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author | Bill Wendling <isanbard@gmail.com> | 2010-06-25 20:48:10 +0000 |
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committer | Bill Wendling <isanbard@gmail.com> | 2010-06-25 20:48:10 +0000 |
commit | 730c07e50d03be3d64fd4d808c590e6890d32178 (patch) | |
tree | 2d77b286394d642ad1c16c4c9cac0a9ef7bffabd /lib/CodeGen | |
parent | 39d258aa49717218628c158504996482bbbb0a5a (diff) | |
download | external_llvm-730c07e50d03be3d64fd4d808c590e6890d32178.zip external_llvm-730c07e50d03be3d64fd4d808c590e6890d32178.tar.gz external_llvm-730c07e50d03be3d64fd4d808c590e6890d32178.tar.bz2 |
- Reapply r106066 now that the bzip2 build regression has been fixed.
- 2010-06-25-CoalescerSubRegDefDead.ll is the testcase for r106878.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106880 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen')
-rw-r--r-- | lib/CodeGen/MachineSink.cpp | 60 |
1 files changed, 10 insertions, 50 deletions
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp index 4a9ea72..61334fc 100644 --- a/lib/CodeGen/MachineSink.cpp +++ b/lib/CodeGen/MachineSink.cpp @@ -25,7 +25,6 @@ #include "llvm/Target/TargetRegisterInfo.h" #include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" -#include "llvm/ADT/SmallSet.h" #include "llvm/ADT/Statistic.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" @@ -62,7 +61,6 @@ namespace { bool ProcessBlock(MachineBasicBlock &MBB); bool SinkInstruction(MachineInstr *MI, bool &SawStore); bool AllUsesDominatedByBlock(unsigned Reg, MachineBasicBlock *MBB) const; - bool LiveOutOfBasicBlock(const MachineInstr *MI, unsigned Reg) const; }; } // end anonymous namespace @@ -168,44 +166,6 @@ bool MachineSinking::ProcessBlock(MachineBasicBlock &MBB) { return MadeChange; } -/// LiveOutOfBasicBlock - Determine if the physical register, defined and dead -/// in MI, is live on exit from the basic block. -bool MachineSinking::LiveOutOfBasicBlock(const MachineInstr *MI, - unsigned Reg) const { - assert(TargetRegisterInfo::isPhysicalRegister(Reg) && - "Only want to determine if a physical register is live out of a BB!"); - - const MachineBasicBlock *MBB = MI->getParent(); - SmallSet<unsigned, 8> KilledRegs; - MachineBasicBlock::const_iterator I = MBB->end(); - MachineBasicBlock::const_iterator E = MBB->begin(); - assert(I != E && "How can there be an empty block at this point?!"); - - // Loop through the instructions bottom-up. If we see a kill of the preg - // first, then it's not live out of the BB. If we see a use or def first, then - // we assume that it is live out of the BB. - do { - const MachineInstr &CurMI = *--I; - - for (unsigned i = 0, e = CurMI.getNumOperands(); i != e; ++i) { - const MachineOperand &MO = CurMI.getOperand(i); - if (!MO.isReg()) continue; // Ignore non-register operands. - - unsigned MOReg = MO.getReg(); - if (MOReg == 0) continue; - - if (MOReg == Reg) { - if (MO.isKill()) - return false; - if (MO.isUse() || MO.isDef()) - return true; - } - } - } while (I != E); - - return false; -} - /// SinkInstruction - Determine whether it is safe to sink the specified machine /// instruction out of its current block into a successor. bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) { @@ -228,7 +188,6 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) { // SuccToSinkTo - This is the successor to sink this instruction to, once we // decide. MachineBasicBlock *SuccToSinkTo = 0; - SmallVector<unsigned, 4> PhysRegs; for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { const MachineOperand &MO = MI->getOperand(i); @@ -257,12 +216,9 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) { if (AllocatableSet.test(AliasReg)) return false; } - } else { - if (!MO.isDead()) - // A def that isn't dead. We can't move it. - return false; - else - PhysRegs.push_back(Reg); + } else if (!MO.isDead()) { + // A def that isn't dead. We can't move it. + return false; } } else { // Virtual register uses are always safe to sink. @@ -329,10 +285,14 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) { // If the instruction to move defines a dead physical register which is live // when leaving the basic block, don't move it because it could turn into a // "zombie" define of that preg. E.g., EFLAGS. (<rdar://problem/8030636>) - for (SmallVectorImpl<unsigned>::const_iterator - I = PhysRegs.begin(), E = PhysRegs.end(); I != E; ++I) - if (LiveOutOfBasicBlock(MI, *I)) + for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) { + const MachineOperand &MO = MI->getOperand(I); + if (!MO.isReg()) continue; + unsigned Reg = MO.getReg(); + if (Reg == 0 || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue; + if (SuccToSinkTo->isLiveIn(Reg)) return false; + } DEBUG(dbgs() << "Sink instr " << *MI << "\tinto block " << *SuccToSinkTo); |