LLVM: lib/CodeGen/MachineBlockPlacement.cpp File Reference (original) (raw)
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| Namespaces | |
|---|---|
| namespace | llvm |
| This is an optimization pass for GlobalISel generic memory operations. | |
| Functions | |
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| STATISTIC (NumCondBranches, "Number of conditional branches") | |
| STATISTIC (NumUncondBranches, "Number of unconditional branches") | |
| STATISTIC (CondBranchTakenFreq, "Potential frequency of taking conditional branches") | |
| STATISTIC (UncondBranchTakenFreq, "Potential frequency of taking unconditional branches") | |
| INITIALIZE_PASS_BEGIN (MachineBlockPlacement, DEBUG_TYPE, "Branch Probability Basic Block Placement", false, false) INITIALIZE_PASS_END(MachineBlockPlacement | |
| Branch Probability Basic Block static false std::string | getBlockName (const MachineBasicBlock *BB) |
| Helper to print the name of a MBB. | |
| static BranchProbability | getAdjustedProbability (BranchProbability OrigProb, BranchProbability AdjustedSumProb) |
| The helper function returns the branch probability that is adjusted or normalized over the new total AdjustedSumProb. | |
| static bool | hasSameSuccessors (MachineBasicBlock &BB, SmallPtrSetImpl< const MachineBasicBlock * > &Successors) |
| Check if BB has exactly the successors in Successors. | |
| static bool | greaterWithBias (BlockFrequency A, BlockFrequency B, BlockFrequency EntryFreq) |
| Compare 2 BlockFrequency's with a small penalty for A. | |
| static BranchProbability | getLayoutSuccessorProbThreshold (const MachineBasicBlock *BB) |
| static uint64_t | countMBBInstruction (MachineBasicBlock *MBB) |
| INITIALIZE_PASS_BEGIN (MachineBlockPlacementStats, "block-placement-stats", "Basic Block Placement Stats", false, false) INITIALIZE_PASS_END(MachineBlockPlacementStats | |
| Variables | |
|---|---|
| static cl::opt< unsigned > | AlignAllBlock ("align-all-blocks", cl::desc("Force the alignment of all blocks in the function in log2 format " "(e.g 4 means align on 16B boundaries)."), cl::init(0), cl::Hidden) |
| static cl::opt< unsigned > | AlignAllNonFallThruBlocks ("align-all-nofallthru-blocks", cl::desc("Force the alignment of all blocks that have no fall-through " "predecessors (i.e. don't add nops that are executed). In log2 " "format (e.g 4 means align on 16B boundaries)."), cl::init(0), cl::Hidden) |
| static cl::opt< unsigned > | MaxBytesForAlignmentOverride ("max-bytes-for-alignment", cl::desc("Forces the maximum bytes allowed to be emitted when padding for " "alignment"), 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< unsigned > | LoopToColdBlockRatio ("loop-to-cold-block-ratio", cl::desc("Outline loop blocks from loop chain if (frequency of loop) / " "(frequency of block) is greater than this ratio"), cl::init(5), cl::Hidden) |
| static cl::opt< bool > | ForceLoopColdBlock ("force-loop-cold-block", cl::desc("Force outlining cold blocks from loops."), cl::init(false), cl::Hidden) |
| static cl::opt< bool > | PreciseRotationCost ("precise-rotation-cost", cl::desc("Model the cost of loop rotation more " "precisely by using profile data."), cl::init(false), cl::Hidden) |
| static cl::opt< bool > | ForcePreciseRotationCost ("force-precise-rotation-cost", cl::desc("Force the use of precise cost " "loop rotation strategy."), cl::init(false), cl::Hidden) |
| static cl::opt< unsigned > | MisfetchCost ("misfetch-cost", cl::desc("Cost that models the probabilistic risk of an instruction " "misfetch due to a jump comparing to falling through, whose cost " "is zero."), cl::init(1), cl::Hidden) |
| static cl::opt< unsigned > | JumpInstCost ("jump-inst-cost", cl::desc("Cost of jump instructions."), cl::init(1), cl::Hidden) |
| static cl::opt< bool > | TailDupPlacement ("tail-dup-placement", cl::desc("Perform tail duplication during placement. " "Creates more fallthrough opportunities in " "outline branches."), cl::init(true), cl::Hidden) |
| static cl::opt< bool > | BranchFoldPlacement ("branch-fold-placement", cl::desc("Perform branch folding during placement. " "Reduces code size."), cl::init(true), cl::Hidden) |
| static cl::opt< unsigned > | TailDupPlacementThreshold ("tail-dup-placement-threshold", cl::desc("Instruction cutoff for tail duplication during layout. " "Tail merging during layout is forced to have a threshold " "that won't conflict."), cl::init(2), cl::Hidden) |
| static cl::opt< unsigned > | TailDupPlacementAggressiveThreshold ("tail-dup-placement-aggressive-threshold", cl::desc("Instruction cutoff for aggressive tail duplication during " "layout. Used at -O3. Tail merging during layout is forced to " "have a threshold that won't conflict."), cl::init(4), cl::Hidden) |
| static cl::opt< unsigned > | TailDupPlacementPenalty ("tail-dup-placement-penalty", cl::desc("Cost penalty for blocks that can avoid breaking CFG by copying. " "Copying can increase fallthrough, but it also increases icache " "pressure. This parameter controls the penalty to account for that. " "Percent as integer."), cl::init(2), cl::Hidden) |
| static cl::opt< unsigned > | TailDupProfilePercentThreshold ("tail-dup-profile-percent-threshold", cl::desc("If profile count information is used in tail duplication cost " "model, the gained fall through number from tail duplication " "should be at least this percent of hot count."), cl::init(50), cl::Hidden) |
| static cl::opt< unsigned > | TriangleChainCount ("triangle-chain-count", cl::desc("Number of triangle-shaped-CFG's that need to be in a row for the " "triangle tail duplication heuristic to kick in. 0 to disable."), cl::init(2), cl::Hidden) |
| static cl::opt< bool > | RenumberBlocksBeforeView ("renumber-blocks-before-view", cl::desc("If true, basic blocks are re-numbered before MBP layout is printed " "into a dot graph. Only used when a function is being printed."), cl::init(false), cl::Hidden) |
| static cl::opt< unsigned > | ExtTspBlockPlacementMaxBlocks ("ext-tsp-block-placement-max-blocks", cl::desc("Maximum number of basic blocks in a function to run ext-TSP " "block placement."), cl::init(UINT_MAX), cl::Hidden) |
| static cl::opt< bool > | ApplyExtTspForSize ("apply-ext-tsp-for-size", cl::init(false), cl::Hidden, cl::desc("Use ext-tsp for size-aware block placement.")) |
| cl::opt< bool > | llvm::EnableExtTspBlockPlacement |
| cl::opt< bool > | llvm::ApplyExtTspWithoutProfile |
| cl::opt< unsigned > | llvm::StaticLikelyProb |
| cl::opt< unsigned > | llvm::ProfileLikelyProb |
| DEBUG_TYPE | |
| Branch Probability Basic Block | Placement |
| Branch Probability Basic Block | false |
| block placement | stats |
| block placement Basic Block Placement | Stats |
◆ DEBUG_TYPE
#define DEBUG_TYPE "block-placement"
◆ countMBBInstruction()
◆ getAdjustedProbability()
◆ getBlockName()
◆ getLayoutSuccessorProbThreshold()
◆ greaterWithBias()
Compare 2 BlockFrequency's with a small penalty for A.
In order to be conservative, we apply a X% penalty to account for increased icache pressure and static heuristics. For small frequencies we use only the numerators to improve accuracy. For simplicity, we assume the penalty is less than 100% TODO(iteratee): Use 64-bit fixed point edge frequencies everywhere.
Definition at line 817 of file MachineBlockPlacement.cpp.
References A, B, and TailDupPlacementPenalty.
◆ hasSameSuccessors()
◆ INITIALIZE_PASS_BEGIN() [1/2]
| INITIALIZE_PASS_BEGIN | ( | MachineBlockPlacement | , |
|---|---|---|---|
| DEBUG_TYPE | , | ||
| "Branch Probability Basic Block Placement" | , | ||
| false | , | ||
| false | |||
| ) |
◆ INITIALIZE_PASS_BEGIN() [2/2]
| INITIALIZE_PASS_BEGIN | ( | MachineBlockPlacementStats | , |
|---|---|---|---|
| "block-placement-stats" | , | ||
| "Basic Block Placement Stats" | , | ||
| false | , | ||
| false | |||
| ) |
◆ STATISTIC() [1/4]
| STATISTIC | ( | CondBranchTakenFreq | , |
|---|---|---|---|
| "Potential frequency of taking conditional branches" | |||
| ) |
◆ STATISTIC() [2/4]
| STATISTIC | ( | NumCondBranches | , |
|---|---|---|---|
| "Number of conditional branches" | |||
| ) |
◆ STATISTIC() [3/4]
| STATISTIC | ( | NumUncondBranches | , |
|---|---|---|---|
| "Number of unconditional branches" | |||
| ) |
◆ STATISTIC() [4/4]
| STATISTIC | ( | UncondBranchTakenFreq | , |
|---|---|---|---|
| "Potential frequency of taking unconditional branches" | |||
| ) |
◆ AlignAllBlock
| cl::opt< unsigned > AlignAllBlock("align-all-blocks", cl::desc("Force the alignment of all blocks in the function in log2 format " "(e.g 4 means align on 16B boundaries)."), cl::init(0), cl::Hidden) ( "align-all-blocks" , cl::desc("Force the alignment of all blocks in the function in log2 format " "(e.g 4 means align on 16B boundaries).") , cl::init(0) , cl::Hidden ) | static |
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◆ AlignAllNonFallThruBlocks
| cl::opt< unsigned > AlignAllNonFallThruBlocks("align-all-nofallthru-blocks", cl::desc("Force the alignment of all blocks that have no fall-through " "predecessors (i.e. don't add nops that are executed). In log2 " "format (e.g 4 means align on 16B boundaries)."), cl::init(0), cl::Hidden) ( "align-all-nofallthru-blocks" , cl::desc("Force the alignment of all blocks that have no fall-through " "predecessors (i.e. don't add nops that are executed). In log2 " "format (e.g 4 means align on 16B boundaries).") , cl::init(0) , cl::Hidden ) | static |
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◆ ApplyExtTspForSize
| cl::opt< bool > ApplyExtTspForSize("apply-ext-tsp-for-size", cl::init(false), cl::Hidden, cl::desc("Use ext-tsp for size-aware block placement.")) ( "apply-ext-tsp-for-size" , cl::init(false) , cl::Hidden , cl::desc("Use ext-tsp for size-aware block placement.") ) | static |
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◆ BranchFoldPlacement
| cl::opt< bool > BranchFoldPlacement("branch-fold-placement", cl::desc("Perform branch folding during placement. " "Reduces code size."), cl::init(true), cl::Hidden) ( "branch-fold-placement" , cl::desc("Perform branch folding during placement. " "Reduces code size.") , cl::init(true) , cl::Hidden ) | static |
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◆ DEBUG_TYPE
◆ ExitBlockBias
| 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) ( "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 |
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◆ ExtTspBlockPlacementMaxBlocks
◆ false
◆ ForceLoopColdBlock
| cl::opt< bool > ForceLoopColdBlock("force-loop-cold-block", cl::desc("Force outlining cold blocks from loops."), cl::init(false), cl::Hidden) ( "force-loop-cold-block" , cl::desc("Force outlining cold blocks from loops.") , cl::init(false) , cl::Hidden ) | static |
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◆ ForcePreciseRotationCost
| cl::opt< bool > ForcePreciseRotationCost("force-precise-rotation-cost", cl::desc("Force the use of precise cost " "loop rotation strategy."), cl::init(false), cl::Hidden) ( "force-precise-rotation-cost" , cl::desc("Force the use of precise cost " "loop rotation strategy.") , cl::init(false) , cl::Hidden ) | static |
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◆ JumpInstCost
| cl::opt< unsigned > JumpInstCost("jump-inst-cost", cl::desc("Cost of jump instructions."), cl::init(1), cl::Hidden) ( "jump-inst-cost" , cl::desc("Cost of jump instructions.") , cl::init(1) , cl::Hidden ) | static |
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◆ LoopToColdBlockRatio
| cl::opt< unsigned > LoopToColdBlockRatio("loop-to-cold-block-ratio", cl::desc("Outline loop blocks from loop chain if (frequency of loop) / " "(frequency of block) is greater than this ratio"), cl::init(5), cl::Hidden) ( "loop-to-cold-block-ratio" , cl::desc("Outline loop blocks from loop chain if (frequency of loop) / " "(frequency of block) is greater than this ratio") , cl::init(5) , cl::Hidden ) | static |
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◆ MaxBytesForAlignmentOverride
| cl::opt< unsigned > MaxBytesForAlignmentOverride("max-bytes-for-alignment", cl::desc("Forces the maximum bytes allowed to be emitted when padding for " "alignment"), cl::init(0), cl::Hidden) ( "max-bytes-for-alignment" , cl::desc("Forces the maximum bytes allowed to be emitted when padding for " "alignment") , cl::init(0) , cl::Hidden ) | static |
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◆ MisfetchCost
| cl::opt< unsigned > MisfetchCost("misfetch-cost", cl::desc("Cost that models the probabilistic risk of an instruction " "misfetch due to a jump comparing to falling through, whose cost " "is zero."), cl::init(1), cl::Hidden) ( "misfetch-cost" , cl::desc("Cost that models the probabilistic risk of an instruction " "misfetch due to a jump comparing to falling through, whose cost " "is zero.") , cl::init(1) , cl::Hidden ) | static |
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◆ Placement
Branch Probability Basic Block Placement
◆ PreciseRotationCost
| cl::opt< bool > PreciseRotationCost("precise-rotation-cost", cl::desc("Model the cost of loop rotation more " "precisely by using profile data."), cl::init(false), cl::Hidden) ( "precise-rotation-cost" , cl::desc("Model the cost of loop rotation more " "precisely by using profile data.") , cl::init(false) , cl::Hidden ) | static |
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◆ RenumberBlocksBeforeView
| cl::opt< bool > RenumberBlocksBeforeView("renumber-blocks-before-view", cl::desc( "If true, basic blocks are re-numbered before MBP layout is printed " "into a dot graph. Only used when a function is being printed."), cl::init(false), cl::Hidden) ( "renumber-blocks-before-view" , cl::desc( "If true, basic blocks are re-numbered before MBP layout is printed " "into a dot graph. Only used when a function is being printed.") , cl::init(false) , cl::Hidden ) | static |
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◆ stats
◆ Stats
Definition at line 3814 of file MachineBlockPlacement.cpp.
Referenced by llvm::ComputeCrossModuleImport(), llvm::pdb::PDBSymbol::dumpChildStats(), dumpImportListForModule(), dumpIR(), llvm::exportDebugifyStats(), llvm::pdb::PDBSymbol::getChildStats(), operator<<(), llvm::pdb::operator<<(), llvm::PrintStatistics(), llvm::PrintStatisticsJSON(), and llvm::BitcodeAnalyzer::printStats().
◆ TailDupPlacement
| cl::opt< bool > TailDupPlacement("tail-dup-placement", cl::desc("Perform tail duplication during placement. " "Creates more fallthrough opportunities in " "outline branches."), cl::init(true), cl::Hidden) ( "tail-dup-placement" , cl::desc("Perform tail duplication during placement. " "Creates more fallthrough opportunities in " "outline branches.") , cl::init(true) , cl::Hidden ) | static |
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◆ TailDupPlacementAggressiveThreshold
| cl::opt< unsigned > TailDupPlacementAggressiveThreshold("tail-dup-placement-aggressive-threshold", cl::desc("Instruction cutoff for aggressive tail duplication during " "layout. Used at -O3. Tail merging during layout is forced to " "have a threshold that won't conflict."), cl::init(4), cl::Hidden) ( "tail-dup-placement-aggressive-threshold" , cl::desc("Instruction cutoff for aggressive tail duplication during " "layout. Used at -O3. Tail merging during layout is forced to " "have a threshold that won't conflict.") , cl::init(4) , cl::Hidden ) | static |
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◆ TailDupPlacementPenalty
| cl::opt< unsigned > TailDupPlacementPenalty("tail-dup-placement-penalty", cl::desc( "Cost penalty for blocks that can avoid breaking CFG by copying. " "Copying can increase fallthrough, but it also increases icache " "pressure. This parameter controls the penalty to account for that. " "Percent as integer."), cl::init(2), cl::Hidden) ( "tail-dup-placement-penalty" , cl::desc( "Cost penalty for blocks that can avoid breaking CFG by copying. " "Copying can increase fallthrough, but it also increases icache " "pressure. This parameter controls the penalty to account for that. " "Percent as integer.") , cl::init(2) , cl::Hidden ) | static |
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◆ TailDupPlacementThreshold
| cl::opt< unsigned > TailDupPlacementThreshold("tail-dup-placement-threshold", cl::desc("Instruction cutoff for tail duplication during layout. " "Tail merging during layout is forced to have a threshold " "that won't conflict."), cl::init(2), cl::Hidden) ( "tail-dup-placement-threshold" , cl::desc("Instruction cutoff for tail duplication during layout. " "Tail merging during layout is forced to have a threshold " "that won't conflict.") , cl::init(2) , cl::Hidden ) | static |
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◆ TailDupProfilePercentThreshold
| cl::opt< unsigned > TailDupProfilePercentThreshold("tail-dup-profile-percent-threshold", cl::desc("If profile count information is used in tail duplication cost " "model, the gained fall through number from tail duplication " "should be at least this percent of hot count."), cl::init(50), cl::Hidden) ( "tail-dup-profile-percent-threshold" , cl::desc("If profile count information is used in tail duplication cost " "model, the gained fall through number from tail duplication " "should be at least this percent of hot count.") , cl::init(50) , cl::Hidden ) | static |
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◆ TriangleChainCount
| cl::opt< unsigned > TriangleChainCount("triangle-chain-count", cl::desc("Number of triangle-shaped-CFG's that need to be in a row for the " "triangle tail duplication heuristic to kick in. 0 to disable."), cl::init(2), cl::Hidden) ( "triangle-chain-count" , cl::desc("Number of triangle-shaped-CFG's that need to be in a row for the " "triangle tail duplication heuristic to kick in. 0 to disable.") , cl::init(2) , cl::Hidden ) | static |
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