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author | Evan Cheng <evan.cheng@apple.com> | 2009-11-05 00:51:13 +0000 |
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committer | Evan Cheng <evan.cheng@apple.com> | 2009-11-05 00:51:13 +0000 |
commit | 9fb744e16945390d6ff0a631d4ad7637fec5b7b1 (patch) | |
tree | 26c2638bc572608a76206f0e0de0cebaaa2971f2 /lib/CodeGen/MachineLICM.cpp | |
parent | 8a008cc49dd1dc58332c7af9697b7798f1a07ab9 (diff) | |
download | external_llvm-9fb744e16945390d6ff0a631d4ad7637fec5b7b1.zip external_llvm-9fb744e16945390d6ff0a631d4ad7637fec5b7b1.tar.gz external_llvm-9fb744e16945390d6ff0a631d4ad7637fec5b7b1.tar.bz2 |
Code refactoring.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86085 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/MachineLICM.cpp')
-rw-r--r-- | lib/CodeGen/MachineLICM.cpp | 107 |
1 files changed, 58 insertions, 49 deletions
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp index 1306aa6..de3ab27 100644 --- a/lib/CodeGen/MachineLICM.cpp +++ b/lib/CodeGen/MachineLICM.cpp @@ -111,6 +111,13 @@ namespace { /// be hoistable. MachineInstr *ExtractHoistableLoad(MachineInstr *MI); + /// EliminateCSE - Given a LICM'ed instruction, look for an instruction on + /// the preheader that compute the same value. If it's found, do a RAU on + /// with the definition of the existing instruction rather than hoisting + /// the instruction to the preheader. + bool EliminateCSE(MachineInstr *MI, + DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator &CI); + /// Hoist - When an instruction is found to only use loop invariant operands /// that is safe to hoist, this instruction is called to do the dirty work. /// @@ -349,37 +356,6 @@ bool MachineLICM::IsProfitableToHoist(MachineInstr &MI) { return true; } -static const MachineInstr *LookForDuplicate(const MachineInstr *MI, - std::vector<const MachineInstr*> &PrevMIs, - MachineRegisterInfo *RegInfo) { - unsigned NumOps = MI->getNumOperands(); - for (unsigned i = 0, e = PrevMIs.size(); i != e; ++i) { - const MachineInstr *PrevMI = PrevMIs[i]; - unsigned NumOps2 = PrevMI->getNumOperands(); - if (NumOps != NumOps2) - continue; - bool IsSame = true; - for (unsigned j = 0; j != NumOps; ++j) { - const MachineOperand &MO = MI->getOperand(j); - if (MO.isReg() && MO.isDef()) { - if (RegInfo->getRegClass(MO.getReg()) != - RegInfo->getRegClass(PrevMI->getOperand(j).getReg())) { - IsSame = false; - break; - } - continue; - } - if (!MO.isIdenticalTo(PrevMI->getOperand(j))) { - IsSame = false; - break; - } - } - if (IsSame) - return PrevMI; - } - return 0; -} - MachineInstr *MachineLICM::ExtractHoistableLoad(MachineInstr *MI) { // If not, we may be able to unfold a load and hoist that. // First test whether the instruction is loading from an amenable @@ -456,6 +432,55 @@ void MachineLICM::InitCSEMap(MachineBasicBlock *BB) { } } +static const MachineInstr *LookForDuplicate(const MachineInstr *MI, + std::vector<const MachineInstr*> &PrevMIs, + MachineRegisterInfo *RegInfo) { + unsigned NumOps = MI->getNumOperands(); + for (unsigned i = 0, e = PrevMIs.size(); i != e; ++i) { + const MachineInstr *PrevMI = PrevMIs[i]; + unsigned NumOps2 = PrevMI->getNumOperands(); + if (NumOps != NumOps2) + continue; + bool IsSame = true; + for (unsigned j = 0; j != NumOps; ++j) { + const MachineOperand &MO = MI->getOperand(j); + if (MO.isReg() && MO.isDef()) { + if (RegInfo->getRegClass(MO.getReg()) != + RegInfo->getRegClass(PrevMI->getOperand(j).getReg())) { + IsSame = false; + break; + } + continue; + } + if (!MO.isIdenticalTo(PrevMI->getOperand(j))) { + IsSame = false; + break; + } + } + if (IsSame) + return PrevMI; + } + return 0; +} + +bool MachineLICM::EliminateCSE(MachineInstr *MI, + DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator &CI) { + if (CI != CSEMap.end()) { + if (const MachineInstr *Dup = LookForDuplicate(MI, CI->second, RegInfo)) { + DEBUG(errs() << "CSEing " << *MI << " with " << *Dup); + for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + const MachineOperand &MO = MI->getOperand(i); + if (MO.isReg() && MO.isDef()) + RegInfo->replaceRegWith(MO.getReg(), Dup->getOperand(i).getReg()); + } + MI->eraseFromParent(); + ++NumCSEed; + return true; + } + } + return false; +} + /// Hoist - When an instruction is found to use only loop invariant operands /// that are safe to hoist, this instruction is called to do the dirty work. /// @@ -488,24 +513,8 @@ void MachineLICM::Hoist(MachineInstr *MI) { unsigned Opcode = MI->getOpcode(); DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator CI = CSEMap.find(Opcode); - bool DoneCSE = false; - if (CI != CSEMap.end()) { - const MachineInstr *Dup = LookForDuplicate(MI, CI->second, RegInfo); - if (Dup) { - DEBUG(errs() << "CSEing " << *MI << " with " << *Dup); - for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { - const MachineOperand &MO = MI->getOperand(i); - if (MO.isReg() && MO.isDef()) - RegInfo->replaceRegWith(MO.getReg(), Dup->getOperand(i).getReg()); - } - MI->eraseFromParent(); - DoneCSE = true; - ++NumCSEed; - } - } - - // Otherwise, splice the instruction to the preheader. - if (!DoneCSE) { + if (!EliminateCSE(MI, CI)) { + // Otherwise, splice the instruction to the preheader. CurPreheader->splice(CurPreheader->getFirstTerminator(),MI->getParent(),MI); // Add to the CSE map. |