[PM] General doxygen and comment cleanup for this pass.
llvm-svn: 227001
This commit is contained in:
Chandler Carruth
parent
7253bba458
commit
9dea5cdb8e
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@ -49,8 +49,7 @@ static unsigned getHash(const void *V) {
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//===----------------------------------------------------------------------===//
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namespace {
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/// SimpleValue - Instances of this struct represent available values in the
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/// scoped hash table.
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/// \brief Struct representing the available values in the scoped hash table.
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struct SimpleValue {
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Instruction *Inst;
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@ -196,8 +195,8 @@ bool DenseMapInfo<SimpleValue>::isEqual(SimpleValue LHS, SimpleValue RHS) {
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//===----------------------------------------------------------------------===//
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namespace {
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/// CallValue - Instances of this struct represent available call values in
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/// the scoped hash table.
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/// \brief Struct representing the available call values in the scoped hash
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/// table.
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struct CallValue {
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Instruction *Inst;
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@ -263,12 +262,13 @@ bool DenseMapInfo<CallValue>::isEqual(CallValue LHS, CallValue RHS) {
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namespace {
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/// EarlyCSE - This pass does a simple depth-first walk over the dominator
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/// tree, eliminating trivially redundant instructions and using instsimplify
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/// to canonicalize things as it goes. It is intended to be fast and catch
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/// obvious cases so that instcombine and other passes are more effective. It
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/// is expected that a later pass of GVN will catch the interesting/hard
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/// cases.
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/// \brief A simple and fast domtree-based CSE pass.
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///
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/// This pass does a simple depth-first walk over the dominator tree,
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/// eliminating trivially redundant instructions and using instsimplify to
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/// canonicalize things as it goes. It is intended to be fast and catch obvious
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/// cases so that instcombine and other passes are more effective. It is
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/// expected that a later pass of GVN will catch the interesting/hard cases.
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class EarlyCSE : public FunctionPass {
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public:
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const DataLayout *DL;
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@ -280,20 +280,22 @@ public:
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typedef ScopedHashTable<SimpleValue, Value *, DenseMapInfo<SimpleValue>,
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AllocatorTy> ScopedHTType;
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/// AvailableValues - This scoped hash table contains the current values of
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/// all of our simple scalar expressions. As we walk down the domtree, we
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/// look to see if instructions are in this: if so, we replace them with what
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/// we find, otherwise we insert them so that dominated values can succeed in
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/// their lookup.
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/// \brief A scoped hash table of the current values of all of our simple
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/// scalar expressions.
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///
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/// As we walk down the domtree, we look to see if instructions are in this:
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/// if so, we replace them with what we find, otherwise we insert them so
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/// that dominated values can succeed in their lookup.
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ScopedHTType *AvailableValues;
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/// AvailableLoads - This scoped hash table contains the current values
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/// of loads. This allows us to get efficient access to dominating loads when
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/// we have a fully redundant load. In addition to the most recent load, we
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/// keep track of a generation count of the read, which is compared against
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/// the current generation count. The current generation count is
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/// incremented after every possibly writing memory operation, which ensures
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/// that we only CSE loads with other loads that have no intervening store.
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/// \brief A scoped hash table of the current values of loads.
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///
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/// This allows us to get efficient access to dominating loads when we have
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/// a fully redundant load. In addition to the most recent load, we keep
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/// track of a generation count of the read, which is compared against the
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/// current generation count. The current generation count is incremented
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/// after every possibly writing memory operation, which ensures that we only
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/// CSE loads with other loads that have no intervening store.
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typedef RecyclingAllocator<
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BumpPtrAllocator,
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ScopedHashTableVal<Value *, std::pair<Value *, unsigned>>>
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@ -302,12 +304,14 @@ public:
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DenseMapInfo<Value *>, LoadMapAllocator> LoadHTType;
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LoadHTType *AvailableLoads;
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/// AvailableCalls - This scoped hash table contains the current values
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/// of read-only call values. It uses the same generation count as loads.
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/// \brief A scoped hash table of the current values of read-only call
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/// values.
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///
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/// It uses the same generation count as loads.
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typedef ScopedHashTable<CallValue, std::pair<Value *, unsigned>> CallHTType;
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CallHTType *AvailableCalls;
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/// CurrentGeneration - This is the current generation of the memory value.
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/// \brief This is the current generation of the memory value.
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unsigned CurrentGeneration;
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static char ID;
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@ -318,9 +322,9 @@ public:
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bool runOnFunction(Function &F) override;
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private:
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// NodeScope - almost a POD, but needs to call the constructors for the
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// scoped hash tables so that a new scope gets pushed on. These are RAII so
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// that the scope gets popped when the NodeScope is destroyed.
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// Almost a POD, but needs to call the constructors for the scoped hash
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// tables so that a new scope gets pushed on. These are RAII so that the
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// scope gets popped when the NodeScope is destroyed.
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class NodeScope {
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public:
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NodeScope(ScopedHTType *availableValues, LoadHTType *availableLoads,
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@ -337,10 +341,10 @@ private:
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CallHTType::ScopeTy CallScope;
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};
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// StackNode - contains all the needed information to create a stack for
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// doing a depth first tranversal of the tree. This includes scopes for
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// values, loads, and calls as well as the generation. There is a child
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// iterator so that the children do not need to be store spearately.
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// Contains all the needed information to create a stack for doing a depth
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// first tranversal of the tree. This includes scopes for values, loads, and
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// calls as well as the generation. There is a child iterator so that the
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// children do not need to be store spearately.
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class StackNode {
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public:
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StackNode(ScopedHTType *availableValues, LoadHTType *availableLoads,
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@ -381,7 +385,6 @@ private:
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bool processNode(DomTreeNode *Node);
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// This transformation requires dominator postdominator info
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addRequired<AssumptionCacheTracker>();
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AU.addRequired<DominatorTreeWrapperPass>();
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@ -393,7 +396,6 @@ private:
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char EarlyCSE::ID = 0;
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// createEarlyCSEPass - The public interface to this file.
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FunctionPass *llvm::createEarlyCSEPass() { return new EarlyCSE(); }
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INITIALIZE_PASS_BEGIN(EarlyCSE, "early-cse", "Early CSE", false, false)
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