Get rid of RegScavenger::backwards() before the bitrot spreads.

If we need it one day, there is nothing wrong with putting it back in.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78337 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 64 deletions

diff --git a/lib/CodeGen/RegisterScavenging.cpp b/lib/CodeGen/RegisterScavenging.cpp
index c3e03ab676..79ea579492 100644
--- a/lib/CodeGen/RegisterScavenging.cpp
+++ b/lib/CodeGen/RegisterScavenging.cpp
@@ -294,70 +294,6 @@ void RegScavenger::forward() {
   }
 }
 
-void RegScavenger::backward() {
-  assert(Tracking && "Not tracking states!");
-  assert(MBBI != MBB->begin() && "Already at start of basic block!");
-  // Move ptr backward.
-  MBBI = prior(MBBI);
-
-  MachineInstr *MI = MBBI;
-  DistanceMap.erase(MI);
-  --CurrDist;
-
-  // Separate register operands into 3 classes: uses, defs, earlyclobbers.
-  SmallVector<std::pair<const MachineOperand*,unsigned>, 4> UseMOs;
-  SmallVector<std::pair<const MachineOperand*,unsigned>, 4> DefMOs;
-  SmallVector<std::pair<const MachineOperand*,unsigned>, 4> EarlyClobberMOs;
-  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
-    const MachineOperand &MO = MI->getOperand(i);
-    if (!MO.isReg() || MO.getReg() == 0 || MO.isUndef())
-      continue;
-    if (MO.isUse())
-      UseMOs.push_back(std::make_pair(&MO,i));
-    else if (MO.isEarlyClobber())
-      EarlyClobberMOs.push_back(std::make_pair(&MO,i));
-    else
-      DefMOs.push_back(std::make_pair(&MO,i));
-  }
-
-
-  // Process defs first.
-  unsigned NumECs = EarlyClobberMOs.size();
-  unsigned NumDefs = DefMOs.size();
-  for (unsigned i = 0, e = NumECs + NumDefs; i != e; ++i) {
-    const MachineOperand &MO = (i < NumDefs)
-      ? *DefMOs[i].first : *EarlyClobberMOs[i-NumDefs].first;
-    unsigned Idx = (i < NumECs)
-      ? DefMOs[i].second : EarlyClobberMOs[i-NumDefs].second;
-    if (MO.isUndef())
-      continue;
-
-    // Skip two-address destination operand.
-    if (MI->isRegTiedToUseOperand(Idx))
-      continue;
-
-    unsigned Reg = MO.getReg();
-    assert(isUsed(Reg));
-    if (!isReserved(Reg))
-      setUnused(Reg, MI);
-  }
-
-  // Process uses.
-  BitVector UseRegs(NumPhysRegs);
-  for (unsigned i = 0, e = UseMOs.size(); i != e; ++i) {
-    const MachineOperand MO = *UseMOs[i].first;
-    unsigned Reg = MO.getReg();
-    assert(isUnused(Reg) || isReserved(Reg));
-    UseRegs.set(Reg);
-
-    // Set the sub-registers as "used".
-    for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
-         unsigned SubReg = *SubRegs; ++SubRegs)
-      UseRegs.set(SubReg);
-  }
-  setUsed(UseRegs);
-}
-
 void RegScavenger::getRegsUsed(BitVector &used, bool includeReserved) {
   if (includeReserved)
     used = ~RegsAvailable;