOperand(MI->getOperand(0)).addOperand(MI->getOperand(1)); - if (Entry.NarrowOpc1 != ARM::tLDRSB && Entry.NarrowOpc1 != ARM::tLDRSH) { - // tLDRSB and tLDRSH do not have an immediate offset field. On the other - // hand, it must have an offset register. - // FIXME: Remove this special case. - MIB.addImm(OffsetImm/Scale); - } + MIB.addOperand(MI->getOperand(0)); + MIB.addOperand(MI->getOperand(1)); + + if (HasImmOffset) + MIB.addImm(OffsetImm / Scale); + assert((!HasShift || OffsetReg) && "Invalid so_reg load / store address!"); - MIB.addReg(OffsetReg, getKillRegState(OffsetKill)); + if (HasOffReg) + MIB.addReg(OffsetReg, getKillRegState(OffsetKill)); } // Transfer the rest of operands. for (unsigned e = MI->getNumOperands(); OpNum != e; ++OpNum) MIB.addOperand(MI->getOperand(OpNum)); - DOUT << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB; + // Transfer memoperands. + MIB->setMemRefs(MI->memoperands_begin(), MI->memoperands_end()); + + // Transfer MI flags. + MIB.setMIFlags(MI->getFlags()); - MBB.erase(MI); + DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB); + + MBB.erase_instr(MI); ++NumLdSts; return true; } @@ -331,29 +525,148 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI, bool Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry, - bool LiveCPSR) { + bool LiveCPSR, bool IsSelfLoop) { + unsigned Opc = MI->getOpcode(); + if (Opc == ARM::t2ADDri) { + // If the source register is SP, try to reduce to tADDrSPi, otherwise + // it's a normal reduce. + if (MI->getOperand(1).getReg() != ARM::SP) { + if (ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, IsSelfLoop)) + return true; + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop); + } + // Try to reduce to tADDrSPi. + unsigned Imm = MI->getOperand(2).getImm(); + // The immediate must be in range, the destination register must be a low + // reg, the predicate must be "always" and the condition flags must not + // be being set. + if (Imm & 3 || Imm > 1020) + return false; + if (!isARMLowRegister(MI->getOperand(0).getReg())) + return false; + if (MI->getOperand(3).getImm() != ARMCC::AL) + return false; + const MCInstrDesc &MCID = MI->getDesc(); + if (MCID.hasOptionalDef() && + MI->getOperand(MCID.getNumOperands()-1).getReg() == ARM::CPSR) + return false; + + MachineInstrBuilder MIB = BuildMI(MBB, MI, MI->getDebugLoc(), + TII->get(ARM::tADDrSPi)) + .addOperand(MI->getOperand(0)) + .addOperand(MI->getOperand(1)) + .addImm(Imm / 4); // The tADDrSPi has an implied scale by four. + AddDefaultPred(MIB); + + // Transfer MI flags. + MIB.setMIFlags(MI->getFlags()); + + DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " <<*MIB); + + MBB.erase_instr(MI); + ++NumNarrows; + return true; + } + if (Entry.LowRegs1 && !VerifyLowRegs(MI)) return false; - const TargetInstrDesc &TID = MI->getDesc(); - if (TID.mayLoad() || TID.mayStore()) + if (MI->mayLoad() || MI->mayStore()) return ReduceLoadStore(MBB, MI, Entry); + + switch (Opc) { + default: break; + case ARM::t2ADDSri: + case ARM::t2ADDSrr: { + unsigned PredReg = 0; + if (getInstrPredicate(MI, PredReg) == ARMCC::AL) { + switch (Opc) { + default: break; + case ARM::t2ADDSri: { + if (ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, IsSelfLoop)) + return true; + // fallthrough + } + case ARM::t2ADDSrr: + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop); + } + } + break; + } + case ARM::t2RSBri: + case ARM::t2RSBSri: + case ARM::t2SXTB: + case ARM::t2SXTH: + case ARM::t2UXTB: + case ARM::t2UXTH: + if (MI->getOperand(2).getImm() == 0) + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop); + break; + case ARM::t2MOVi16: + // Can convert only 'pure' immediate operands, not immediates obtained as + // globals' addresses. + if (MI->getOperand(1).isImm()) + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop); + break; + case ARM::t2CMPrr: { + // Try to reduce to the lo-reg only version first. Why there are two + // versions of the instruction is a mystery. + // It would be nice to just have two entries in the master table that + // are prioritized, but the table assumes a unique entry for each + // source insn opcode. So for now, we hack a local entry record to use. + static const ReduceEntry NarrowEntry = + { ARM::t2CMPrr,ARM::tCMPr, 0, 0, 0, 1, 1,2, 0, 0,1,0 }; + if (ReduceToNarrow(MBB, MI, NarrowEntry, LiveCPSR, IsSelfLoop)) + return true; + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop); + } + } return false; } bool Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry, - bool LiveCPSR) { + bool LiveCPSR, bool IsSelfLoop) { if (ReduceLimit2Addr != -1 && ((int)Num2Addrs >= ReduceLimit2Addr)) return false; - const TargetInstrDesc &TID = MI->getDesc(); + if (!MinimizeSize && !OptimizeSize && Entry.AvoidMovs && + STI->avoidMOVsShifterOperand()) + // Don't issue movs with shifter operand for some CPUs unless we + // are optimizing / minimizing for size. + return false; + unsigned Reg0 = MI->getOperand(0).getReg(); unsigned Reg1 = MI->getOperand(1).getReg(); - if (Reg0 != Reg1) - return false; + // t2MUL is "special". The tied source operand is second, not first. + if (MI->getOpcode() == ARM::t2MUL) { + unsigned Reg2 = MI->getOperand(2).getReg(); + // Early exit if the regs aren't all low regs. + if (!isARMLowRegister(Reg0) || !isARMLowRegister(Reg1) + || !isARMLowRegister(Reg2)) + return false; + if (Reg0 != Reg2) { + // If the other operand also isn't the same as the destination, we + // can't reduce. + if (Reg1 != Reg0) + return false; + // Try to commute the operands to make it a 2-address instruction. + MachineInstr *CommutedMI = TII->commuteInstruction(MI); + if (!CommutedMI) + return false; + } + } else if (Reg0 != Reg1) { + // Try to commute the operands to make it a 2-address instruction. + unsigned CommOpIdx1, CommOpIdx2; + if (!TII->findCommutedOpIndices(MI, CommOpIdx1, CommOpIdx2) || + CommOpIdx1 != 1 || MI->getOperand(CommOpIdx2).getReg() != Reg0) + return false; + MachineInstr *CommutedMI = TII->commuteInstruction(MI); + if (!CommutedMI) + return false; + } if (Entry.LowRegs2 && !isARMLowRegister(Reg0)) return false; if (Entry.Imm2Limit) { @@ -368,22 +681,23 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, } // Check if it's possible / necessary to transfer the predicate. - const TargetInstrDesc &NewTID = TII->get(Entry.NarrowOpc2); + const MCInstrDesc &NewMCID = TII->get(Entry.NarrowOpc2); unsigned PredReg = 0; ARMCC::CondCodes Pred = getInstrPredicate(MI, PredReg); bool SkipPred = false; if (Pred != ARMCC::AL) { - if (!NewTID.isPredicable()) + if (!NewMCID.isPredicable()) // Can't transfer predicate, fail. return false; } else { - SkipPred = !NewTID.isPredicable(); + SkipPred = !NewMCID.isPredicable(); } bool HasCC = false; bool CCDead = false; - if (TID.hasOptionalDef()) { - unsigned NumOps = TID.getNumOperands(); + const MCInstrDesc &MCID = MI->getDesc(); + if (MCID.hasOptionalDef()) { + unsigned NumOps = MCID.getNumOperands(); HasCC = (MI->getOperand(NumOps-1).getReg() == ARM::CPSR); if (HasCC && MI->getOperand(NumOps-1).isDead()) CCDead = true; @@ -391,26 +705,39 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, if (!VerifyPredAndCC(MI, Entry, true, Pred, LiveCPSR, HasCC, CCDead)) return false; + // Avoid adding a false dependency on partial flag update by some 16-bit + // instructions which has the 's' bit set. + if (Entry.PartFlag && NewMCID.hasOptionalDef() && HasCC && + canAddPseudoFlagDep(MI, IsSelfLoop)) + return false; + // Add the 16-bit instruction. DebugLoc dl = MI->getDebugLoc(); - MachineInstrBuilder MIB = BuildMI(MBB, *MI, dl, TII->get(Entry.NarrowOpc2)); + MachineInstrBuilder MIB = BuildMI(MBB, MI, dl, NewMCID); MIB.addOperand(MI->getOperand(0)); - if (HasCC) - AddDefaultT1CC(MIB, CCDead); + if (NewMCID.hasOptionalDef()) { + if (HasCC) + AddDefaultT1CC(MIB, CCDead); + else + AddNoT1CC(MIB); + } // Transfer the rest of operands. - unsigned NumOps = TID.getNumOperands(); + unsigned NumOps = MCID.getNumOperands(); for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i) { - if (i < NumOps && TID.OpInfo[i].isOptionalDef()) + if (i < NumOps && MCID.OpInfo[i].isOptionalDef()) continue; - if (SkipPred && TID.OpInfo[i].isPredicate()) + if (SkipPred && MCID.OpInfo[i].isPredicate()) continue; MIB.addOperand(MI->getOperand(i)); } - DOUT << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB; + // Transfer MI flags. + MIB.setMIFlags(MI->getFlags()); + + DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB); - MBB.erase(MI); + MBB.erase_instr(MI); ++Num2Addrs; return true; } @@ -418,17 +745,23 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, bool Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry, - bool LiveCPSR) { + bool LiveCPSR, bool IsSelfLoop) { if (ReduceLimit != -1 && ((int)NumNarrows >= ReduceLimit)) return false; + if (!MinimizeSize && !OptimizeSize && Entry.AvoidMovs && + STI->avoidMOVsShifterOperand()) + // Don't issue movs with shifter operand for some CPUs unless we + // are optimizing / minimizing for size. + return false; + unsigned Limit = ~0U; if (Entry.Imm1Limit) Limit = (1 << Entry.Imm1Limit) - 1; - const TargetInstrDesc &TID = MI->getDesc(); - for (unsigned i = 0, e = TID.getNumOperands(); i != e; ++i) { - if (TID.OpInfo[i].isPredicate()) + const MCInstrDesc &MCID = MI->getDesc(); + for (unsigned i = 0, e = MCID.getNumOperands(); i != e; ++i) { + if (MCID.OpInfo[i].isPredicate()) continue; const MachineOperand &MO = MI->getOperand(i); if (MO.isReg()) { @@ -437,29 +770,30 @@ Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI, continue; if (Entry.LowRegs1 && !isARMLowRegister(Reg)) return false; - } else if (MO.isImm()) { - if (MO.getImm() > Limit) + } else if (MO.isImm() && + !MCID.OpInfo[i].isPredicate()) { + if (((unsigned)MO.getImm()) > Limit) return false; } } // Check if it's possible / necessary to transfer the predicate. - const TargetInstrDesc &NewTID = TII->get(Entry.NarrowOpc1); + const MCInstrDesc &NewMCID = TII->get(Entry.NarrowOpc1); unsigned PredReg = 0; ARMCC::CondCodes Pred = getInstrPredicate(MI, PredReg); bool SkipPred = false; if (Pred != ARMCC::AL) { - if (!NewTID.isPredicable()) + if (!NewMCID.isPredicable()) // Can't transfer predicate, fail. return false; } else { - SkipPred = !NewTID.isPredicable(); + SkipPred = !NewMCID.isPredicable(); } bool HasCC = false; bool CCDead = false; - if (TID.hasOptionalDef()) { - unsigned NumOps = TID.getNumOperands(); + if (MCID.hasOptionalDef()) { + unsigned NumOps = MCID.getNumOperands(); HasCC = (MI->getOperand(NumOps-1).getReg() == ARM::CPSR); if (HasCC && MI->getOperand(NumOps-1).isDead()) CCDead = true; @@ -467,45 +801,81 @@ Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI, if (!VerifyPredAndCC(MI, Entry, false, Pred, LiveCPSR, HasCC, CCDead)) return false; + // Avoid adding a false dependency on partial flag update by some 16-bit + // instructions which has the 's' bit set. + if (Entry.PartFlag && NewMCID.hasOptionalDef() && HasCC && + canAddPseudoFlagDep(MI, IsSelfLoop)) + return false; + // Add the 16-bit instruction. DebugLoc dl = MI->getDebugLoc(); - MachineInstrBuilder MIB = BuildMI(MBB, *MI, dl, TII->get(Entry.NarrowOpc1)); + MachineInstrBuilder MIB = BuildMI(MBB, MI, dl, NewMCID); MIB.addOperand(MI->getOperand(0)); - if (HasCC) - AddDefaultT1CC(MIB, CCDead); + if (NewMCID.hasOptionalDef()) { + if (HasCC) + AddDefaultT1CC(MIB, CCDead); + else + AddNoT1CC(MIB); + } // Transfer the rest of operands. - unsigned NumOps = TID.getNumOperands(); + unsigned NumOps = MCID.getNumOperands(); for (unsigned i = 1, e = MI->getNumOperands(); i != e; ++i) { - if (i < NumOps && TID.OpInfo[i].isOptionalDef()) + if (i < NumOps && MCID.OpInfo[i].isOptionalDef()) continue; - if (SkipPred && TID.OpInfo[i].isPredicate()) + if ((MCID.getOpcode() == ARM::t2RSBSri || + MCID.getOpcode() == ARM::t2RSBri || + MCID.getOpcode() == ARM::t2SXTB || + MCID.getOpcode() == ARM::t2SXTH || + MCID.getOpcode() == ARM::t2UXTB || + MCID.getOpcode() == ARM::t2UXTH) && i == 2) + // Skip the zero immediate operand, it's now implicit. continue; - MIB.addOperand(MI->getOperand(i)); + bool isPred = (i < NumOps && MCID.OpInfo[i].isPredicate()); + if (SkipPred && isPred) + continue; + const MachineOperand &MO = MI->getOperand(i); + if (MO.isReg() && MO.isImplicit() && MO.getReg() == ARM::CPSR) + // Skip implicit def of CPSR. Either it's modeled as an optional + // def now or it's already an implicit def on the new instruction. + continue; + MIB.addOperand(MO); } + if (!MCID.isPredicable() && NewMCID.isPredicable()) + AddDefaultPred(MIB); + // Transfer MI flags. + MIB.setMIFlags(MI->getFlags()); - DOUT << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB; + DEBUG(errs() << "Converted 32-bit: " << *MI << " to 16-bit: " << *MIB); - MBB.erase(MI); + MBB.erase_instr(MI); ++NumNarrows; return true; } -static bool UpdateCPSRLiveness(MachineInstr &MI, bool LiveCPSR) { +static bool UpdateCPSRDef(MachineInstr &MI, bool LiveCPSR, bool &DefCPSR) { bool HasDef = false; - for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { - const MachineOperand &MO = MI.getOperand(i); - if (!MO.isReg() || MO.isUndef()) + for (const MachineOperand &MO : MI.operands()) { + if (!MO.isReg() || MO.isUndef() || MO.isUse()) continue; if (MO.getReg() != ARM::CPSR) continue; - if (MO.isDef()) { - if (!MO.isDead()) - HasDef = true; - continue; - } + DefCPSR = true; + if (!MO.isDead()) + HasDef = true; + } + + return HasDef || LiveCPSR; +} + +static bool UpdateCPSRUse(MachineInstr &MI, bool LiveCPSR) { + for (const MachineOperand &MO : MI.operands()) { + if (!MO.isReg() || MO.isUndef() || MO.isDef()) + continue; + if (MO.getReg() != ARM::CPSR) + continue; assert(LiveCPSR && "CPSR liveness tracking is wrong!"); if (MO.isKill()) { LiveCPSR = false; @@ -513,69 +883,147 @@ static bool UpdateCPSRLiveness(MachineInstr &MI, bool LiveCPSR) { } } - return HasDef || LiveCPSR; + return LiveCPSR; +} + +bool Thumb2SizeReduce::ReduceMI(MachineBasicBlock &MBB, MachineInstr *MI, + bool LiveCPSR, bool IsSelfLoop) { + unsigned Opcode = MI->getOpcode(); + DenseMap::iterator OPI = ReduceOpcodeMap.find(Opcode); + if (OPI == ReduceOpcodeMap.end()) + return false; + const ReduceEntry &Entry = ReduceTable[OPI->second]; + + // Don't attempt normal reductions on "special" cases for now. + if (Entry.Special) + return ReduceSpecial(MBB, MI, Entry, LiveCPSR, IsSelfLoop); + + // Try to transform to a 16-bit two-address instruction. + if (Entry.NarrowOpc2 && + ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, IsSelfLoop)) + return true; + + // Try to transform to a 16-bit non-two-address instruction. + if (Entry.NarrowOpc1 && + ReduceToNarrow(MBB, MI, Entry, LiveCPSR, IsSelfLoop)) + return true; + + return false; } bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) { bool Modified = false; - bool LiveCPSR = false; // Yes, CPSR could be livein. - for (MachineBasicBlock::const_livein_iterator I = MBB.livein_begin(), - E = MBB.livein_end(); I != E; ++I) { - if (*I == ARM::CPSR) { - LiveCPSR = true; + bool LiveCPSR = MBB.isLiveIn(ARM::CPSR); + MachineInstr *BundleMI = nullptr; + + CPSRDef = nullptr; + HighLatencyCPSR = false; + + // Check predecessors for the latest CPSRDef. + for (auto *Pred : MBB.predecessors()) { + const MBBInfo &PInfo = BlockInfo[Pred->getNumber()]; + if (!PInfo.Visited) { + // Since blocks are visited in RPO, this must be a back-edge. + continue; + } + if (PInfo.HighLatencyCPSR) { + HighLatencyCPSR = true; break; } } - MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end(); - MachineBasicBlock::iterator NextMII; + // If this BB loops back to itself, conservatively avoid narrowing the + // first instruction that does partial flag update. + bool IsSelfLoop = MBB.isSuccessor(&MBB); + MachineBasicBlock::instr_iterator MII = MBB.instr_begin(),E = MBB.instr_end(); + MachineBasicBlock::instr_iterator NextMII; for (; MII != E; MII = NextMII) { - NextMII = next(MII); + NextMII = std::next(MII); MachineInstr *MI = &*MII; - unsigned Opcode = MI->getOpcode(); - DenseMap::iterator OPI = ReduceOpcodeMap.find(Opcode); - if (OPI != ReduceOpcodeMap.end()) { - const ReduceEntry &Entry = ReduceTable[OPI->second]; - // Ignore "special" cases for now. - if (Entry.Special) { - if (ReduceSpecial(MBB, MI, Entry, LiveCPSR)) { - Modified = true; - MachineBasicBlock::iterator I = prior(NextMII); - MI = &*I; - } - goto ProcessNext; - } + if (MI->isBundle()) { + BundleMI = MI; + continue; + } + if (MI->isDebugValue()) + continue; - // Try to transform to a 16-bit two-address instruction. - if (Entry.NarrowOpc2 && ReduceTo2Addr(MBB, MI, Entry, LiveCPSR)) { - Modified = true; - MachineBasicBlock::iterator I = prior(NextMII); - MI = &*I; - goto ProcessNext; - } + LiveCPSR = UpdateCPSRUse(*MI, LiveCPSR); - // Try to transform ro a 16-bit non-two-address instruction. - if (Entry.NarrowOpc1 && ReduceToNarrow(MBB, MI, Entry, LiveCPSR)) - Modified = true; + // Does NextMII belong to the same bundle as MI? + bool NextInSameBundle = NextMII != E && NextMII->isBundledWithPred(); + + if (ReduceMI(MBB, MI, LiveCPSR, IsSelfLoop)) { + Modified = true; + MachineBasicBlock::instr_iterator I = std::prev(NextMII); + MI = &*I; + // Removing and reinserting the first instruction in a bundle will break + // up the bundle. Fix the bundling if it was broken. + if (NextInSameBundle && !NextMII->isBundledWithPred()) + NextMII->bundleWithPred(); + } + + if (!NextInSameBundle && MI->isInsideBundle()) { + // FIXME: Since post-ra scheduler operates on bundles, the CPSR kill + // marker is only on the BUNDLE instruction. Process the BUNDLE + // instruction as we finish with the bundled instruction to work around + // the inconsistency. + if (BundleMI->killsRegister(ARM::CPSR)) + LiveCPSR = false; + MachineOperand *MO = BundleMI->findRegisterDefOperand(ARM::CPSR); + if (MO && !MO->isDead()) + LiveCPSR = true; + MO = BundleMI->findRegisterUseOperand(ARM::CPSR); + if (MO && !MO->isKill()) + LiveCPSR = true; } - ProcessNext: - LiveCPSR = UpdateCPSRLiveness(*MI, LiveCPSR); + bool DefCPSR = false; + LiveCPSR = UpdateCPSRDef(*MI, LiveCPSR, DefCPSR); + if (MI->isCall()) { + // Calls don't really set CPSR. + CPSRDef = nullptr; + HighLatencyCPSR = false; + IsSelfLoop = false; + } else if (DefCPSR) { + // This is the last CPSR defining instruction. + CPSRDef = MI; + HighLatencyCPSR = isHighLatencyCPSR(CPSRDef); + IsSelfLoop = false; + } } + MBBInfo &Info = BlockInfo[MBB.getNumber()]; + Info.HighLatencyCPSR = HighLatencyCPSR; + Info.Visited = true; return Modified; } bool Thumb2SizeReduce::runOnMachineFunction(MachineFunction &MF) { const TargetMachine &TM = MF.getTarget(); - TII = TM.getInstrInfo(); - + TII = static_cast( + TM.getSubtargetImpl()->getInstrInfo()); + STI = &TM.getSubtarget(); + + // Optimizing / minimizing size? + AttributeSet FnAttrs = MF.getFunction()->getAttributes(); + OptimizeSize = FnAttrs.hasAttribute(AttributeSet::FunctionIndex, + Attribute::OptimizeForSize); + MinimizeSize = + FnAttrs.hasAttribute(AttributeSet::FunctionIndex, Attribute::MinSize); + + BlockInfo.clear(); + BlockInfo.resize(MF.getNumBlockIDs()); + + // Visit blocks in reverse post-order so LastCPSRDef is known for all + // predecessors. + ReversePostOrderTraversal RPOT(&MF); bool Modified = false; - for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) - Modified |= ReduceMBB(*I); + for (ReversePostOrderTraversal::rpo_iterator + I = RPOT.begin(), E = RPOT.end(); I != E; ++I) + Modified |= ReduceMBB(**I); return Modified; }