From 5dde893c2bac9e1569c38429f756c1d723e8edf2 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Tue, 19 Apr 2011 18:11:49 +0000 Subject: Avoid some 's' 16-bit instruction which partially update CPSR (and add false dependency) when it isn't dependent on last CPSR defining instruction. rdar://8928208 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129773 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/ARM/Thumb2SizeReduction.cpp | 250 ++++++++++++++++++++++----------- 1 file changed, 165 insertions(+), 85 deletions(-) (limited to 'lib/Target/ARM/Thumb2SizeReduction.cpp') diff --git a/lib/Target/ARM/Thumb2SizeReduction.cpp b/lib/Target/ARM/Thumb2SizeReduction.cpp index be9c150933..74ecabf71d 100644 --- a/lib/Target/ARM/Thumb2SizeReduction.cpp +++ b/lib/Target/ARM/Thumb2SizeReduction.cpp @@ -12,6 +12,7 @@ #include "ARMAddressingModes.h" #include "ARMBaseRegisterInfo.h" #include "ARMBaseInstrInfo.h" +#include "ARMSubtarget.h" #include "Thumb2InstrInfo.h" #include "llvm/CodeGen/MachineInstr.h" #include "llvm/CodeGen/MachineInstrBuilder.h" @@ -49,82 +50,86 @@ namespace { // 1 - No cc field. // 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 }; static const ReduceEntry ReduceTable[] = { - // Wide, Narrow1, Narrow2, imm1,imm2, lo1, lo2, P/C, S - { ARM::t2ADCrr, 0, ARM::tADC, 0, 0, 0, 1, 0,0, 0 }, - { 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 }, + // Wide, Narrow1, Narrow2, imm1,imm2, lo1, lo2, P/C, PF, S + { ARM::t2ADCrr, 0, ARM::tADC, 0, 0, 0, 1, 0,0, 0,0 }, + { ARM::t2ADDri, ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 0,0, 0,0 }, + { ARM::t2ADDrr, ARM::tADDrr, ARM::tADDhirr, 0, 0, 1, 0, 0,1, 0,0 }, // Note: immediate scale is 4. - { ARM::t2ADDrSPi,ARM::tADDrSPi,0, 8, 0, 1, 0, 1,0, 1 }, - { ARM::t2ADDSri,ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 2,2, 1 }, - { ARM::t2ADDSrr,ARM::tADDrr, 0, 0, 0, 1, 0, 2,0, 1 }, - { 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::t2ADDrSPi,ARM::tADDrSPi,0, 8, 0, 1, 0, 1,0, 0,1 }, + { ARM::t2ADDSri,ARM::tADDi3, ARM::tADDi8, 3, 8, 1, 1, 2,2, 0,1 }, + { ARM::t2ADDSrr,ARM::tADDrr, 0, 0, 0, 1, 0, 2,0, 0,1 }, + { ARM::t2ANDrr, 0, ARM::tAND, 0, 0, 0, 1, 0,0, 1,0 }, + { ARM::t2ASRri, ARM::tASRri, 0, 5, 0, 1, 0, 0,0, 1,0 }, + { ARM::t2ASRrr, 0, ARM::tASRrr, 0, 0, 0, 1, 0,0, 1,0 }, + { ARM::t2BICrr, 0, ARM::tBIC, 0, 0, 0, 1, 0,0, 1,0 }, //FIXME: Disable CMN, as CCodes are backwards from compare expectations - //{ ARM::t2CMNrr, ARM::tCMN, 0, 0, 0, 1, 0, 2,0, 0 }, - { ARM::t2CMPri, ARM::tCMPi8, 0, 8, 0, 1, 0, 2,0, 0 }, - { ARM::t2CMPrr, ARM::tCMPhir, 0, 0, 0, 0, 0, 2,0, 1 }, - { ARM::t2EORrr, 0, ARM::tEOR, 0, 0, 0, 1, 0,0, 0 }, + //{ ARM::t2CMNrr, ARM::tCMN, 0, 0, 0, 1, 0, 2,0, 0,0 }, + { ARM::t2CMPri, ARM::tCMPi8, 0, 8, 0, 1, 0, 2,0, 0,0 }, + { ARM::t2CMPrr, ARM::tCMPhir, 0, 0, 0, 0, 0, 2,0, 0,1 }, + { ARM::t2EORrr, 0, ARM::tEOR, 0, 0, 0, 1, 0,0, 1,0 }, // FIXME: adr.n immediate offset must be multiple of 4. - //{ ARM::t2LEApcrelJT,ARM::tLEApcrelJT, 0, 0, 0, 1, 0, 1,0, 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 }, - { ARM::t2MOVi16,ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 1 }, + //{ ARM::t2LEApcrelJT,ARM::tLEApcrelJT, 0, 0, 0, 1, 0, 1,0, 0,0 }, + { ARM::t2LSLri, ARM::tLSLri, 0, 5, 0, 1, 0, 0,0, 1,0 }, + { ARM::t2LSLrr, 0, ARM::tLSLrr, 0, 0, 0, 1, 0,0, 1,0 }, + { ARM::t2LSRri, ARM::tLSRri, 0, 5, 0, 1, 0, 0,0, 1,0 }, + { ARM::t2LSRrr, 0, ARM::tLSRrr, 0, 0, 0, 1, 0,0, 1,0 }, + // FIXME: tMOVi8 and tMVN also partially update CPSR but they are less + // likely to cause issue in the loop. As a size / performance workaround, + // they are not marked as such. + { ARM::t2MOVi, ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 0,0 }, + { ARM::t2MOVi16,ARM::tMOVi8, 0, 8, 0, 1, 0, 0,0, 0,1 }, // FIXME: Do we need the 16-bit 'S' variant? - { ARM::t2MOVr,ARM::tMOVgpr2gpr,0, 0, 0, 0, 0, 1,0, 0 }, - { ARM::t2MOVCCr,0, ARM::tMOVCCr, 0, 0, 0, 0, 0,1, 0 }, - { ARM::t2MOVCCi,0, ARM::tMOVCCi, 0, 8, 0, 1, 0,1, 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 }, - { ARM::t2RSBri, ARM::tRSB, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2RSBSri,ARM::tRSB, 0, 0, 0, 1, 0, 2,0, 1 }, - { ARM::t2SBCrr, 0, ARM::tSBC, 0, 0, 0, 1, 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::t2SUBSri,ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 2,2, 0 }, - { ARM::t2SUBSrr,ARM::tSUBrr, 0, 0, 0, 1, 0, 2,0, 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, 2,0, 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 }, + { ARM::t2MOVr,ARM::tMOVgpr2gpr,0, 0, 0, 0, 0, 1,0, 0,0 }, + { ARM::t2MOVCCr,0, ARM::tMOVCCr, 0, 0, 0, 0, 0,1, 0,0 }, + { ARM::t2MOVCCi,0, ARM::tMOVCCi, 0, 8, 0, 1, 0,1, 0,0 }, + { ARM::t2MUL, 0, ARM::tMUL, 0, 0, 0, 1, 0,0, 1,0 }, + { ARM::t2MVNr, ARM::tMVN, 0, 0, 0, 1, 0, 0,0, 0,0 }, + { ARM::t2ORRrr, 0, ARM::tORR, 0, 0, 0, 1, 0,0, 1,0 }, + { ARM::t2REV, ARM::tREV, 0, 0, 0, 1, 0, 1,0, 0,0 }, + { ARM::t2REV16, ARM::tREV16, 0, 0, 0, 1, 0, 1,0, 0,0 }, + { ARM::t2REVSH, ARM::tREVSH, 0, 0, 0, 1, 0, 1,0, 0,0 }, + { ARM::t2RORrr, 0, ARM::tROR, 0, 0, 0, 1, 0,0, 1,0 }, + { ARM::t2RSBri, ARM::tRSB, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2RSBSri,ARM::tRSB, 0, 0, 0, 1, 0, 2,0, 0,1 }, + { ARM::t2SBCrr, 0, ARM::tSBC, 0, 0, 0, 1, 0,0, 0,0 }, + { ARM::t2SUBri, ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 0,0, 0,0 }, + { ARM::t2SUBrr, ARM::tSUBrr, 0, 0, 0, 1, 0, 0,0, 0,0 }, + { ARM::t2SUBSri,ARM::tSUBi3, ARM::tSUBi8, 3, 8, 1, 1, 2,2, 0,0 }, + { ARM::t2SUBSrr,ARM::tSUBrr, 0, 0, 0, 1, 0, 2,0, 0,0 }, + { ARM::t2SXTBr, ARM::tSXTB, 0, 0, 0, 1, 0, 1,0, 0,0 }, + { ARM::t2SXTHr, ARM::tSXTH, 0, 0, 0, 1, 0, 1,0, 0,0 }, + { ARM::t2TSTrr, ARM::tTST, 0, 0, 0, 1, 0, 2,0, 0,0 }, + { ARM::t2UXTBr, ARM::tUXTB, 0, 0, 0, 1, 0, 1,0, 0,0 }, + { ARM::t2UXTHr, ARM::tUXTH, 0, 0, 0, 1, 0, 1,0, 0,0 }, // 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, 1 }, - { ARM::t2LDRs, ARM::tLDRr, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRBi12,ARM::tLDRBi, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRBs, ARM::tLDRBr, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRHi12,ARM::tLDRHi, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2LDRHs, ARM::tLDRHr, 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::tSTRi, ARM::tSTRspi, 5, 8, 1, 0, 0,0, 1 }, - { ARM::t2STRs, ARM::tSTRr, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRBi12,ARM::tSTRBi, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRBs, ARM::tSTRBr, 0, 0, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRHi12,ARM::tSTRHi, 0, 5, 0, 1, 0, 0,0, 1 }, - { ARM::t2STRHs, ARM::tSTRHr, 0, 0, 0, 1, 0, 0,0, 1 }, - - { ARM::t2LDMIA, ARM::tLDMIA, 0, 0, 0, 1, 1, 1,1, 1 }, - { ARM::t2LDMIA_RET,0, ARM::tPOP_RET, 0, 0, 1, 1, 1,1, 1 }, - { ARM::t2LDMIA_UPD,ARM::tLDMIA_UPD,ARM::tPOP,0, 0, 1, 1, 1,1, 1 }, + { ARM::t2LDRi12,ARM::tLDRi, ARM::tLDRspi, 5, 8, 1, 0, 0,0, 0,1 }, + { ARM::t2LDRs, ARM::tLDRr, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2LDRBi12,ARM::tLDRBi, 0, 5, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2LDRBs, ARM::tLDRBr, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2LDRHi12,ARM::tLDRHi, 0, 5, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2LDRHs, ARM::tLDRHr, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2LDRSBs,ARM::tLDRSB, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2LDRSHs,ARM::tLDRSH, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2STRi12,ARM::tSTRi, ARM::tSTRspi, 5, 8, 1, 0, 0,0, 0,1 }, + { ARM::t2STRs, ARM::tSTRr, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2STRBi12,ARM::tSTRBi, 0, 5, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2STRBs, ARM::tSTRBr, 0, 0, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2STRHi12,ARM::tSTRHi, 0, 5, 0, 1, 0, 0,0, 0,1 }, + { ARM::t2STRHs, ARM::tSTRHr, 0, 0, 0, 1, 0, 0,0, 0,1 }, + + { ARM::t2LDMIA, ARM::tLDMIA, 0, 0, 0, 1, 1, 1,1, 0,1 }, + { ARM::t2LDMIA_RET,0, ARM::tPOP_RET, 0, 0, 1, 1, 1,1, 0,1 }, + { ARM::t2LDMIA_UPD,ARM::tLDMIA_UPD,ARM::tPOP,0, 0, 1, 1, 1,1, 0,1 }, // ARM::t2STM (with no basereg writeback) has no Thumb1 equivalent - { ARM::t2STMIA_UPD,ARM::tSTMIA_UPD, 0, 0, 0, 1, 1, 1,1, 1 }, - { ARM::t2STMDB_UPD, 0, ARM::tPUSH, 0, 0, 1, 1, 1,1, 1 }, + { ARM::t2STMIA_UPD,ARM::tSTMIA_UPD, 0, 0, 0, 1, 1, 1,1, 0,1 }, + { ARM::t2STMDB_UPD, 0, ARM::tPUSH, 0, 0, 1, 1, 1,1, 0,1 }, }; class Thumb2SizeReduce : public MachineFunctionPass { @@ -133,6 +138,7 @@ namespace { Thumb2SizeReduce(); const Thumb2InstrInfo *TII; + const ARMSubtarget *STI; virtual bool runOnMachineFunction(MachineFunction &MF); @@ -144,6 +150,8 @@ namespace { /// ReduceOpcodeMap - Maps wide opcode to index of entry in ReduceTable. DenseMap ReduceOpcodeMap; + bool canAddPseudoFlagDep(MachineInstr *Def, MachineInstr *Use); + bool VerifyPredAndCC(MachineInstr *MI, const ReduceEntry &Entry, bool is2Addr, ARMCC::CondCodes Pred, bool LiveCPSR, bool &HasCC, bool &CCDead); @@ -152,19 +160,20 @@ namespace { const ReduceEntry &Entry); bool ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, - const ReduceEntry &Entry, bool LiveCPSR); + const ReduceEntry &Entry, bool LiveCPSR, + MachineInstr *CPSRDef); /// ReduceTo2Addr - Reduce a 32-bit instruction to a 16-bit two-address /// instruction. bool ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry, - bool LiveCPSR); + bool LiveCPSR, MachineInstr *CPSRDef); /// 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); + bool LiveCPSR, MachineInstr *CPSRDef); /// ReduceMBB - Reduce width of instructions in the specified basic block. bool ReduceMBB(MachineBasicBlock &MBB); @@ -187,6 +196,52 @@ static bool HasImplicitCPSRDef(const TargetInstrDesc &TID) { 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 *Def, MachineInstr *Use) { + if (!Def || !STI->avoidCPSRPartialUpdate()) + return false; + + SmallSet Defs; + for (unsigned i = 0, e = Def->getNumOperands(); i != e; ++i) { + const MachineOperand &MO = Def->getOperand(i); + if (!MO.isReg() || MO.isUndef() || MO.isUse()) + continue; + unsigned Reg = MO.getReg(); + if (Reg == 0 || Reg == ARM::CPSR) + continue; + Defs.insert(Reg); + } + + for (unsigned i = 0, e = Use->getNumOperands(); i != e; ++i) { + const MachineOperand &MO = Use->getOperand(i); + if (!MO.isReg() || MO.isUndef() || MO.isDef()) + continue; + unsigned Reg = MO.getReg(); + if (Defs.count(Reg)) + 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, @@ -425,7 +480,7 @@ Thumb2SizeReduce::ReduceLoadStore(MachineBasicBlock &MBB, MachineInstr *MI, bool Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry, - bool LiveCPSR) { + bool LiveCPSR, MachineInstr *CPSRDef) { if (Entry.LowRegs1 && !VerifyLowRegs(MI)) return false; @@ -443,12 +498,12 @@ Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, switch (Opc) { default: break; case ARM::t2ADDSri: { - if (ReduceTo2Addr(MBB, MI, Entry, LiveCPSR)) + if (ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, CPSRDef)) return true; // fallthrough } case ARM::t2ADDSrr: - return ReduceToNarrow(MBB, MI, Entry, LiveCPSR); + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, CPSRDef); } } break; @@ -456,13 +511,13 @@ Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, case ARM::t2RSBri: case ARM::t2RSBSri: if (MI->getOperand(2).getImm() == 0) - return ReduceToNarrow(MBB, MI, Entry, LiveCPSR); + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, CPSRDef); 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); + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, CPSRDef); break; case ARM::t2CMPrr: { // Try to reduce to the lo-reg only version first. Why there are two @@ -471,17 +526,17 @@ Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, // 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, 1 }; - if (ReduceToNarrow(MBB, MI, NarrowEntry, LiveCPSR)) + { ARM::t2CMPrr,ARM::tCMPr, 0, 0, 0, 1, 1,2, 0, 0,1 }; + if (ReduceToNarrow(MBB, MI, NarrowEntry, LiveCPSR, CPSRDef)) return true; - return ReduceToNarrow(MBB, MI, Entry, LiveCPSR); + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, CPSRDef); } case ARM::t2ADDrSPi: { static const ReduceEntry NarrowEntry = - { ARM::t2ADDrSPi,ARM::tADDspi, 0, 7, 0, 1, 0, 1, 0, 1 }; + { ARM::t2ADDrSPi,ARM::tADDspi, 0, 7, 0, 1, 0, 1, 0, 0,1 }; if (MI->getOperand(0).getReg() == ARM::SP) - return ReduceToNarrow(MBB, MI, NarrowEntry, LiveCPSR); - return ReduceToNarrow(MBB, MI, Entry, LiveCPSR); + return ReduceToNarrow(MBB, MI, NarrowEntry, LiveCPSR, CPSRDef); + return ReduceToNarrow(MBB, MI, Entry, LiveCPSR, CPSRDef); } } return false; @@ -490,7 +545,7 @@ Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI, bool Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry, - bool LiveCPSR) { + bool LiveCPSR, MachineInstr *CPSRDef) { if (ReduceLimit2Addr != -1 && ((int)Num2Addrs >= ReduceLimit2Addr)) return false; @@ -545,6 +600,12 @@ 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 && NewTID.hasOptionalDef() && HasCC && + canAddPseudoFlagDep(CPSRDef, MI)) + return false; + // Add the 16-bit instruction. DebugLoc dl = MI->getDebugLoc(); MachineInstrBuilder MIB = BuildMI(MBB, *MI, dl, NewTID); @@ -579,7 +640,7 @@ Thumb2SizeReduce::ReduceTo2Addr(MachineBasicBlock &MBB, MachineInstr *MI, bool Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI, const ReduceEntry &Entry, - bool LiveCPSR) { + bool LiveCPSR, MachineInstr *CPSRDef) { if (ReduceLimit != -1 && ((int)NumNarrows >= ReduceLimit)) return false; @@ -632,6 +693,12 @@ 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 && NewTID.hasOptionalDef() && HasCC && + canAddPseudoFlagDep(CPSRDef, MI)) + return false; + // Add the 16-bit instruction. DebugLoc dl = MI->getDebugLoc(); MachineInstrBuilder MIB = BuildMI(MBB, *MI, dl, NewTID); @@ -679,7 +746,7 @@ Thumb2SizeReduce::ReduceToNarrow(MachineBasicBlock &MBB, MachineInstr *MI, return true; } -static bool UpdateCPSRDef(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); @@ -687,6 +754,8 @@ static bool UpdateCPSRDef(MachineInstr &MI, bool LiveCPSR) { continue; if (MO.getReg() != ARM::CPSR) continue; + + DefCPSR = true; if (!MO.isDead()) HasDef = true; } @@ -716,6 +785,7 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) { // Yes, CPSR could be livein. bool LiveCPSR = MBB.isLiveIn(ARM::CPSR); + MachineInstr *CPSRDef = 0; MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end(); MachineBasicBlock::iterator NextMII; @@ -731,7 +801,7 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) { const ReduceEntry &Entry = ReduceTable[OPI->second]; // Ignore "special" cases for now. if (Entry.Special) { - if (ReduceSpecial(MBB, MI, Entry, LiveCPSR)) { + if (ReduceSpecial(MBB, MI, Entry, LiveCPSR, CPSRDef)) { Modified = true; MachineBasicBlock::iterator I = prior(NextMII); MI = &*I; @@ -740,7 +810,8 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) { } // Try to transform to a 16-bit two-address instruction. - if (Entry.NarrowOpc2 && ReduceTo2Addr(MBB, MI, Entry, LiveCPSR)) { + if (Entry.NarrowOpc2 && + ReduceTo2Addr(MBB, MI, Entry, LiveCPSR, CPSRDef)) { Modified = true; MachineBasicBlock::iterator I = prior(NextMII); MI = &*I; @@ -748,7 +819,8 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) { } // Try to transform to a 16-bit non-two-address instruction. - if (Entry.NarrowOpc1 && ReduceToNarrow(MBB, MI, Entry, LiveCPSR)) { + if (Entry.NarrowOpc1 && + ReduceToNarrow(MBB, MI, Entry, LiveCPSR, CPSRDef)) { Modified = true; MachineBasicBlock::iterator I = prior(NextMII); MI = &*I; @@ -756,7 +828,14 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) { } ProcessNext: - LiveCPSR = UpdateCPSRDef(*MI, LiveCPSR); + bool DefCPSR = false; + LiveCPSR = UpdateCPSRDef(*MI, LiveCPSR, DefCPSR); + if (MI->getDesc().isCall()) + // Calls don't really set CPSR. + CPSRDef = 0; + else if (DefCPSR) + // This is the last CPSR defining instruction. + CPSRDef = MI; } return Modified; @@ -765,6 +844,7 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) { bool Thumb2SizeReduce::runOnMachineFunction(MachineFunction &MF) { const TargetMachine &TM = MF.getTarget(); TII = static_cast(TM.getInstrInfo()); + STI = &TM.getSubtarget(); bool Modified = false; for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) -- cgit v1.2.3