It's important for the cmp-and-swap to balance

loads and stores but it's even more important for
it to store the right value.:(



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55319 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2008-08-25 18:53:26 +00:00
parent cb3c51a4ae
commit 65e3973dff

View File

@ -4040,38 +4040,56 @@ PPCTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
unsigned oldval = MI->getOperand(3).getReg();
unsigned newval = MI->getOperand(4).getReg();
MachineBasicBlock *loopMBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *loop1MBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *loop2MBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *midMBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *exitMBB = F->CreateMachineBasicBlock(LLVM_BB);
F->insert(It, loopMBB);
F->insert(It, loop1MBB);
F->insert(It, loop2MBB);
F->insert(It, midMBB);
F->insert(It, exitMBB);
exitMBB->transferSuccessors(BB);
// thisMBB:
// ...
// fallthrough --> loopMBB
BB->addSuccessor(loopMBB);
BB->addSuccessor(loop1MBB);
// loopMBB:
// loop1MBB:
// l[wd]arx dest, ptr
// cmp[wd] CR1, dest, oldval
// cmp[wd] dest, oldval
// bne- midMBB
// loop2MBB:
// st[wd]cx. newval, ptr
// bne- CR1, exitMBB
// bne- loopMBB
// fallthrough --> exitMBB
BB = loopMBB;
// b exitBB
// midMBB:
// st[wd]cx. dest, ptr
// exitBB:
BB = loop1MBB;
BuildMI(BB, TII->get(is64bit ? PPC::LDARX : PPC::LWARX), dest)
.addReg(ptrA).addReg(ptrB);
BuildMI(BB, TII->get(is64bit ? PPC::CMPD : PPC::CMPW), PPC::CR1)
BuildMI(BB, TII->get(is64bit ? PPC::CMPD : PPC::CMPW), PPC::CR0)
.addReg(oldval).addReg(dest);
BuildMI(BB, TII->get(PPC::BCC))
.addImm(PPC::PRED_NE).addReg(PPC::CR0).addMBB(midMBB);
BB->addSuccessor(loop2MBB);
BB->addSuccessor(midMBB);
BB = loop2MBB;
BuildMI(BB, TII->get(is64bit ? PPC::STDCX : PPC::STWCX))
.addReg(newval).addReg(ptrA).addReg(ptrB);
BuildMI(BB, TII->get(PPC::BCC))
.addImm(PPC::PRED_NE).addReg(PPC::CR1).addMBB(exitMBB);
BuildMI(BB, TII->get(PPC::BCC))
.addImm(PPC::PRED_NE).addReg(PPC::CR0).addMBB(loopMBB);
BB->addSuccessor(loopMBB);
.addImm(PPC::PRED_NE).addReg(PPC::CR0).addMBB(loop1MBB);
BuildMI(BB, TII->get(PPC::B)).addMBB(exitMBB);
BB->addSuccessor(loop1MBB);
BB->addSuccessor(exitMBB);
BB = midMBB;
BuildMI(BB, TII->get(is64bit ? PPC::STDCX : PPC::STWCX))
.addReg(dest).addReg(ptrA).addReg(ptrB);
BB->addSuccessor(exitMBB);
// exitMBB:
// ...
BB = exitMBB;