diff options
Diffstat (limited to 'lib/CodeGen/CodePlacementOpt.cpp')
-rw-r--r-- | lib/CodeGen/CodePlacementOpt.cpp | 64 |
1 files changed, 3 insertions, 61 deletions
diff --git a/lib/CodeGen/CodePlacementOpt.cpp b/lib/CodeGen/CodePlacementOpt.cpp index 6fff12c..e9844d8 100644 --- a/lib/CodeGen/CodePlacementOpt.cpp +++ b/lib/CodeGen/CodePlacementOpt.cpp @@ -56,7 +56,6 @@ namespace { MachineFunction::iterator InsertPt, MachineFunction::iterator Begin, MachineFunction::iterator End); - void UpdateTerminator(MachineBasicBlock *MBB); bool EliminateUnconditionalJumpsToTop(MachineFunction &MF, MachineLoop *L); bool MoveDiscontiguousLoopBlocks(MachineFunction &MF, @@ -141,66 +140,9 @@ void CodePlacementOpt::Splice(MachineFunction &MF, MF.splice(InsertPt, Begin, End); - UpdateTerminator(prior(Begin)); - UpdateTerminator(OldBeginPrior); - UpdateTerminator(OldEndPrior); -} - -/// UpdateTerminator - Update the terminator instructions in MBB to account -/// for changes to the layout. If the block previously used a fallthrough, -/// it may now need a branch, and if it previously used branching it may now -/// be able to use a fallthrough. -/// -void CodePlacementOpt::UpdateTerminator(MachineBasicBlock *MBB) { - // A block with no successors has no concerns with fall-through edges. - if (MBB->succ_empty()) return; - - MachineBasicBlock *TBB = 0, *FBB = 0; - SmallVector<MachineOperand, 4> Cond; - bool B = TII->AnalyzeBranch(*MBB, TBB, FBB, Cond); - (void) B; - assert(!B && "UpdateTerminators requires analyzable predecessors!"); - if (Cond.empty()) { - if (TBB) { - // The block has an unconditional branch. If its successor is now - // its layout successor, delete the branch. - if (MBB->isLayoutSuccessor(TBB)) - TII->RemoveBranch(*MBB); - } else { - // The block has an unconditional fallthrough. If its successor is not - // its layout successor, insert a branch. - TBB = *MBB->succ_begin(); - if (!MBB->isLayoutSuccessor(TBB)) - TII->InsertBranch(*MBB, TBB, 0, Cond); - } - } else { - if (FBB) { - // The block has a non-fallthrough conditional branch. If one of its - // successors is its layout successor, rewrite it to a fallthrough - // conditional branch. - if (MBB->isLayoutSuccessor(TBB)) { - TII->RemoveBranch(*MBB); - TII->ReverseBranchCondition(Cond); - TII->InsertBranch(*MBB, FBB, 0, Cond); - } else if (MBB->isLayoutSuccessor(FBB)) { - TII->RemoveBranch(*MBB); - TII->InsertBranch(*MBB, TBB, 0, Cond); - } - } else { - // The block has a fallthrough conditional branch. - MachineBasicBlock *MBBA = *MBB->succ_begin(); - MachineBasicBlock *MBBB = *next(MBB->succ_begin()); - if (MBBA == TBB) std::swap(MBBB, MBBA); - if (MBB->isLayoutSuccessor(TBB)) { - TII->RemoveBranch(*MBB); - TII->ReverseBranchCondition(Cond); - TII->InsertBranch(*MBB, MBBA, 0, Cond); - } else if (!MBB->isLayoutSuccessor(MBBA)) { - TII->RemoveBranch(*MBB); - TII->InsertBranch(*MBB, TBB, MBBA, Cond); - } - } - } + prior(Begin)->updateTerminator(); + OldBeginPrior->updateTerminator(); + OldEndPrior->updateTerminator(); } /// EliminateUnconditionalJumpsToTop - Move blocks which unconditionally jump |