diff options
| -rw-r--r-- | lib/CodeGen/TwoAddressInstructionPass.cpp | 87 | ||||
| -rw-r--r-- | test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll | 23 |
2 files changed, 102 insertions, 8 deletions
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp index 42d517b2e5..4724c3a127 100644 --- a/lib/CodeGen/TwoAddressInstructionPass.cpp +++ b/lib/CodeGen/TwoAddressInstructionPass.cpp @@ -88,6 +88,9 @@ namespace { bool NoUseAfterLastDef(unsigned Reg, MachineBasicBlock *MBB, unsigned Dist, unsigned &LastDef); + MachineInstr *FindLastUseInMBB(unsigned Reg, MachineBasicBlock *MBB, + unsigned Dist); + bool isProfitableToCommute(unsigned regB, unsigned regC, MachineInstr *MI, MachineBasicBlock *MBB, unsigned Dist); @@ -310,6 +313,28 @@ bool TwoAddressInstructionPass::NoUseAfterLastDef(unsigned Reg, return !(LastUse > LastDef && LastUse < Dist); } +MachineInstr *TwoAddressInstructionPass::FindLastUseInMBB(unsigned Reg, + MachineBasicBlock *MBB, + unsigned Dist) { + unsigned LastUseDist = Dist; + MachineInstr *LastUse = 0; + for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(Reg), + E = MRI->reg_end(); I != E; ++I) { + MachineOperand &MO = I.getOperand(); + MachineInstr *MI = MO.getParent(); + if (MI->getParent() != MBB) + continue; + DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(MI); + if (DI == DistanceMap.end()) + continue; + if (MO.isUse() && DI->second < LastUseDist) { + LastUse = DI->first; + LastUseDist = DI->second; + } + } + return LastUse; +} + /// isCopyToReg - Return true if the specified MI is a copy instruction or /// a extract_subreg instruction. It also returns the source and destination /// registers and whether they are physical registers by reference. @@ -684,7 +709,9 @@ void TwoAddressInstructionPass::ProcessCopy(MachineInstr *MI, /// isSafeToDelete - If the specified instruction does not produce any side /// effects and all of its defs are dead, then it's safe to delete. -static bool isSafeToDelete(MachineInstr *MI, const TargetInstrInfo *TII) { +static bool isSafeToDelete(MachineInstr *MI, unsigned Reg, + const TargetInstrInfo *TII, + SmallVector<unsigned, 4> &Kills) { const TargetInstrDesc &TID = MI->getDesc(); if (TID.mayStore() || TID.isCall()) return false; @@ -693,10 +720,12 @@ static bool isSafeToDelete(MachineInstr *MI, const TargetInstrInfo *TII) { for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { MachineOperand &MO = MI->getOperand(i); - if (!MO.isReg() || !MO.isDef()) + if (!MO.isReg()) continue; - if (!MO.isDead()) + if (MO.isDef() && !MO.isDead()) return false; + if (MO.isUse() && MO.getReg() != Reg && MO.isKill()) + Kills.push_back(MO.getReg()); } return true; @@ -787,11 +816,53 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) { if (!isKilled(*mi, regB, MRI, TII)) { // If regA is dead and the instruction can be deleted, just delete // it so it doesn't clobber regB. - if (mi->getOperand(ti).isDead() && isSafeToDelete(mi, TII)) { - mbbi->erase(mi); // Nuke the old inst. - mi = nmi; - ++NumDeletes; - break; // Done with this instruction. + SmallVector<unsigned, 4> Kills; + if (mi->getOperand(ti).isDead() && + isSafeToDelete(mi, regB, TII, Kills)) { + SmallVector<std::pair<std::pair<unsigned, bool> + ,MachineInstr*>, 4> NewKills; + bool ReallySafe = true; + // If this instruction kills some virtual registers, we need + // update the kill information. If it's not possible to do so, + // then bail out. + while (!Kills.empty()) { + unsigned Kill = Kills.back(); + Kills.pop_back(); + if (TargetRegisterInfo::isPhysicalRegister(Kill)) { + ReallySafe = false; + break; + } + MachineInstr *LastKill = FindLastUseInMBB(Kill, &*mbbi, Dist); + if (LastKill) { + bool isModRef = LastKill->modifiesRegister(Kill); + NewKills.push_back(std::make_pair(std::make_pair(Kill,isModRef), + LastKill)); + } else { + ReallySafe = false; + break; + } + } + + if (ReallySafe) { + if (LV) { + while (!NewKills.empty()) { + MachineInstr *NewKill = NewKills.back().second; + unsigned Kill = NewKills.back().first.first; + bool isDead = NewKills.back().first.second; + NewKills.pop_back(); + if (LV->removeVirtualRegisterKilled(Kill, mi)) { + if (isDead) + LV->addVirtualRegisterDead(Kill, NewKill); + else + LV->addVirtualRegisterKilled(Kill, NewKill); + } + } + } + mbbi->erase(mi); // Nuke the old inst. + mi = nmi; + ++NumDeletes; + break; // Done with this instruction. + } } // If this instruction is commutative, check to see if C dies. If diff --git a/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll b/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll new file mode 100644 index 0000000000..70cb4ff3c8 --- /dev/null +++ b/test/CodeGen/X86/2009-04-27-LiveIntervalsAssert2.ll @@ -0,0 +1,23 @@ +; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin9 +; PR4051 + +define void @int163(i32 %p_4, i32 %p_5) nounwind { +entry: + %0 = tail call i32 @foo(i32 1) nounwind ; <i32> [#uses=2] + %1 = icmp eq i32 %0, 0 ; <i1> [#uses=1] + br i1 %1, label %bb.i, label %bar.exit + +bb.i: ; preds = %entry + %2 = lshr i32 1, %0 ; <i32> [#uses=1] + %3 = icmp eq i32 %2, 0 ; <i1> [#uses=1] + %retval.i = select i1 %3, i32 1, i32 %p_5 ; <i32> [#uses=1] + br label %bar.exit + +bar.exit: ; preds = %bb.i, %entry + %4 = phi i32 [ %retval.i, %bb.i ], [ %p_5, %entry ] ; <i32> [#uses=1] + %5 = icmp eq i32 %4, 0 ; <i1> [#uses=0] + %6 = tail call i32 @foo(i32 %p_5) nounwind ; <i32> [#uses=0] + ret void +} + +declare i32 @foo(i32) |