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Update LoopUnswitch pass to preserve DomiantorTree.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37771 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -35,6 +35,7 @@
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#include "llvm/Analysis/ConstantFolding.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Analysis/LoopPass.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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@ -82,6 +83,7 @@ namespace {
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequiredID(LoopSimplifyID);
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AU.addPreservedID(LoopSimplifyID);
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AU.addPreserved<DominatorTree>();
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AU.addRequired<LoopInfo>();
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AU.addPreserved<LoopInfo>();
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AU.addRequiredID(LCSSAID);
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@ -109,6 +111,11 @@ namespace {
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void RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
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Constant *Val, bool isEqual);
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void EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
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BasicBlock *TrueDest,
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BasicBlock *FalseDest,
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Instruction *InsertPt);
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void SimplifyCode(std::vector<Instruction*> &Worklist);
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void RemoveBlockIfDead(BasicBlock *BB,
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std::vector<Instruction*> &Worklist);
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@ -413,6 +420,9 @@ BasicBlock *LoopUnswitch::SplitBlock(BasicBlock *Old, Instruction *SplitPt) {
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if (Loop *L = LI->getLoopFor(Old))
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L->addBasicBlockToLoop(New, *LI);
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if (DominatorTree *DT = getAnalysisToUpdate<DominatorTree>())
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DT->addNewBlock(New, Old);
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return New;
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}
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@ -429,30 +439,8 @@ BasicBlock *LoopUnswitch::SplitEdge(BasicBlock *BB, BasicBlock *Succ) {
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}
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// If this is a critical edge, let SplitCriticalEdge do it.
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Loop *OrigDestBBL = LI->getLoopFor(BB->getTerminator()->getSuccessor(SuccNum));
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if (SplitCriticalEdge(BB->getTerminator(), SuccNum)) {
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BasicBlock *NewBB = LatchTerm->getSuccessor(SuccNum);
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Loop *BBL = LI->getLoopFor(BB);
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if (!BBL || !OrigDestBBL)
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return NewBB;
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// If edge is inside a loop then NewBB is part of same loop.
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if (BBL == OrigDestBBL)
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BBL->addBasicBlockToLoop(NewBB, *LI);
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// If edge is entering loop then NewBB is part of outer loop.
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else if (BBL->contains(OrigDestBBL->getHeader()))
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BBL->addBasicBlockToLoop(NewBB, *LI);
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// If edge is from an inner loop to outer loop then NewBB is part
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// of outer loop.
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else if (OrigDestBBL->contains(BBL->getHeader()))
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OrigDestBBL->addBasicBlockToLoop(NewBB, *LI);
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// Else edge is connecting two loops and NewBB is part of their parent loop
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else if (Loop *PL = OrigDestBBL->getParentLoop())
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PL->addBasicBlockToLoop(NewBB, *LI);
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return NewBB;
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}
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if (SplitCriticalEdge(BB->getTerminator(), SuccNum, this))
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return LatchTerm->getSuccessor(SuccNum);
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// If the edge isn't critical, then BB has a single successor or Succ has a
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// single pred. Split the block.
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@ -486,6 +474,26 @@ static inline void RemapInstruction(Instruction *I,
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}
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}
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// CloneDomInfo - NewBB is cloned from Orig basic block. Now clone Dominator Info.
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// If Orig is in Loop then find and use Orig dominator's cloned block as NewBB
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// dominator.
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void CloneDomInfo(BasicBlock *NewBB, BasicBlock *Orig, Loop *L,
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DominatorTree *DT,
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DenseMap<const Value*, Value*> &VM) {
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DomTreeNode *OrigNode = DT->getNode(Orig);
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if (!OrigNode)
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return;
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BasicBlock *OrigIDom = OrigNode->getBlock();
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BasicBlock *NewIDom = OrigIDom;
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if (L->contains(OrigIDom)) {
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if (!DT->getNode(OrigIDom))
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CloneDomInfo(NewIDom, OrigIDom, L, DT, VM);
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NewIDom = cast<BasicBlock>(VM[OrigIDom]);
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}
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DT->addNewBlock(NewBB, OrigIDom);
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}
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/// CloneLoop - Recursively clone the specified loop and all of its children,
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/// mapping the blocks with the specified map.
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static Loop *CloneLoop(Loop *L, Loop *PL, DenseMap<const Value*, Value*> &VM,
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@ -510,10 +518,10 @@ static Loop *CloneLoop(Loop *L, Loop *PL, DenseMap<const Value*, Value*> &VM,
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/// EmitPreheaderBranchOnCondition - Emit a conditional branch on two values
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/// if LIC == Val, branch to TrueDst, otherwise branch to FalseDest. Insert the
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/// code immediately before InsertPt.
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static void EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
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BasicBlock *TrueDest,
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BasicBlock *FalseDest,
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Instruction *InsertPt) {
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void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
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BasicBlock *TrueDest,
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BasicBlock *FalseDest,
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Instruction *InsertPt) {
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// Insert a conditional branch on LIC to the two preheaders. The original
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// code is the true version and the new code is the false version.
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Value *BranchVal = LIC;
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@ -524,7 +532,15 @@ static void EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
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std::swap(TrueDest, FalseDest);
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// Insert the new branch.
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new BranchInst(TrueDest, FalseDest, BranchVal, InsertPt);
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BranchInst *BRI = new BranchInst(TrueDest, FalseDest, BranchVal, InsertPt);
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// Update dominator info.
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if (DominatorTree *DT = getAnalysisToUpdate<DominatorTree>()) {
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// BranchVal is a new preheader so it dominates true and false destination
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// loop headers.
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DT->changeImmediateDominator(TrueDest, BRI->getParent());
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DT->changeImmediateDominator(FalseDest, BRI->getParent());
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}
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}
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@ -574,7 +590,6 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond,
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++NumTrivial;
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}
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/// VersionLoop - We determined that the loop is profitable to unswitch when LIC
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/// equal Val. Split it into loop versions and test the condition outside of
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/// either loop. Return the loops created as Out1/Out2.
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@ -666,6 +681,14 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
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ValueMap[LoopBlocks[i]] = New; // Keep the BB mapping.
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}
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// Update dominator info
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if (DominatorTree *DT = getAnalysisToUpdate<DominatorTree>())
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for (unsigned i = 0, e = LoopBlocks.size(); i != e; ++i) {
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BasicBlock *LBB = LoopBlocks[i];
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BasicBlock *NBB = NewBlocks[i];
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CloneDomInfo(NBB, LBB, L, DT, ValueMap);
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}
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// Splice the newly inserted blocks into the function right before the
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// original preheader.
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F->getBasicBlockList().splice(LoopBlocks[0], F->getBasicBlockList(),
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