|
LLVM
4.0.0
|
#include "llvm/Transforms/Scalar/JumpThreading.h"#include "llvm/Transforms/Scalar.h"#include "llvm/ADT/DenseMap.h"#include "llvm/ADT/DenseSet.h"#include "llvm/ADT/STLExtras.h"#include "llvm/ADT/Statistic.h"#include "llvm/Analysis/GlobalsModRef.h"#include "llvm/Analysis/CFG.h"#include "llvm/Analysis/BlockFrequencyInfoImpl.h"#include "llvm/Analysis/ConstantFolding.h"#include "llvm/Analysis/InstructionSimplify.h"#include "llvm/Analysis/Loads.h"#include "llvm/Analysis/LoopInfo.h"#include "llvm/Analysis/ValueTracking.h"#include "llvm/IR/DataLayout.h"#include "llvm/IR/IntrinsicInst.h"#include "llvm/IR/LLVMContext.h"#include "llvm/IR/MDBuilder.h"#include "llvm/IR/Metadata.h"#include "llvm/Pass.h"#include "llvm/Support/CommandLine.h"#include "llvm/Support/Debug.h"#include "llvm/Support/raw_ostream.h"#include "llvm/Transforms/Utils/BasicBlockUtils.h"#include "llvm/Transforms/Utils/Local.h"#include "llvm/Transforms/Utils/SSAUpdater.h"#include <algorithm>#include <memory>Go to the source code of this file.
Macros | |
| #define | DEBUG_TYPE "jump-threading" |
Functions | |
| STATISTIC (NumThreads,"Number of jumps threaded") | |
| STATISTIC (NumFolds,"Number of terminators folded") | |
| STATISTIC (NumDupes,"Number of branch blocks duplicated to eliminate phi") | |
| INITIALIZE_PASS_BEGIN (JumpThreading,"jump-threading","Jump Threading", false, false) INITIALIZE_PASS_END(JumpThreading | |
| static unsigned | getJumpThreadDuplicationCost (const BasicBlock *BB, unsigned Threshold) |
| getJumpThreadDuplicationCost - Return the cost of duplicating this block to thread across it. More... | |
| static Constant * | getKnownConstant (Value *Val, ConstantPreference Preference) |
| getKnownConstant - Helper method to determine if we can thread over a terminator with the given value as its condition, and if so what value to use for that. More... | |
| static unsigned | GetBestDestForJumpOnUndef (BasicBlock *BB) |
| GetBestDestForBranchOnUndef - If we determine that the specified block ends in an undefined jump, decide which block is best to revector to. More... | |
| static bool | hasAddressTakenAndUsed (BasicBlock *BB) |
| static BasicBlock * | FindMostPopularDest (BasicBlock *BB, const SmallVectorImpl< std::pair< BasicBlock *, BasicBlock * > > &PredToDestList) |
| FindMostPopularDest - The specified list contains multiple possible threadable destinations. More... | |
| static void | AddPHINodeEntriesForMappedBlock (BasicBlock *PHIBB, BasicBlock *OldPred, BasicBlock *NewPred, DenseMap< Instruction *, Value * > &ValueMap) |
| AddPHINodeEntriesForMappedBlock - We're adding 'NewPred' as a new predecessor to the PHIBB block. More... | |
Variables | |
| static cl::opt< unsigned > | BBDuplicateThreshold ("jump-threading-threshold", cl::desc("Max block size to duplicate for jump threading"), cl::init(6), cl::Hidden) |
| static cl::opt< unsigned > | ImplicationSearchThreshold ("jump-threading-implication-search-threshold", cl::desc("The number of predecessors to search for a stronger ""condition to use to thread over a weaker condition"), cl::init(3), cl::Hidden) |
| jump | threading |
| jump Jump | Threading |
| jump Jump | false |
| #define DEBUG_TYPE "jump-threading" |
Definition at line 45 of file JumpThreading.cpp.
|
static |
AddPHINodeEntriesForMappedBlock - We're adding 'NewPred' as a new predecessor to the PHIBB block.
If it has PHI nodes, add entries for NewPred using the entries from OldPred (suitably mapped).
Definition at line 1428 of file JumpThreading.cpp.
References llvm::PHINode::addIncoming(), llvm::BasicBlock::begin(), llvm::dyn_cast(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::find(), llvm::PHINode::getIncomingValueForBlock(), and I.
Referenced by llvm::JumpThreadingPass::DuplicateCondBranchOnPHIIntoPred(), and llvm::JumpThreadingPass::ThreadEdge().
|
static |
FindMostPopularDest - The specified list contains multiple possible threadable destinations.
Pick the one that occurs the most frequently in the list.
Definition at line 1124 of file JumpThreading.cpp.
References assert(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::begin(), llvm::SmallVectorImpl< T >::clear(), llvm::SmallVectorBase::empty(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::TerminatorInst::getNumSuccessors(), llvm::TerminatorInst::getSuccessor(), llvm::BasicBlock::getTerminator(), i, llvm::is_contained(), and llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back().
Referenced by llvm::JumpThreadingPass::ProcessThreadableEdges().
|
static |
GetBestDestForBranchOnUndef - If we determine that the specified block ends in an undefined jump, decide which block is best to revector to.
Since we can pick an arbitrary destination, we pick the successor with the fewest predecessors. This should reduce the in-degree of the others.
Definition at line 673 of file JumpThreading.cpp.
References llvm::TerminatorInst::getNumSuccessors(), llvm::TerminatorInst::getSuccessor(), llvm::BasicBlock::getTerminator(), i, llvm::pred_begin(), and llvm::pred_end().
Referenced by llvm::JumpThreadingPass::ProcessBlock(), and llvm::JumpThreadingPass::ProcessThreadableEdges().
|
static |
getJumpThreadDuplicationCost - Return the cost of duplicating this block to thread across it.
Stop scanning the block when passing the threshold.
Ignore PHI nodes, these will be flattened when duplication happens.
Definition at line 260 of file JumpThreading.cpp.
References llvm::BasicBlock::getFirstNonPHI(), llvm::BasicBlock::getTerminator(), and I.
Referenced by llvm::JumpThreadingPass::DuplicateCondBranchOnPHIIntoPred(), and llvm::JumpThreadingPass::ThreadEdge().
|
static |
getKnownConstant - Helper method to determine if we can thread over a terminator with the given value as its condition, and if so what value to use for that.
What kind of value this is depends on whether we want an integer or a block address, but an undef is always accepted. Returns null if Val is null or not an appropriate constant.
Definition at line 354 of file JumpThreading.cpp.
References llvm::dyn_cast(), llvm::Value::stripPointerCasts(), and llvm::jumpthreading::WantBlockAddress.
Referenced by llvm::JumpThreadingPass::ComputeValueKnownInPredecessors(), and llvm::JumpThreadingPass::ProcessBlock().
|
static |
Definition at line 691 of file JumpThreading.cpp.
References llvm::BlockAddress::get(), llvm::BasicBlock::hasAddressTaken(), llvm::Constant::removeDeadConstantUsers(), and llvm::Value::use_empty().
Referenced by llvm::JumpThreadingPass::ProcessBlock().
| STATISTIC | ( | NumThreads | , |
| "Number of jumps threaded" | |||
| ) |
| STATISTIC | ( | NumFolds | , |
| "Number of terminators folded" | |||
| ) |
| STATISTIC | ( | NumDupes | , |
| "Number of branch blocks duplicated to eliminate phi" | |||
| ) |
|
static |
Referenced by llvm::JumpThreadingPass::JumpThreadingPass().
| jump Jump false |
Definition at line 107 of file JumpThreading.cpp.
|
static |
Referenced by llvm::JumpThreadingPass::ProcessImpliedCondition().
| jump threading |
Definition at line 107 of file JumpThreading.cpp.
| jump Jump Threading |
Definition at line 107 of file JumpThreading.cpp.
1.8.6