X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FTarget%2FPowerPC%2FPPCInstrInfo.cpp;h=a0370a0f069362a67ae549cd97a2837ca44c96a6;hp=b844f63c86f7609d4a4a7199e1c97e803160322b;hb=dad591a4355b39b64190c57ce266e0e2dbf1656a;hpb=27670548239fe53bf364766fe5754f2b33bd518e diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp index b844f63c86f..a0370a0f069 100644 --- a/lib/Target/PowerPC/PPCInstrInfo.cpp +++ b/lib/Target/PowerPC/PPCInstrInfo.cpp @@ -52,9 +52,6 @@ opt DisableCTRLoopAnal("disable-ppc-ctrloop-analysis", cl::Hidden, static cl::opt DisableCmpOpt("disable-ppc-cmp-opt", cl::desc("Disable compare instruction optimization"), cl::Hidden); -static cl::opt DisableVSXFMAMutate("disable-ppc-vsx-fma-mutation", -cl::desc("Disable VSX FMA instruction mutation"), cl::Hidden); - static cl::opt VSXSelfCopyCrash("crash-on-ppc-vsx-self-copy", cl::desc("Causes the backend to crash instead of generating a nop VSX copy"), cl::Hidden); @@ -1608,294 +1605,6 @@ unsigned PPCInstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const { } } -#undef DEBUG_TYPE -#define DEBUG_TYPE "ppc-vsx-fma-mutate" - -namespace { - // PPCVSXFMAMutate pass - For copies between VSX registers and non-VSX registers - // (Altivec and scalar floating-point registers), we need to transform the - // copies into subregister copies with other restrictions. - struct PPCVSXFMAMutate : public MachineFunctionPass { - static char ID; - PPCVSXFMAMutate() : MachineFunctionPass(ID) { - initializePPCVSXFMAMutatePass(*PassRegistry::getPassRegistry()); - } - - LiveIntervals *LIS; - const PPCInstrInfo *TII; - -protected: - bool processBlock(MachineBasicBlock &MBB) { - bool Changed = false; - - MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo(); - const TargetRegisterInfo *TRI = &TII->getRegisterInfo(); - for (MachineBasicBlock::iterator I = MBB.begin(), IE = MBB.end(); - I != IE; ++I) { - MachineInstr *MI = I; - - // The default (A-type) VSX FMA form kills the addend (it is taken from - // the target register, which is then updated to reflect the result of - // the FMA). If the instruction, however, kills one of the registers - // used for the product, then we can use the M-form instruction (which - // will take that value from the to-be-defined register). - - int AltOpc = PPC::getAltVSXFMAOpcode(MI->getOpcode()); - if (AltOpc == -1) - continue; - - // This pass is run after register coalescing, and so we're looking for - // a situation like this: - // ... - // %vreg5 = COPY %vreg9; VSLRC:%vreg5,%vreg9 - // %vreg5 = XSMADDADP %vreg5, %vreg17, %vreg16, - // %RM; VSLRC:%vreg5,%vreg17,%vreg16 - // ... - // %vreg9 = XSMADDADP %vreg9, %vreg17, %vreg19, - // %RM; VSLRC:%vreg9,%vreg17,%vreg19 - // ... - // Where we can eliminate the copy by changing from the A-type to the - // M-type instruction. Specifically, for this example, this means: - // %vreg5 = XSMADDADP %vreg5, %vreg17, %vreg16, - // %RM; VSLRC:%vreg5,%vreg17,%vreg16 - // is replaced by: - // %vreg16 = XSMADDMDP %vreg16, %vreg18, %vreg9, - // %RM; VSLRC:%vreg16,%vreg18,%vreg9 - // and we remove: %vreg5 = COPY %vreg9; VSLRC:%vreg5,%vreg9 - - SlotIndex FMAIdx = LIS->getInstructionIndex(MI); - - VNInfo *AddendValNo = - LIS->getInterval(MI->getOperand(1).getReg()).Query(FMAIdx).valueIn(); - MachineInstr *AddendMI = LIS->getInstructionFromIndex(AddendValNo->def); - - // The addend and this instruction must be in the same block. - - if (!AddendMI || AddendMI->getParent() != MI->getParent()) - continue; - - // The addend must be a full copy within the same register class. - - if (!AddendMI->isFullCopy()) - continue; - - unsigned AddendSrcReg = AddendMI->getOperand(1).getReg(); - if (TargetRegisterInfo::isVirtualRegister(AddendSrcReg)) { - if (MRI.getRegClass(AddendMI->getOperand(0).getReg()) != - MRI.getRegClass(AddendSrcReg)) - continue; - } else { - // If AddendSrcReg is a physical register, make sure the destination - // register class contains it. - if (!MRI.getRegClass(AddendMI->getOperand(0).getReg()) - ->contains(AddendSrcReg)) - continue; - } - - // In theory, there could be other uses of the addend copy before this - // fma. We could deal with this, but that would require additional - // logic below and I suspect it will not occur in any relevant - // situations. Additionally, check whether the copy source is killed - // prior to the fma. In order to replace the addend here with the - // source of the copy, it must still be live here. We can't use - // interval testing for a physical register, so as long as we're - // walking the MIs we may as well test liveness here. - bool OtherUsers = false, KillsAddendSrc = false; - for (auto J = std::prev(I), JE = MachineBasicBlock::iterator(AddendMI); - J != JE; --J) { - if (J->readsVirtualRegister(AddendMI->getOperand(0).getReg())) { - OtherUsers = true; - break; - } - if (J->modifiesRegister(AddendSrcReg, TRI) || - J->killsRegister(AddendSrcReg, TRI)) { - KillsAddendSrc = true; - break; - } - } - - if (OtherUsers || KillsAddendSrc) - continue; - - // Find one of the product operands that is killed by this instruction. - - unsigned KilledProdOp = 0, OtherProdOp = 0; - if (LIS->getInterval(MI->getOperand(2).getReg()) - .Query(FMAIdx).isKill()) { - KilledProdOp = 2; - OtherProdOp = 3; - } else if (LIS->getInterval(MI->getOperand(3).getReg()) - .Query(FMAIdx).isKill()) { - KilledProdOp = 3; - OtherProdOp = 2; - } - - // If there are no killed product operands, then this transformation is - // likely not profitable. - if (!KilledProdOp) - continue; - - // For virtual registers, verify that the addend source register - // is live here (as should have been assured above). - assert((!TargetRegisterInfo::isVirtualRegister(AddendSrcReg) || - LIS->getInterval(AddendSrcReg).liveAt(FMAIdx)) && - "Addend source register is not live!"); - - // Transform: (O2 * O3) + O1 -> (O2 * O1) + O3. - - unsigned AddReg = AddendMI->getOperand(1).getReg(); - unsigned KilledProdReg = MI->getOperand(KilledProdOp).getReg(); - unsigned OtherProdReg = MI->getOperand(OtherProdOp).getReg(); - - unsigned AddSubReg = AddendMI->getOperand(1).getSubReg(); - unsigned KilledProdSubReg = MI->getOperand(KilledProdOp).getSubReg(); - unsigned OtherProdSubReg = MI->getOperand(OtherProdOp).getSubReg(); - - bool AddRegKill = AddendMI->getOperand(1).isKill(); - bool KilledProdRegKill = MI->getOperand(KilledProdOp).isKill(); - bool OtherProdRegKill = MI->getOperand(OtherProdOp).isKill(); - - bool AddRegUndef = AddendMI->getOperand(1).isUndef(); - bool KilledProdRegUndef = MI->getOperand(KilledProdOp).isUndef(); - bool OtherProdRegUndef = MI->getOperand(OtherProdOp).isUndef(); - - unsigned OldFMAReg = MI->getOperand(0).getReg(); - - // The transformation doesn't work well with things like: - // %vreg5 = A-form-op %vreg5, %vreg11, %vreg5; - // so leave such things alone. - if (OldFMAReg == KilledProdReg) - continue; - - assert(OldFMAReg == AddendMI->getOperand(0).getReg() && - "Addend copy not tied to old FMA output!"); - - DEBUG(dbgs() << "VSX FMA Mutation:\n " << *MI;); - - MI->getOperand(0).setReg(KilledProdReg); - MI->getOperand(1).setReg(KilledProdReg); - MI->getOperand(3).setReg(AddReg); - MI->getOperand(2).setReg(OtherProdReg); - - MI->getOperand(0).setSubReg(KilledProdSubReg); - MI->getOperand(1).setSubReg(KilledProdSubReg); - MI->getOperand(3).setSubReg(AddSubReg); - MI->getOperand(2).setSubReg(OtherProdSubReg); - - MI->getOperand(1).setIsKill(KilledProdRegKill); - MI->getOperand(3).setIsKill(AddRegKill); - MI->getOperand(2).setIsKill(OtherProdRegKill); - - MI->getOperand(1).setIsUndef(KilledProdRegUndef); - MI->getOperand(3).setIsUndef(AddRegUndef); - MI->getOperand(2).setIsUndef(OtherProdRegUndef); - - MI->setDesc(TII->get(AltOpc)); - - DEBUG(dbgs() << " -> " << *MI); - - // The killed product operand was killed here, so we can reuse it now - // for the result of the fma. - - LiveInterval &FMAInt = LIS->getInterval(OldFMAReg); - VNInfo *FMAValNo = FMAInt.getVNInfoAt(FMAIdx.getRegSlot()); - for (auto UI = MRI.reg_nodbg_begin(OldFMAReg), UE = MRI.reg_nodbg_end(); - UI != UE;) { - MachineOperand &UseMO = *UI; - MachineInstr *UseMI = UseMO.getParent(); - ++UI; - - // Don't replace the result register of the copy we're about to erase. - if (UseMI == AddendMI) - continue; - - UseMO.setReg(KilledProdReg); - UseMO.setSubReg(KilledProdSubReg); - } - - // Extend the live intervals of the killed product operand to hold the - // fma result. - - LiveInterval &NewFMAInt = LIS->getInterval(KilledProdReg); - for (LiveInterval::iterator AI = FMAInt.begin(), AE = FMAInt.end(); - AI != AE; ++AI) { - // Don't add the segment that corresponds to the original copy. - if (AI->valno == AddendValNo) - continue; - - VNInfo *NewFMAValNo = - NewFMAInt.getNextValue(AI->start, - LIS->getVNInfoAllocator()); - - NewFMAInt.addSegment(LiveInterval::Segment(AI->start, AI->end, - NewFMAValNo)); - } - DEBUG(dbgs() << " extended: " << NewFMAInt << '\n'); - - FMAInt.removeValNo(FMAValNo); - DEBUG(dbgs() << " trimmed: " << FMAInt << '\n'); - - // Remove the (now unused) copy. - - DEBUG(dbgs() << " removing: " << *AddendMI << '\n'); - LIS->RemoveMachineInstrFromMaps(AddendMI); - AddendMI->eraseFromParent(); - - Changed = true; - } - - return Changed; - } - -public: - bool runOnMachineFunction(MachineFunction &MF) override { - // If we don't have VSX then go ahead and return without doing - // anything. - const PPCSubtarget &STI = MF.getSubtarget(); - if (!STI.hasVSX()) - return false; - - LIS = &getAnalysis(); - - TII = STI.getInstrInfo(); - - bool Changed = false; - - if (DisableVSXFMAMutate) - return Changed; - - for (MachineFunction::iterator I = MF.begin(); I != MF.end();) { - MachineBasicBlock &B = *I++; - if (processBlock(B)) - Changed = true; - } - - return Changed; - } - - void getAnalysisUsage(AnalysisUsage &AU) const override { - AU.addRequired(); - AU.addPreserved(); - AU.addRequired(); - AU.addPreserved(); - MachineFunctionPass::getAnalysisUsage(AU); - } - }; -} - -INITIALIZE_PASS_BEGIN(PPCVSXFMAMutate, DEBUG_TYPE, - "PowerPC VSX FMA Mutation", false, false) -INITIALIZE_PASS_DEPENDENCY(LiveIntervals) -INITIALIZE_PASS_DEPENDENCY(SlotIndexes) -INITIALIZE_PASS_END(PPCVSXFMAMutate, DEBUG_TYPE, - "PowerPC VSX FMA Mutation", false, false) - -char &llvm::PPCVSXFMAMutateID = PPCVSXFMAMutate::ID; - -char PPCVSXFMAMutate::ID = 0; -FunctionPass* -llvm::createPPCVSXFMAMutatePass() { return new PPCVSXFMAMutate(); } - #undef DEBUG_TYPE #define DEBUG_TYPE "ppc-vsx-copy"