diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/LoopUnswitch.cpp | 127 |
1 files changed, 0 insertions, 127 deletions
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp index 59aff31..c4ebfd5 100644 --- a/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -212,8 +212,6 @@ namespace { Instruction *InsertPt); void SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L); - void RemoveBlockIfDead(BasicBlock *BB, - std::vector<Instruction*> &Worklist, Loop *l); void RemoveLoopFromHierarchy(Loop *L); bool IsTrivialUnswitchCondition(Value *Cond, Constant **Val = 0, BasicBlock **LoopExit = 0); @@ -946,114 +944,6 @@ static void ReplaceUsesOfWith(Instruction *I, Value *V, ++NumSimplify; } -/// RemoveBlockIfDead - If the specified block is dead, remove it, update loop -/// information, and remove any dead successors it has. -/// -void LoopUnswitch::RemoveBlockIfDead(BasicBlock *BB, - std::vector<Instruction*> &Worklist, - Loop *L) { - if (pred_begin(BB) != pred_end(BB)) { - // This block isn't dead, since an edge to BB was just removed, see if there - // are any easy simplifications we can do now. - if (BasicBlock *Pred = BB->getSinglePredecessor()) { - // If it has one pred, fold phi nodes in BB. - while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) - ReplaceUsesOfWith(PN, PN->getIncomingValue(0), Worklist, L, LPM); - - // If this is the header of a loop and the only pred is the latch, we now - // have an unreachable loop. - if (Loop *L = LI->getLoopFor(BB)) - if (loopHeader == BB && L->contains(Pred)) { - // Remove the branch from the latch to the header block, this makes - // the header dead, which will make the latch dead (because the header - // dominates the latch). - LPM->deleteSimpleAnalysisValue(Pred->getTerminator(), L); - Pred->getTerminator()->eraseFromParent(); - new UnreachableInst(BB->getContext(), Pred); - - // The loop is now broken, remove it from LI. - RemoveLoopFromHierarchy(L); - - // Reprocess the header, which now IS dead. - RemoveBlockIfDead(BB, Worklist, L); - return; - } - - // If pred ends in a uncond branch, add uncond branch to worklist so that - // the two blocks will get merged. - if (BranchInst *BI = dyn_cast<BranchInst>(Pred->getTerminator())) - if (BI->isUnconditional()) - Worklist.push_back(BI); - } - return; - } - - DEBUG(dbgs() << "Nuking dead block: " << *BB); - - // Remove the instructions in the basic block from the worklist. - for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { - RemoveFromWorklist(I, Worklist); - - // Anything that uses the instructions in this basic block should have their - // uses replaced with undefs. - // If I is not void type then replaceAllUsesWith undef. - // This allows ValueHandlers and custom metadata to adjust itself. - if (!I->getType()->isVoidTy()) - I->replaceAllUsesWith(UndefValue::get(I->getType())); - } - - // If this is the edge to the header block for a loop, remove the loop and - // promote all subloops. - if (Loop *BBLoop = LI->getLoopFor(BB)) { - if (BBLoop->getLoopLatch() == BB) { - RemoveLoopFromHierarchy(BBLoop); - if (currentLoop == BBLoop) { - currentLoop = 0; - redoLoop = false; - } - } - } - - // Remove the block from the loop info, which removes it from any loops it - // was in. - LI->removeBlock(BB); - - // Remove phi node entries in successors for this block. - TerminatorInst *TI = BB->getTerminator(); - SmallVector<BasicBlock*, 4> Succs; - for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) { - Succs.push_back(TI->getSuccessor(i)); - TI->getSuccessor(i)->removePredecessor(BB); - } - - // Unique the successors, remove anything with multiple uses. - array_pod_sort(Succs.begin(), Succs.end()); - Succs.erase(std::unique(Succs.begin(), Succs.end()), Succs.end()); - - // Remove the basic block, including all of the instructions contained in it. - LPM->deleteSimpleAnalysisValue(BB, L); - BB->eraseFromParent(); - // Remove successor blocks here that are not dead, so that we know we only - // have dead blocks in this list. Nondead blocks have a way of becoming dead, - // then getting removed before we revisit them, which is badness. - // - for (unsigned i = 0; i != Succs.size(); ++i) - if (pred_begin(Succs[i]) != pred_end(Succs[i])) { - // One exception is loop headers. If this block was the preheader for a - // loop, then we DO want to visit the loop so the loop gets deleted. - // We know that if the successor is a loop header, that this loop had to - // be the preheader: the case where this was the latch block was handled - // above and headers can only have two predecessors. - if (!LI->isLoopHeader(Succs[i])) { - Succs.erase(Succs.begin()+i); - --i; - } - } - - for (unsigned i = 0, e = Succs.size(); i != e; ++i) - RemoveBlockIfDead(Succs[i], Worklist, L); -} - /// RemoveLoopFromHierarchy - We have discovered that the specified loop has /// become unwrapped, either because the backedge was deleted, or because the /// edge into the header was removed. If the edge into the header from the @@ -1262,23 +1152,6 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) { continue; } - if (ConstantInt *CB = dyn_cast<ConstantInt>(BI->getCondition())){ - // Conditional branch. Turn it into an unconditional branch, then - // remove dead blocks. - continue; // FIXME: Enable. - - DEBUG(dbgs() << "Folded branch: " << *BI); - BasicBlock *DeadSucc = BI->getSuccessor(CB->getZExtValue()); - BasicBlock *LiveSucc = BI->getSuccessor(!CB->getZExtValue()); - DeadSucc->removePredecessor(BI->getParent(), true); - Worklist.push_back(BranchInst::Create(LiveSucc, BI)); - LPM->deleteSimpleAnalysisValue(BI, L); - BI->eraseFromParent(); - RemoveFromWorklist(BI, Worklist); - ++NumSimplify; - - RemoveBlockIfDead(DeadSucc, Worklist, L); - } continue; } } |