From 73db975498bc0e117a0854ab2e0cecad51ad17bf Mon Sep 17 00:00:00 2001 From: Jakub Staszak Date: Wed, 21 Dec 2011 20:18:54 +0000 Subject: - Change a few operator[] to lookup which is cheaper. - Add some constantness. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147090 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineBlockPlacement.cpp | 88 +++++++++++++++++------------------ 1 file changed, 43 insertions(+), 45 deletions(-) (limited to 'lib/CodeGen/MachineBlockPlacement.cpp') diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp index 638d895770..d874f2aabe 100644 --- a/lib/CodeGen/MachineBlockPlacement.cpp +++ b/lib/CodeGen/MachineBlockPlacement.cpp @@ -116,7 +116,7 @@ public: /// a contiguous sequence of basic blocks, updating the edge list, and /// updating the block -> chain mapping. It does not free or tear down the /// old chain, but the old chain's block list is no longer valid. - void merge(MachineBasicBlock *BB, BlockChain *Chain) { + void merge(MachineBasicBlock *BB, const BlockChain *Chain) { assert(BB); assert(!Blocks.empty()); @@ -185,28 +185,27 @@ class MachineBlockPlacement : public MachineFunctionPass { /// between basic blocks. DenseMap BlockToChain; - void markChainSuccessors(BlockChain &Chain, - MachineBasicBlock *LoopHeaderBB, + void markChainSuccessors(const BlockChain &Chain, + const MachineBasicBlock *LoopHeaderBB, SmallVectorImpl &BlockWorkList, - const BlockFilterSet *BlockFilter = 0); - MachineBasicBlock *selectBestSuccessor(MachineBasicBlock *BB, - BlockChain &Chain, - const BlockFilterSet *BlockFilter); + const BlockFilterSet *BlockFilter = 0) const; + MachineBasicBlock *selectBestSuccessor(const MachineBasicBlock *BB, + const BlockChain &Chain, const BlockFilterSet *BlockFilter) const; MachineBasicBlock *selectBestCandidateBlock( - BlockChain &Chain, SmallVectorImpl &WorkList, - const BlockFilterSet *BlockFilter); + const BlockChain &Chain, SmallVectorImpl &WorkList, + const BlockFilterSet *BlockFilter) const; MachineBasicBlock *getFirstUnplacedBlock( MachineFunction &F, const BlockChain &PlacedChain, MachineFunction::iterator &PrevUnplacedBlockIt, - const BlockFilterSet *BlockFilter); + const BlockFilterSet *BlockFilter) const; void buildChain(MachineBasicBlock *BB, BlockChain &Chain, SmallVectorImpl &BlockWorkList, - const BlockFilterSet *BlockFilter = 0); + const BlockFilterSet *BlockFilter = 0) const; MachineBasicBlock *findBestLoopTop(MachineFunction &F, MachineLoop &L, - const BlockFilterSet &LoopBlockSet); - void buildLoopChains(MachineFunction &F, MachineLoop &L); + const BlockFilterSet &LoopBlockSet) const; + void buildLoopChains(MachineFunction &F, MachineLoop &L) const; void buildCFGChains(MachineFunction &F); void AlignLoops(MachineFunction &F); @@ -246,7 +245,7 @@ FunctionPass *llvm::createMachineBlockPlacementPass() { /// \brief Helper to print the name of a MBB. /// /// Only used by debug logging. -static std::string getBlockName(MachineBasicBlock *BB) { +static std::string getBlockName(const MachineBasicBlock *BB) { std::string Result; raw_string_ostream OS(Result); OS << "BB#" << BB->getNumber() @@ -258,7 +257,7 @@ static std::string getBlockName(MachineBasicBlock *BB) { /// \brief Helper to print the number of a MBB. /// /// Only used by debug logging. -static std::string getBlockNum(MachineBasicBlock *BB) { +static std::string getBlockNum(const MachineBasicBlock *BB) { std::string Result; raw_string_ostream OS(Result); OS << "BB#" << BB->getNumber(); @@ -274,10 +273,10 @@ static std::string getBlockNum(MachineBasicBlock *BB) { /// having one fewer active predecessor. It also adds any successors of this /// chain which reach the zero-predecessor state to the worklist passed in. void MachineBlockPlacement::markChainSuccessors( - BlockChain &Chain, - MachineBasicBlock *LoopHeaderBB, + const BlockChain &Chain, + const MachineBasicBlock *LoopHeaderBB, SmallVectorImpl &BlockWorkList, - const BlockFilterSet *BlockFilter) { + const BlockFilterSet *BlockFilter) const { // Walk all the blocks in this chain, marking their successors as having // a predecessor placed. for (BlockChain::iterator CBI = Chain.begin(), CBE = Chain.end(); @@ -291,7 +290,7 @@ void MachineBlockPlacement::markChainSuccessors( SI != SE; ++SI) { if (BlockFilter && !BlockFilter->count(*SI)) continue; - BlockChain &SuccChain = *BlockToChain[*SI]; + BlockChain &SuccChain = *BlockToChain.lookup(*SI); // Disregard edges within a fixed chain, or edges to the loop header. if (&Chain == &SuccChain || *SI == LoopHeaderBB) continue; @@ -314,8 +313,8 @@ void MachineBlockPlacement::markChainSuccessors( /// /// \returns The best successor block found, or null if none are viable. MachineBasicBlock *MachineBlockPlacement::selectBestSuccessor( - MachineBasicBlock *BB, BlockChain &Chain, - const BlockFilterSet *BlockFilter) { + const MachineBasicBlock *BB, const BlockChain &Chain, + const BlockFilterSet *BlockFilter) const { const BranchProbability HotProb(4, 5); // 80% MachineBasicBlock *BestSucc = 0; @@ -329,12 +328,11 @@ MachineBasicBlock *MachineBlockPlacement::selectBestSuccessor( uint32_t WeightScale = 0; uint32_t SumWeight = MBPI->getSumForBlock(BB, WeightScale); DEBUG(dbgs() << "Attempting merge from: " << getBlockName(BB) << "\n"); - for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(), - SE = BB->succ_end(); - SI != SE; ++SI) { + for (MachineBasicBlock::const_succ_iterator SI = BB->succ_begin(), + SE = BB->succ_end(); SI != SE; ++SI) { if (BlockFilter && !BlockFilter->count(*SI)) continue; - BlockChain &SuccChain = *BlockToChain[*SI]; + const BlockChain &SuccChain = *BlockToChain.lookup(*SI); if (&SuccChain == &Chain) { DEBUG(dbgs() << " " << getBlockName(*SI) << " -> Already merged!\n"); continue; @@ -364,7 +362,7 @@ MachineBasicBlock *MachineBlockPlacement::selectBestSuccessor( PE = (*SI)->pred_end(); PI != PE; ++PI) { if (*PI == *SI || (BlockFilter && !BlockFilter->count(*PI)) || - BlockToChain[*PI] == &Chain) + BlockToChain.lookup(*PI) == &Chain) continue; BlockFrequency PredEdgeFreq = MBFI->getBlockFreq(*PI) * MBPI->getEdgeProbability(*PI, *SI); @@ -420,8 +418,8 @@ public: /// /// \returns The best block found, or null if none are viable. MachineBasicBlock *MachineBlockPlacement::selectBestCandidateBlock( - BlockChain &Chain, SmallVectorImpl &WorkList, - const BlockFilterSet *BlockFilter) { + const BlockChain &Chain, SmallVectorImpl &WorkList, + const BlockFilterSet *BlockFilter) const { // Once we need to walk the worklist looking for a candidate, cleanup the // worklist of already placed entries. // FIXME: If this shows up on profiles, it could be folded (at the cost of @@ -436,7 +434,7 @@ MachineBasicBlock *MachineBlockPlacement::selectBestCandidateBlock( WBE = WorkList.end(); WBI != WBE; ++WBI) { assert(!BlockFilter || BlockFilter->count(*WBI)); - BlockChain &SuccChain = *BlockToChain[*WBI]; + const BlockChain &SuccChain = *BlockToChain.lookup(*WBI); if (&SuccChain == &Chain) { DEBUG(dbgs() << " " << getBlockName(*WBI) << " -> Already merged!\n"); @@ -465,17 +463,17 @@ MachineBasicBlock *MachineBlockPlacement::selectBestCandidateBlock( MachineBasicBlock *MachineBlockPlacement::getFirstUnplacedBlock( MachineFunction &F, const BlockChain &PlacedChain, MachineFunction::iterator &PrevUnplacedBlockIt, - const BlockFilterSet *BlockFilter) { + const BlockFilterSet *BlockFilter) const { for (MachineFunction::iterator I = PrevUnplacedBlockIt, E = F.end(); I != E; ++I) { if (BlockFilter && !BlockFilter->count(I)) continue; - if (BlockToChain[I] != &PlacedChain) { + if (BlockToChain.lookup(I) != &PlacedChain) { PrevUnplacedBlockIt = I; // Now select the head of the chain to which the unplaced block belongs // as the block to place. This will force the entire chain to be placed, // and satisfies the requirements of merging chains. - return *BlockToChain[I]->begin(); + return *BlockToChain.lookup(I)->begin(); } } return 0; @@ -485,9 +483,9 @@ void MachineBlockPlacement::buildChain( MachineBasicBlock *BB, BlockChain &Chain, SmallVectorImpl &BlockWorkList, - const BlockFilterSet *BlockFilter) { + const BlockFilterSet *BlockFilter) const { assert(BB); - assert(BlockToChain[BB] == &Chain); + assert(BlockToChain.lookup(BB) == &Chain); MachineFunction &F = *BB->getParent(); MachineFunction::iterator PrevUnplacedBlockIt = F.begin(); @@ -496,7 +494,7 @@ void MachineBlockPlacement::buildChain( BB = *llvm::prior(Chain.end()); for (;;) { assert(BB); - assert(BlockToChain[BB] == &Chain); + assert(BlockToChain.lookup(BB) == &Chain); assert(*llvm::prior(Chain.end()) == BB); MachineBasicBlock *BestSucc = 0; @@ -521,7 +519,7 @@ void MachineBlockPlacement::buildChain( } // Place this block, updating the datastructures to reflect its placement. - BlockChain &SuccChain = *BlockToChain[BestSucc]; + BlockChain &SuccChain = *BlockToChain.lookup(BestSucc); // Zero out LoopPredecessors for the successor we're about to merge in case // we selected a successor that didn't fit naturally into the CFG. SuccChain.LoopPredecessors = 0; @@ -544,7 +542,7 @@ void MachineBlockPlacement::buildChain( MachineBasicBlock * MachineBlockPlacement::findBestLoopTop(MachineFunction &F, MachineLoop &L, - const BlockFilterSet &LoopBlockSet) { + const BlockFilterSet &LoopBlockSet) const { BlockFrequency BestExitEdgeFreq; MachineBasicBlock *ExitingBB = 0; MachineBasicBlock *LoopingBB = 0; @@ -558,7 +556,7 @@ MachineBlockPlacement::findBestLoopTop(MachineFunction &F, for (MachineLoop::block_iterator I = L.block_begin(), E = L.block_end(); I != E; ++I) { - BlockChain &Chain = *BlockToChain[*I]; + const BlockChain &Chain = *BlockToChain.lookup(*I); // Ensure that this block is at the end of a chain; otherwise it could be // mid-way through an inner loop or a successor of an analyzable branch. if (*I != *llvm::prior(Chain.end())) @@ -588,7 +586,7 @@ MachineBlockPlacement::findBestLoopTop(MachineFunction &F, continue; if (*SI == *I) continue; - BlockChain &SuccChain = *BlockToChain[*SI]; + const BlockChain &SuccChain = *BlockToChain.lookup(*SI); // Don't split chains, either this chain or the successor's chain. if (&Chain == &SuccChain || *SI != *SuccChain.begin()) { DEBUG(dbgs() << " " << (LoopBlockSet.count(*SI) ? "looping: " @@ -665,7 +663,7 @@ MachineBlockPlacement::findBestLoopTop(MachineFunction &F, /// both preserves the topological structure and minimizes taken conditional /// branches. void MachineBlockPlacement::buildLoopChains(MachineFunction &F, - MachineLoop &L) { + MachineLoop &L) const { // First recurse through any nested loops, building chains for those inner // loops. for (MachineLoop::iterator LI = L.begin(), LE = L.end(); LI != LE; ++LI) @@ -675,29 +673,29 @@ void MachineBlockPlacement::buildLoopChains(MachineFunction &F, BlockFilterSet LoopBlockSet(L.block_begin(), L.block_end()); MachineBasicBlock *LayoutTop = findBestLoopTop(F, L, LoopBlockSet); - BlockChain &LoopChain = *BlockToChain[LayoutTop]; + BlockChain &LoopChain = *BlockToChain.lookup(LayoutTop); // FIXME: This is a really lame way of walking the chains in the loop: we // walk the blocks, and use a set to prevent visiting a particular chain // twice. - SmallPtrSet UpdatedPreds; + SmallPtrSet UpdatedPreds; assert(LoopChain.LoopPredecessors == 0); UpdatedPreds.insert(&LoopChain); for (MachineLoop::block_iterator BI = L.block_begin(), BE = L.block_end(); BI != BE; ++BI) { - BlockChain &Chain = *BlockToChain[*BI]; + BlockChain &Chain = *BlockToChain.lookup(*BI); if (!UpdatedPreds.insert(&Chain)) continue; assert(Chain.LoopPredecessors == 0); for (BlockChain::iterator BCI = Chain.begin(), BCE = Chain.end(); BCI != BCE; ++BCI) { - assert(BlockToChain[*BCI] == &Chain); + assert(BlockToChain.lookup(*BCI) == &Chain); for (MachineBasicBlock::pred_iterator PI = (*BCI)->pred_begin(), PE = (*BCI)->pred_end(); PI != PE; ++PI) { - if (BlockToChain[*PI] == &Chain || !LoopBlockSet.count(*PI)) + if (BlockToChain.lookup(*PI) == &Chain || !LoopBlockSet.count(*PI)) continue; ++Chain.LoopPredecessors; } -- cgit v1.2.3