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[MBP] NFC, run clang-format over this code and tweak things to make the

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result reasonable.

This code predated clang-format and so there was a reasonable amount of
crufty formatting that had accumulated. This should ensure that neither
myself nor others end up with formatting-only changes sneaking into
other fixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231341 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2015-03-05 02:35:31 +00:00
parent 559a329625
commit 35742dd20c
1 changed files with 62 additions and 71 deletions
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133
lib/CodeGen/MachineBlockPlacement.cpp
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@ -62,11 +62,11 @@ static cl::opt<unsigned> AlignAllBlock("align-all-blocks",
cl::init(0), cl::Hidden);
// FIXME: Find a good default for this flag and remove the flag.
static cl::opt<unsigned>
ExitBlockBias("block-placement-exit-block-bias",
cl::desc("Block frequency percentage a loop exit block needs "
"over the original exit to be considered the new exit."),
cl::init(0), cl::Hidden);
static cl::opt<unsigned> ExitBlockBias(
"block-placement-exit-block-bias",
cl::desc("Block frequency percentage a loop exit block needs "
"over the original exit to be considered the new exit."),
cl::init(0), cl::Hidden);
static cl::opt<bool> OutlineOptionalBranches(
"outline-optional-branches",
@ -114,7 +114,7 @@ public:
/// function. It also registers itself as the chain that block participates
/// in with the BlockToChain mapping.
BlockChain(BlockToChainMapType &BlockToChain, MachineBasicBlock *BB)
: Blocks(1, BB), BlockToChain(BlockToChain), LoopPredecessors(0) {
: Blocks(1, BB), BlockToChain(BlockToChain), LoopPredecessors(0) {
assert(BB && "Cannot create a chain with a null basic block");
BlockToChain[BB] = this;
}
@ -151,8 +151,8 @@ public:
// Update the incoming blocks to point to this chain, and add them to the
// chain structure.
for (BlockChain::iterator BI = Chain->begin(), BE = Chain->end();
BI != BE; ++BI) {
for (BlockChain::iterator BI = Chain->begin(), BE = Chain->end(); BI != BE;
++BI) {
Blocks.push_back(*BI);
assert(BlockToChain[*BI] == Chain && "Incoming blocks not in chain");
BlockToChain[*BI] = this;
@ -199,7 +199,7 @@ class MachineBlockPlacement : public MachineFunctionPass {
MachineDominatorTree *MDT;
/// \brief A set of blocks that are unavoidably execute, i.e. they dominate
/// all terminators of the MachineFunction.
/// all terminators of the MachineFunction.
SmallPtrSet<MachineBasicBlock *, 4> UnavoidableBlocks;
/// \brief Allocator and owner of BlockChain structures.
@ -219,28 +219,26 @@ class MachineBlockPlacement : public MachineFunctionPass {
/// between basic blocks.
DenseMap<MachineBasicBlock *, BlockChain *> BlockToChain;
void markChainSuccessors(BlockChain &Chain,
MachineBasicBlock *LoopHeaderBB,
void markChainSuccessors(BlockChain &Chain, MachineBasicBlock *LoopHeaderBB,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
const BlockFilterSet *BlockFilter = nullptr);
MachineBasicBlock *selectBestSuccessor(MachineBasicBlock *BB,
BlockChain &Chain,
const BlockFilterSet *BlockFilter);
MachineBasicBlock *selectBestCandidateBlock(
BlockChain &Chain, SmallVectorImpl<MachineBasicBlock *> &WorkList,
const BlockFilterSet *BlockFilter);
MachineBasicBlock *getFirstUnplacedBlock(
MachineFunction &F,
const BlockChain &PlacedChain,
MachineFunction::iterator &PrevUnplacedBlockIt,
const BlockFilterSet *BlockFilter);
MachineBasicBlock *
selectBestCandidateBlock(BlockChain &Chain,
SmallVectorImpl<MachineBasicBlock *> &WorkList,
const BlockFilterSet *BlockFilter);
MachineBasicBlock *
getFirstUnplacedBlock(MachineFunction &F, const BlockChain &PlacedChain,
MachineFunction::iterator &PrevUnplacedBlockIt,
const BlockFilterSet *BlockFilter);
void buildChain(MachineBasicBlock *BB, BlockChain &Chain,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
const BlockFilterSet *BlockFilter = nullptr);
MachineBasicBlock *findBestLoopTop(MachineLoop &L,
const BlockFilterSet &LoopBlockSet);
MachineBasicBlock *findBestLoopExit(MachineFunction &F,
MachineLoop &L,
MachineBasicBlock *findBestLoopExit(MachineFunction &F, MachineLoop &L,
const BlockFilterSet &LoopBlockSet);
void buildLoopChains(MachineFunction &F, MachineLoop &L);
void rotateLoop(BlockChain &LoopChain, MachineBasicBlock *ExitingBB,
@ -283,8 +281,8 @@ INITIALIZE_PASS_END(MachineBlockPlacement, "block-placement",
static std::string getBlockName(MachineBasicBlock *BB) {
std::string Result;
raw_string_ostream OS(Result);
OS << "BB#" << BB->getNumber()
<< " (derived from LLVM BB '" << BB->getName() << "')";
OS << "BB#" << BB->getNumber();
OS << " (derived from LLVM BB '" << BB->getName() << "')";
OS.flush();
return Result;
}
@ -308,14 +306,13 @@ 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,
BlockChain &Chain, MachineBasicBlock *LoopHeaderBB,
SmallVectorImpl<MachineBasicBlock *> &BlockWorkList,
const BlockFilterSet *BlockFilter) {
// Walk all the blocks in this chain, marking their successors as having
// a predecessor placed.
for (BlockChain::iterator CBI = Chain.begin(), CBE = Chain.end();
CBI != CBE; ++CBI) {
for (BlockChain::iterator CBI = Chain.begin(), CBE = Chain.end(); CBI != CBE;
++CBI) {
// Add any successors for which this is the only un-placed in-loop
// predecessor to the worklist as a viable candidate for CFG-neutral
// placement. No subsequent placement of this block will violate the CFG
@ -347,9 +344,10 @@ void MachineBlockPlacement::markChainSuccessors(
/// very hot successor edges.
///
/// \returns The best successor block found, or null if none are viable.
MachineBasicBlock *MachineBlockPlacement::selectBestSuccessor(
MachineBasicBlock *BB, BlockChain &Chain,
const BlockFilterSet *BlockFilter) {
MachineBasicBlock *
MachineBlockPlacement::selectBestSuccessor(MachineBasicBlock *BB,
BlockChain &Chain,
const BlockFilterSet *BlockFilter) {
const BranchProbability HotProb(4, 5); // 80%
MachineBasicBlock *BestSucc = nullptr;
@ -449,8 +447,8 @@ MachineBasicBlock *MachineBlockPlacement::selectBestCandidateBlock(
// some code complexity) into the loop below.
WorkList.erase(std::remove_if(WorkList.begin(), WorkList.end(),
[&](MachineBasicBlock *BB) {
return BlockToChain.lookup(BB) == &Chain;
}),
return BlockToChain.lookup(BB) == &Chain;
}),
WorkList.end());
MachineBasicBlock *BestBlock = nullptr;
@ -460,15 +458,14 @@ MachineBasicBlock *MachineBlockPlacement::selectBestCandidateBlock(
WBI != WBE; ++WBI) {
BlockChain &SuccChain = *BlockToChain[*WBI];
if (&SuccChain == &Chain) {
DEBUG(dbgs() << " " << getBlockName(*WBI)
<< " -> Already merged!\n");
DEBUG(dbgs() << " " << getBlockName(*WBI) << " -> Already merged!\n");
continue;
}
assert(SuccChain.LoopPredecessors == 0 && "Found CFG-violating block");
BlockFrequency CandidateFreq = MBFI->getBlockFreq(*WBI);
DEBUG(dbgs() << " " << getBlockName(*WBI) << " -> ";
MBFI->printBlockFreq(dbgs(), CandidateFreq) << " (freq)\n");
MBFI->printBlockFreq(dbgs(), CandidateFreq) << " (freq)\n");
if (BestBlock && BestFreq >= CandidateFreq)
continue;
BestBlock = *WBI;
@ -531,8 +528,8 @@ void MachineBlockPlacement::buildChain(
BestSucc = selectBestCandidateBlock(Chain, BlockWorkList, BlockFilter);
if (!BestSucc) {
BestSucc = getFirstUnplacedBlock(F, Chain, PrevUnplacedBlockIt,
BlockFilter);
BestSucc =
getFirstUnplacedBlock(F, Chain, PrevUnplacedBlockIt, BlockFilter);
if (!BestSucc)
break;
@ -545,8 +542,8 @@ void MachineBlockPlacement::buildChain(
// 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;
DEBUG(dbgs() << "Merging from " << getBlockNum(BB)
<< " to " << getBlockNum(BestSucc) << "\n");
DEBUG(dbgs() << "Merging from " << getBlockNum(BB) << " to "
<< getBlockNum(BestSucc) << "\n");
markChainSuccessors(SuccChain, LoopHeaderBB, BlockWorkList, BlockFilter);
Chain.merge(BestSucc, &SuccChain);
BB = *std::prev(Chain.end());
@ -576,8 +573,8 @@ MachineBlockPlacement::findBestLoopTop(MachineLoop &L,
if (!LoopBlockSet.count(*HeaderChain.begin()))
return L.getHeader();
DEBUG(dbgs() << "Finding best loop top for: "
<< getBlockName(L.getHeader()) << "\n");
DEBUG(dbgs() << "Finding best loop top for: " << getBlockName(L.getHeader())
<< "\n");
BlockFrequency BestPredFreq;
MachineBasicBlock *BestPred = nullptr;
@ -589,7 +586,7 @@ MachineBlockPlacement::findBestLoopTop(MachineLoop &L,
continue;
DEBUG(dbgs() << " header pred: " << getBlockName(Pred) << ", "
<< Pred->succ_size() << " successors, ";
MBFI->printBlockFreq(dbgs(), Pred) << " freq\n");
MBFI->printBlockFreq(dbgs(), Pred) << " freq\n");
if (Pred->succ_size() > 1)
continue;
@ -616,15 +613,13 @@ MachineBlockPlacement::findBestLoopTop(MachineLoop &L,
return BestPred;
}
/// \brief Find the best loop exiting block for layout.
///
/// This routine implements the logic to analyze the loop looking for the best
/// block to layout at the top of the loop. Typically this is done to maximize
/// fallthrough opportunities.
MachineBasicBlock *
MachineBlockPlacement::findBestLoopExit(MachineFunction &F,
MachineLoop &L,
MachineBlockPlacement::findBestLoopExit(MachineFunction &F, MachineLoop &L,
const BlockFilterSet &LoopBlockSet) {
// We don't want to layout the loop linearly in all cases. If the loop header
// is just a normal basic block in the loop, we want to look for what block
@ -646,10 +641,9 @@ MachineBlockPlacement::findBestLoopExit(MachineFunction &F,
// blocks where rotating to exit with that block will reach an outer loop.
SmallPtrSet<MachineBasicBlock *, 4> BlocksExitingToOuterLoop;
DEBUG(dbgs() << "Finding best loop exit for: "
<< getBlockName(L.getHeader()) << "\n");
for (MachineLoop::block_iterator I = L.block_begin(),
E = L.block_end();
DEBUG(dbgs() << "Finding best loop exit for: " << getBlockName(L.getHeader())
<< "\n");
for (MachineLoop::block_iterator I = L.block_begin(), E = L.block_end();
I != E; ++I) {
BlockChain &Chain = *BlockToChain[*I];
// Ensure that this block is at the end of a chain; otherwise it could be
@ -702,9 +696,8 @@ MachineBlockPlacement::findBestLoopExit(MachineFunction &F,
BranchProbability SuccProb(SuccWeight / WeightScale, SumWeight);
BlockFrequency ExitEdgeFreq = MBFI->getBlockFreq(*I) * SuccProb;
DEBUG(dbgs() << " exiting: " << getBlockName(*I) << " -> "
<< getBlockName(*SI) << " [L:" << SuccLoopDepth
<< "] (";
MBFI->printBlockFreq(dbgs(), ExitEdgeFreq) << ")\n");
<< getBlockName(*SI) << " [L:" << SuccLoopDepth << "] (";
MBFI->printBlockFreq(dbgs(), ExitEdgeFreq) << ")\n");
// Note that we bias this toward an existing layout successor to retain
// incoming order in the absence of better information. The exit must have
// a frequency higher than the current exit before we consider breaking
@ -782,8 +775,8 @@ void MachineBlockPlacement::rotateLoop(BlockChain &LoopChain,
}
}
BlockChain::iterator ExitIt = std::find(LoopChain.begin(), LoopChain.end(),
ExitingBB);
BlockChain::iterator ExitIt =
std::find(LoopChain.begin(), LoopChain.end(), ExitingBB);
if (ExitIt == LoopChain.end())
return;
@ -827,8 +820,7 @@ void MachineBlockPlacement::buildLoopChains(MachineFunction &F,
SmallPtrSet<BlockChain *, 4> UpdatedPreds;
assert(LoopChain.LoopPredecessors == 0);
UpdatedPreds.insert(&LoopChain);
for (MachineLoop::block_iterator BI = L.block_begin(),
BE = L.block_end();
for (MachineLoop::block_iterator BI = L.block_begin(), BE = L.block_end();
BI != BE; ++BI) {
BlockChain &Chain = *BlockToChain[*BI];
if (!UpdatedPreds.insert(&Chain).second)
@ -897,8 +889,8 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
SmallVector<MachineOperand, 4> Cond; // For AnalyzeBranch.
for (MachineFunction::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) {
MachineBasicBlock *BB = FI;
BlockChain *Chain
= new (ChainAllocator.Allocate()) BlockChain(BlockToChain, BB);
BlockChain *Chain =
new (ChainAllocator.Allocate()) BlockChain(BlockToChain, BB);
// Also, merge any blocks which we cannot reason about and must preserve
// the exact fallthrough behavior for.
for (;;) {
@ -1012,8 +1004,8 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
BE = FunctionChain.end();
BI != BE; ++BI) {
DEBUG(dbgs() << (BI == FunctionChain.begin() ? "Placing chain "
: " ... ")
<< getBlockName(*BI) << "\n");
: " ... ")
<< getBlockName(*BI) << "\n");
if (InsertPos != MachineFunction::iterator(*BI))
F.splice(InsertPos, *BI);
else
@ -1032,9 +1024,9 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
if (!TII->AnalyzeBranch(*PrevBB, TBB, FBB, Cond)) {
// The "PrevBB" is not yet updated to reflect current code layout, so,
// o. it may fall-through to a block without explict "goto" instruction
// before layout, and no longer fall-through it after layout; or
// before layout, and no longer fall-through it after layout; or
// o. just opposite.
//
//
// AnalyzeBranch() may return erroneous value for FBB when these two
// situations take place. For the first scenario FBB is mistakenly set
// NULL; for the 2nd scenario, the FBB, which is expected to be NULL,
@ -1061,7 +1053,7 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
<< getBlockName(PrevBB) << "\n");
DEBUG(dbgs() << " Edge weight: " << MBPI->getEdgeWeight(PrevBB, FBB)
<< " vs " << MBPI->getEdgeWeight(PrevBB, TBB) << "\n");
DebugLoc dl; // FIXME: this is nowhere
DebugLoc dl; // FIXME: this is nowhere
TII->RemoveBranch(*PrevBB);
TII->InsertBranch(*PrevBB, FBB, TBB, Cond, dl);
needUpdateBr = true;
@ -1085,7 +1077,7 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
if (F.getFunction()->hasFnAttribute(Attribute::OptimizeForSize))
return;
if (FunctionChain.begin() == FunctionChain.end())
return; // Empty chain.
return; // Empty chain.
const BranchProbability ColdProb(1, 5); // 20%
BlockFrequency EntryFreq = MBFI->getBlockFreq(F.begin());
@ -1103,7 +1095,7 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
unsigned Align = TLI->getPrefLoopAlignment(L);
if (!Align)
continue; // Don't care about loop alignment.
continue; // Don't care about loop alignment.
// If the block is cold relative to the function entry don't waste space
// aligning it.
@ -1163,8 +1155,7 @@ bool MachineBlockPlacement::runOnMachineFunction(MachineFunction &F) {
if (AlignAllBlock)
// Align all of the blocks in the function to a specific alignment.
for (MachineFunction::iterator FI = F.begin(), FE = F.end();
FI != FE; ++FI)
for (MachineFunction::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
FI->setAlignment(AlignAllBlock);
// We always return true as we have no way to track whether the final order
@ -1222,10 +1213,10 @@ bool MachineBlockPlacementStats::runOnMachineFunction(MachineFunction &F) {
for (MachineFunction::iterator I = F.begin(), E = F.end(); I != E; ++I) {
BlockFrequency BlockFreq = MBFI->getBlockFreq(I);
Statistic &NumBranches = (I->succ_size() > 1) ? NumCondBranches
: NumUncondBranches;
Statistic &BranchTakenFreq = (I->succ_size() > 1) ? CondBranchTakenFreq
: UncondBranchTakenFreq;
Statistic &NumBranches =
(I->succ_size() > 1) ? NumCondBranches : NumUncondBranches;
Statistic &BranchTakenFreq =
(I->succ_size() > 1) ? CondBranchTakenFreq : UncondBranchTakenFreq;
for (MachineBasicBlock::succ_iterator SI = I->succ_begin(),
SE = I->succ_end();
SI != SE; ++SI) {