Commit 904dbdb2 authored by Tanya Lattner's avatar Tanya Lattner
Browse files

Merge 64124 frm mainline. 

Turns out AnalyzeBranch can modify the mbb being analyzed. This is a nasty
suprise to some callers, e.g. register coalescer. For now, add an parameter
that tells AnalyzeBranch whether it's safe to modify the mbb. A better
solution is out there, but I don't have time to deal with it right now.

llvm-svn: 64518
parent 7792a835

llvm/include/llvm/Target/TargetInstrInfo.h

+5 −1
Original line number Diff line number Diff line
@@ -195,9 +195,13 @@ public: 
  /// Note that RemoveBranch and InsertBranch must be implemented to support

  /// cases where this method returns success.

  ///

  /// If AllowModify is true, then this routine is allowed to modify the basic

  /// block (e.g. delete instructions after the unconditional branch).

  ///

  virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,

                             MachineBasicBlock *&FBB,

                             SmallVectorImpl<MachineOperand> &Cond) const {

                             SmallVectorImpl<MachineOperand> &Cond,

                             bool AllowModify = false) const {

    return true;

  }

llvm/lib/CodeGen/BranchFolding.cpp

+6 −6
Original line number Diff line number Diff line
@@ -191,7 +191,7 @@ bool BranchFolder::runOnMachineFunction(MachineFunction &MF) { 
  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; I++) {

    MachineBasicBlock *MBB = I, *TBB = 0, *FBB = 0;

    SmallVector<MachineOperand, 4> Cond;

    if (!TII->AnalyzeBranch(*MBB, TBB, FBB, Cond))

    if (!TII->AnalyzeBranch(*MBB, TBB, FBB, Cond, true))

      EverMadeChange |= MBB->CorrectExtraCFGEdges(TBB, FBB, !Cond.empty());

    EverMadeChange |= OptimizeImpDefsBlock(MBB);

  }
@@ -434,7 +434,7 @@ static void FixTail(MachineBasicBlock* CurMBB, MachineBasicBlock *SuccBB, 
  MachineBasicBlock *TBB = 0, *FBB = 0;

  SmallVector<MachineOperand, 4> Cond;

  if (I != MF->end() &&

      !TII->AnalyzeBranch(*CurMBB, TBB, FBB, Cond)) {

      !TII->AnalyzeBranch(*CurMBB, TBB, FBB, Cond, true)) {

    MachineBasicBlock *NextBB = I;

    if (TBB == NextBB && !Cond.empty() && !FBB) {

      if (!TII->ReverseBranchCondition(Cond)) {
@@ -711,7 +711,7 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) { 
          continue;

        MachineBasicBlock *TBB = 0, *FBB = 0;

        SmallVector<MachineOperand, 4> Cond;

        if (!TII->AnalyzeBranch(*PBB, TBB, FBB, Cond)) {

        if (!TII->AnalyzeBranch(*PBB, TBB, FBB, Cond, true)) {

          // Failing case:  IBB is the target of a cbr, and

          // we cannot reverse the branch.

          SmallVector<MachineOperand, 4> NewCond(Cond);
@@ -845,7 +845,7 @@ bool BranchFolder::CanFallThrough(MachineBasicBlock *CurBB, 
bool BranchFolder::CanFallThrough(MachineBasicBlock *CurBB) {

  MachineBasicBlock *TBB = 0, *FBB = 0;

  SmallVector<MachineOperand, 4> Cond;

  bool CurUnAnalyzable = TII->AnalyzeBranch(*CurBB, TBB, FBB, Cond);

  bool CurUnAnalyzable = TII->AnalyzeBranch(*CurBB, TBB, FBB, Cond, true);

  return CanFallThrough(CurBB, CurUnAnalyzable, TBB, FBB, Cond);

}
@@ -910,7 +910,7 @@ void BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) { 
  MachineBasicBlock *PriorTBB = 0, *PriorFBB = 0;

  SmallVector<MachineOperand, 4> PriorCond;

  bool PriorUnAnalyzable =

    TII->AnalyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond);

    TII->AnalyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, true);

  if (!PriorUnAnalyzable) {

    // If the CFG for the prior block has extra edges, remove them.

    MadeChange |= PrevBB.CorrectExtraCFGEdges(PriorTBB, PriorFBB,
@@ -1023,7 +1023,7 @@ void BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) { 
  // Analyze the branch in the current block.

  MachineBasicBlock *CurTBB = 0, *CurFBB = 0;

  SmallVector<MachineOperand, 4> CurCond;

  bool CurUnAnalyzable = TII->AnalyzeBranch(*MBB, CurTBB, CurFBB, CurCond);

  bool CurUnAnalyzable= TII->AnalyzeBranch(*MBB, CurTBB, CurFBB, CurCond, true);

  if (!CurUnAnalyzable) {

    // If the CFG for the prior block has extra edges, remove them.

    MadeChange |= MBB->CorrectExtraCFGEdges(CurTBB, CurFBB, !CurCond.empty());

llvm/lib/Target/ARM/ARMInstrInfo.cpp

+6 −3
Original line number Diff line number Diff line
@@ -338,7 +338,8 @@ ARMInstrInfo::convertToThreeAddress(MachineFunction::iterator &MFI, 
// Branch analysis.

bool ARMInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,

                                 MachineBasicBlock *&FBB,

                                 SmallVectorImpl<MachineOperand> &Cond) const {

                                 SmallVectorImpl<MachineOperand> &Cond,

                                 bool AllowModify) const {

  // If the block has no terminators, it just falls into the block after it.

  MachineBasicBlock::iterator I = MBB.end();

  if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
@@ -388,6 +389,7 @@ bool ARMInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB, 
      (LastOpc == ARM::B || LastOpc == ARM::tB)) {

    TBB = SecondLastInst->getOperand(0).getMBB();

    I = LastInst;

    if (AllowModify)

      I->eraseFromParent();

    return false;

  }
@@ -399,6 +401,7 @@ bool ARMInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB, 
       SecondLastOpc == ARM::BR_JTadd || SecondLastOpc==ARM::tBR_JTr) &&

      (LastOpc == ARM::B || LastOpc == ARM::tB)) {

    I = LastInst;

    if (AllowModify)

      I->eraseFromParent();

    return true;

  }

llvm/lib/Target/ARM/ARMInstrInfo.h

+2 −1
Original line number Diff line number Diff line
@@ -176,7 +176,8 @@ public: 
  // Branch analysis.

  virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,

                             MachineBasicBlock *&FBB,

                             SmallVectorImpl<MachineOperand> &Cond) const;

                             SmallVectorImpl<MachineOperand> &Cond,

                             bool AllowModify) const;

  virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const;

  virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,

                                MachineBasicBlock *FBB,

llvm/lib/Target/Alpha/AlphaInstrInfo.cpp

+5 −3
Original line number Diff line number Diff line
@@ -322,7 +322,8 @@ static unsigned AlphaRevCondCode(unsigned Opcode) { 
// Branch analysis.

bool AlphaInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,

                                   MachineBasicBlock *&FBB,

                                 SmallVectorImpl<MachineOperand> &Cond) const {

                                   SmallVectorImpl<MachineOperand> &Cond,

                                   bool AllowModify) const {

  // If the block has no terminators, it just falls into the block after it.

  MachineBasicBlock::iterator I = MBB.end();

  if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
@@ -373,6 +374,7 @@ bool AlphaInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TB 
      LastInst->getOpcode() == Alpha::BR) {

    TBB = SecondLastInst->getOperand(0).getMBB();

    I = LastInst;

    if (AllowModify)

      I->eraseFromParent();

    return false;

  }