From 7707a0df5b00c8326a581205639d6b2871f182e9 Mon Sep 17 00:00:00 2001 From: Jim Grosbach Date: Thu, 12 Nov 2009 03:55:33 +0000 Subject: [PATCH] Move the utility function UpdateTerminator() from CodePlacementOpt() into MachineBasicBlock so other passes can utilize it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86947 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/MachineBasicBlock.h | 8 ++- lib/CodeGen/CodePlacementOpt.cpp | 64 ++---------------------- lib/CodeGen/MachineBasicBlock.cpp | 53 ++++++++++++++++++++ 3 files changed, 63 insertions(+), 62 deletions(-) diff --git a/include/llvm/CodeGen/MachineBasicBlock.h b/include/llvm/CodeGen/MachineBasicBlock.h index 95fd6a4ec6b..b11adfe3c71 100644 --- a/include/llvm/CodeGen/MachineBasicBlock.h +++ b/include/llvm/CodeGen/MachineBasicBlock.h @@ -225,7 +225,13 @@ public: /// potential fall-throughs at the end of the block. void moveBefore(MachineBasicBlock *NewAfter); void moveAfter(MachineBasicBlock *NewBefore); - + + /// updateTerminator - Update the terminator instructions in block 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 updateTerminator(); + // Machine-CFG mutators /// addSuccessor - Add succ as a successor of this MachineBasicBlock. diff --git a/lib/CodeGen/CodePlacementOpt.cpp b/lib/CodeGen/CodePlacementOpt.cpp index 6fff12c0b0d..e9844d84c17 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 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 diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index 14d66821bb9..7b14a4c8513 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -17,6 +17,7 @@ #include "llvm/Target/TargetRegisterInfo.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetInstrDesc.h" +#include "llvm/Target/TargetInstrInfo.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Support/LeakDetector.h" #include "llvm/Support/raw_ostream.h" @@ -242,6 +243,58 @@ void MachineBasicBlock::moveAfter(MachineBasicBlock *NewBefore) { getParent()->splice(++BBI, this); } +void MachineBasicBlock::updateTerminator() { + const TargetInstrInfo *TII = getParent()->getTarget().getInstrInfo(); + // A block with no successors has no concerns with fall-through edges. + if (this->succ_empty()) return; + + MachineBasicBlock *TBB = 0, *FBB = 0; + SmallVector Cond; + bool B = TII->AnalyzeBranch(*this, 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 (isLayoutSuccessor(TBB)) + TII->RemoveBranch(*this); + } else { + // The block has an unconditional fallthrough. If its successor is not + // its layout successor, insert a branch. + TBB = *succ_begin(); + if (!isLayoutSuccessor(TBB)) + TII->InsertBranch(*this, 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 (isLayoutSuccessor(TBB)) { + TII->RemoveBranch(*this); + TII->ReverseBranchCondition(Cond); + TII->InsertBranch(*this, FBB, 0, Cond); + } else if (isLayoutSuccessor(FBB)) { + TII->RemoveBranch(*this); + TII->InsertBranch(*this, TBB, 0, Cond); + } + } else { + // The block has a fallthrough conditional branch. + MachineBasicBlock *MBBA = *succ_begin(); + MachineBasicBlock *MBBB = *next(succ_begin()); + if (MBBA == TBB) std::swap(MBBB, MBBA); + if (isLayoutSuccessor(TBB)) { + TII->RemoveBranch(*this); + TII->ReverseBranchCondition(Cond); + TII->InsertBranch(*this, MBBA, 0, Cond); + } else if (!isLayoutSuccessor(MBBA)) { + TII->RemoveBranch(*this); + TII->InsertBranch(*this, TBB, MBBA, Cond); + } + } + } +} void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ) { Successors.push_back(succ); -- 2.34.1