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Diffstat (limited to 'lib/Transforms/Scalar/PredicateSimplifier.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/PredicateSimplifier.cpp | 2704 |
1 files changed, 0 insertions, 2704 deletions
diff --git a/lib/Transforms/Scalar/PredicateSimplifier.cpp b/lib/Transforms/Scalar/PredicateSimplifier.cpp deleted file mode 100644 index b8ac1828db..0000000000 --- a/lib/Transforms/Scalar/PredicateSimplifier.cpp +++ /dev/null @@ -1,2704 +0,0 @@ -//===-- PredicateSimplifier.cpp - Path Sensitive Simplifier ---------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// Path-sensitive optimizer. In a branch where x == y, replace uses of -// x with y. Permits further optimization, such as the elimination of -// the unreachable call: -// -// void test(int *p, int *q) -// { -// if (p != q) -// return; -// -// if (*p != *q) -// foo(); // unreachable -// } -// -//===----------------------------------------------------------------------===// -// -// The InequalityGraph focusses on four properties; equals, not equals, -// less-than and less-than-or-equals-to. The greater-than forms are also held -// just to allow walking from a lesser node to a greater one. These properties -// are stored in a lattice; LE can become LT or EQ, NE can become LT or GT. -// -// These relationships define a graph between values of the same type. Each -// Value is stored in a map table that retrieves the associated Node. This -// is how EQ relationships are stored; the map contains pointers from equal -// Value to the same node. The node contains a most canonical Value* form -// and the list of known relationships with other nodes. -// -// If two nodes are known to be inequal, then they will contain pointers to -// each other with an "NE" relationship. If node getNode(%x) is less than -// getNode(%y), then the %x node will contain <%y, GT> and %y will contain -// <%x, LT>. This allows us to tie nodes together into a graph like this: -// -// %a < %b < %c < %d -// -// with four nodes representing the properties. The InequalityGraph provides -// querying with "isRelatedBy" and mutators "addEquality" and "addInequality". -// To find a relationship, we start with one of the nodes any binary search -// through its list to find where the relationships with the second node start. -// Then we iterate through those to find the first relationship that dominates -// our context node. -// -// To create these properties, we wait until a branch or switch instruction -// implies that a particular value is true (or false). The VRPSolver is -// responsible for analyzing the variable and seeing what new inferences -// can be made from each property. For example: -// -// %P = icmp ne i32* %ptr, null -// %a = and i1 %P, %Q -// br i1 %a label %cond_true, label %cond_false -// -// For the true branch, the VRPSolver will start with %a EQ true and look at -// the definition of %a and find that it can infer that %P and %Q are both -// true. From %P being true, it can infer that %ptr NE null. For the false -// branch it can't infer anything from the "and" instruction. -// -// Besides branches, we can also infer properties from instruction that may -// have undefined behaviour in certain cases. For example, the dividend of -// a division may never be zero. After the division instruction, we may assume -// that the dividend is not equal to zero. -// -//===----------------------------------------------------------------------===// -// -// The ValueRanges class stores the known integer bounds of a Value. When we -// encounter i8 %a u< %b, the ValueRanges stores that %a = [1, 255] and -// %b = [0, 254]. -// -// It never stores an empty range, because that means that the code is -// unreachable. It never stores a single-element range since that's an equality -// relationship and better stored in the InequalityGraph, nor an empty range -// since that is better stored in UnreachableBlocks. -// -//===----------------------------------------------------------------------===// - -#define DEBUG_TYPE "predsimplify" -#include "llvm/Transforms/Scalar.h" -#include "llvm/Constants.h" -#include "llvm/DerivedTypes.h" -#include "llvm/Instructions.h" -#include "llvm/Pass.h" -#include "llvm/ADT/DepthFirstIterator.h" -#include "llvm/ADT/SetOperations.h" -#include "llvm/ADT/SetVector.h" -#include "llvm/ADT/Statistic.h" -#include "llvm/ADT/STLExtras.h" -#include "llvm/Analysis/Dominators.h" -#include "llvm/Assembly/Writer.h" -#include "llvm/Support/CFG.h" -#include "llvm/Support/ConstantRange.h" -#include "llvm/Support/Debug.h" -#include "llvm/Support/InstVisitor.h" -#include "llvm/Support/raw_ostream.h" -#include "llvm/Target/TargetData.h" -#include "llvm/Transforms/Utils/Local.h" -#include <algorithm> -#include <deque> -#include <stack> -using namespace llvm; - -STATISTIC(NumVarsReplaced, "Number of argument substitutions"); -STATISTIC(NumInstruction , "Number of instructions removed"); -STATISTIC(NumSimple , "Number of simple replacements"); -STATISTIC(NumBlocks , "Number of blocks marked unreachable"); -STATISTIC(NumSnuggle , "Number of comparisons snuggled"); - -static const ConstantRange empty(1, false); - -namespace { - class DomTreeDFS { - public: - class Node { - friend class DomTreeDFS; - public: - typedef std::vector<Node *>::iterator iterator; - typedef std::vector<Node *>::const_iterator const_iterator; - - unsigned getDFSNumIn() const { return DFSin; } - unsigned getDFSNumOut() const { return DFSout; } - - BasicBlock *getBlock() const { return BB; } - - iterator begin() { return Children.begin(); } - iterator end() { return Children.end(); } - - const_iterator begin() const { return Children.begin(); } - const_iterator end() const { return Children.end(); } - - bool dominates(const Node *N) const { - return DFSin <= N->DFSin && DFSout >= N->DFSout; - } - - bool DominatedBy(const Node *N) const { - return N->dominates(this); - } - - /// Sorts by the number of descendants. With this, you can iterate - /// through a sorted list and the first matching entry is the most - /// specific match for your basic block. The order provided is stable; - /// DomTreeDFS::Nodes with the same number of descendants are sorted by - /// DFS in number. - bool operator<(const Node &N) const { - unsigned spread = DFSout - DFSin; - unsigned N_spread = N.DFSout - N.DFSin; - if (spread == N_spread) return DFSin < N.DFSin; - return spread < N_spread; - } - bool operator>(const Node &N) const { return N < *this; } - - private: - unsigned DFSin, DFSout; - BasicBlock *BB; - - std::vector<Node *> Children; - }; - - // XXX: this may be slow. Instead of using "new" for each node, consider - // putting them in a vector to keep them contiguous. - explicit DomTreeDFS(DominatorTree *DT) { - std::stack<std::pair<Node *, DomTreeNode *> > S; - - Entry = new Node; - Entry->BB = DT->getRootNode()->getBlock(); - S.push(std::make_pair(Entry, DT->getRootNode())); - - NodeMap[Entry->BB] = Entry; - - while (!S.empty()) { - std::pair<Node *, DomTreeNode *> &Pair = S.top(); - Node *N = Pair.first; - DomTreeNode *DTNode = Pair.second; - S.pop(); - - for (DomTreeNode::iterator I = DTNode->begin(), E = DTNode->end(); - I != E; ++I) { - Node *NewNode = new Node; - NewNode->BB = (*I)->getBlock(); - N->Children.push_back(NewNode); - S.push(std::make_pair(NewNode, *I)); - - NodeMap[NewNode->BB] = NewNode; - } - } - - renumber(); - -#ifndef NDEBUG - DEBUG(dump()); -#endif - } - -#ifndef NDEBUG - virtual -#endif - ~DomTreeDFS() { - std::stack<Node *> S; - - S.push(Entry); - while (!S.empty()) { - Node *N = S.top(); S.pop(); - - for (Node::iterator I = N->begin(), E = N->end(); I != E; ++I) - S.push(*I); - - delete N; - } - } - - /// getRootNode - This returns the entry node for the CFG of the function. - Node *getRootNode() const { return Entry; } - - /// getNodeForBlock - return the node for the specified basic block. - Node *getNodeForBlock(BasicBlock *BB) const { - if (!NodeMap.count(BB)) return 0; - return const_cast<DomTreeDFS*>(this)->NodeMap[BB]; - } - - /// dominates - returns true if the basic block for I1 dominates that of - /// the basic block for I2. If the instructions belong to the same basic - /// block, the instruction first instruction sequentially in the block is - /// considered dominating. - bool dominates(Instruction *I1, Instruction *I2) { - BasicBlock *BB1 = I1->getParent(), - *BB2 = I2->getParent(); - if (BB1 == BB2) { - if (isa<TerminatorInst>(I1)) return false; - if (isa<TerminatorInst>(I2)) return true; - if ( isa<PHINode>(I1) && !isa<PHINode>(I2)) return true; - if (!isa<PHINode>(I1) && isa<PHINode>(I2)) return false; - - for (BasicBlock::const_iterator I = BB2->begin(), E = BB2->end(); - I != E; ++I) { - if (&*I == I1) return true; - else if (&*I == I2) return false; - } - assert(!"Instructions not found in parent BasicBlock?"); - } else { - Node *Node1 = getNodeForBlock(BB1), - *Node2 = getNodeForBlock(BB2); - return Node1 && Node2 && Node1->dominates(Node2); - } - return false; // Not reached - } - - private: - /// renumber - calculates the depth first search numberings and applies - /// them onto the nodes. - void renumber() { - std::stack<std::pair<Node *, Node::iterator> > S; - unsigned n = 0; - - Entry->DFSin = ++n; - S.push(std::make_pair(Entry, Entry->begin())); - - while (!S.empty()) { - std::pair<Node *, Node::iterator> &Pair = S.top(); - Node *N = Pair.first; - Node::iterator &I = Pair.second; - - if (I == N->end()) { - N->DFSout = ++n; - S.pop(); - } else { - Node *Next = *I++; - Next->DFSin = ++n; - S.push(std::make_pair(Next, Next->begin())); - } - } - } - -#ifndef NDEBUG - virtual void dump() const { - dump(errs()); - } - - void dump(raw_ostream &os) const { - os << "Predicate simplifier DomTreeDFS: \n"; - dump(Entry, 0, os); - os << "\n\n"; - } - - void dump(Node *N, int depth, raw_ostream &os) const { - ++depth; - for (int i = 0; i < depth; ++i) { os << " "; } - os << "[" << depth << "] "; - - os << N->getBlock()->getNameStr() << " (" << N->getDFSNumIn() - << ", " << N->getDFSNumOut() << ")\n"; - - for (Node::iterator I = N->begin(), E = N->end(); I != E; ++I) - dump(*I, depth, os); - } -#endif - - Node *Entry; - std::map<BasicBlock *, Node *> NodeMap; - }; - - // SLT SGT ULT UGT EQ - // 0 1 0 1 0 -- GT 10 - // 0 1 0 1 1 -- GE 11 - // 0 1 1 0 0 -- SGTULT 12 - // 0 1 1 0 1 -- SGEULE 13 - // 0 1 1 1 0 -- SGT 14 - // 0 1 1 1 1 -- SGE 15 - // 1 0 0 1 0 -- SLTUGT 18 - // 1 0 0 1 1 -- SLEUGE 19 - // 1 0 1 0 0 -- LT 20 - // 1 0 1 0 1 -- LE 21 - // 1 0 1 1 0 -- SLT 22 - // 1 0 1 1 1 -- SLE 23 - // 1 1 0 1 0 -- UGT 26 - // 1 1 0 1 1 -- UGE 27 - // 1 1 1 0 0 -- ULT 28 - // 1 1 1 0 1 -- ULE 29 - // 1 1 1 1 0 -- NE 30 - enum LatticeBits { - EQ_BIT = 1, UGT_BIT = 2, ULT_BIT = 4, SGT_BIT = 8, SLT_BIT = 16 - }; - enum LatticeVal { - GT = SGT_BIT | UGT_BIT, - GE = GT | EQ_BIT, - LT = SLT_BIT | ULT_BIT, - LE = LT | EQ_BIT, - NE = SLT_BIT | SGT_BIT | ULT_BIT | UGT_BIT, - SGTULT = SGT_BIT | ULT_BIT, - SGEULE = SGTULT | EQ_BIT, - SLTUGT = SLT_BIT | UGT_BIT, - SLEUGE = SLTUGT | EQ_BIT, - ULT = SLT_BIT | SGT_BIT | ULT_BIT, - UGT = SLT_BIT | SGT_BIT | UGT_BIT, - SLT = SLT_BIT | ULT_BIT | UGT_BIT, - SGT = SGT_BIT | ULT_BIT | UGT_BIT, - SLE = SLT | EQ_BIT, - SGE = SGT | EQ_BIT, - ULE = ULT | EQ_BIT, - UGE = UGT | EQ_BIT - }; - -#ifndef NDEBUG - /// validPredicate - determines whether a given value is actually a lattice - /// value. Only used in assertions or debugging. - static bool validPredicate(LatticeVal LV) { - switch (LV) { - case GT: case GE: case LT: case LE: case NE: - case SGTULT: case SGT: case SGEULE: - case SLTUGT: case SLT: case SLEUGE: - case ULT: case UGT: - case SLE: case SGE: case ULE: case UGE: - return true; - default: - return false; - } - } -#endif - - /// reversePredicate - reverse the direction of the inequality - static LatticeVal reversePredicate(LatticeVal LV) { - unsigned reverse = LV ^ (SLT_BIT|SGT_BIT|ULT_BIT|UGT_BIT); //preserve EQ_BIT - - if ((reverse & (SLT_BIT|SGT_BIT)) == 0) - reverse |= (SLT_BIT|SGT_BIT); - - if ((reverse & (ULT_BIT|UGT_BIT)) == 0) - reverse |= (ULT_BIT|UGT_BIT); - - LatticeVal Rev = static_cast<LatticeVal>(reverse); - assert(validPredicate(Rev) && "Failed reversing predicate."); - return Rev; - } - - /// ValueNumbering stores the scope-specific value numbers for a given Value. - class ValueNumbering { - - /// VNPair is a tuple of {Value, index number, DomTreeDFS::Node}. It - /// includes the comparison operators necessary to allow you to store it - /// in a sorted vector. - class VNPair { - public: - Value *V; - unsigned index; - DomTreeDFS::Node *Subtree; - - VNPair(Value *V, unsigned index, DomTreeDFS::Node *Subtree) - : V(V), index(index), Subtree(Subtree) {} - - bool operator==(const VNPair &RHS) const { - return V == RHS.V && Subtree == RHS.Subtree; - } - - bool operator<(const VNPair &RHS) const { - if (V != RHS.V) return V < RHS.V; - return *Subtree < *RHS.Subtree; - } - - bool operator<(Value *RHS) const { - return V < RHS; - } - - bool operator>(Value *RHS) const { - return V > RHS; - } - - friend bool operator<(Value *RHS, const VNPair &pair) { - return pair.operator>(RHS); - } - }; - - typedef std::vector<VNPair> VNMapType; - VNMapType VNMap; - - /// The canonical choice for value number at index. - std::vector<Value *> Values; - - DomTreeDFS *DTDFS; - - public: -#ifndef NDEBUG - virtual ~ValueNumbering() {} - virtual void dump() { - print(errs()); - } - - void print(raw_ostream &os) { - for (unsigned i = 1; i <= Values.size(); ++i) { - os << i << " = "; - WriteAsOperand(os, Values[i-1]); - os << " {"; - for (unsigned j = 0; j < VNMap.size(); ++j) { - if (VNMap[j].index == i) { - WriteAsOperand(os, VNMap[j].V); - os << " (" << VNMap[j].Subtree->getDFSNumIn() << ") "; - } - } - os << "}\n"; - } - } -#endif - - /// compare - returns true if V1 is a better canonical value than V2. - bool compare(Value *V1, Value *V2) const { - if (isa<Constant>(V1)) - return !isa<Constant>(V2); - else if (isa<Constant>(V2)) - return false; - else if (isa<Argument>(V1)) - return !isa<Argument>(V2); - else if (isa<Argument>(V2)) - return false; - - Instruction *I1 = dyn_cast<Instruction>(V1); - Instruction *I2 = dyn_cast<Instruction>(V2); - - if (!I1 || !I2) - return V1->getNumUses() < V2->getNumUses(); - - return DTDFS->dominates(I1, I2); - } - - ValueNumbering(DomTreeDFS *DTDFS) : DTDFS(DTDFS) {} - - /// valueNumber - finds the value number for V under the Subtree. If - /// there is no value number, returns zero. - unsigned valueNumber(Value *V, DomTreeDFS::Node *Subtree) { - if (!(isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) || - V->getType() == Type::getVoidTy(V->getContext())) return 0; - - VNMapType::iterator E = VNMap.end(); - VNPair pair(V, 0, Subtree); - VNMapType::iterator I = std::lower_bound(VNMap.begin(), E, pair); - while (I != E && I->V == V) { - if (I->Subtree->dominates(Subtree)) - return I->index; - ++I; - } - return 0; - } - - /// getOrInsertVN - always returns a value number, creating it if necessary. - unsigned getOrInsertVN(Value *V, DomTreeDFS::Node *Subtree) { - if (unsigned n = valueNumber(V, Subtree)) - return n; - else - return newVN(V); - } - - /// newVN - creates a new value number. Value V must not already have a - /// value number assigned. - unsigned newVN(Value *V) { - assert((isa<Constant>(V) || isa<Argument>(V) || isa<Instruction>(V)) && - "Bad Value for value numbering."); - assert(V->getType() != Type::getVoidTy(V->getContext()) && - "Won't value number a void value"); - - Values.push_back(V); - - VNPair pair = VNPair(V, Values.size(), DTDFS->getRootNode()); - VNMapType::iterator I = std::lower_bound(VNMap.begin(), VNMap.end(), pair); - assert((I == VNMap.end() || value(I->index) != V) && - "Attempt to create a duplicate value number."); - VNMap.insert(I, pair); - - return Values.size(); - } - - /// value - returns the Value associated with a value number. - Value *value(unsigned index) const { - assert(index != 0 && "Zero index is reserved for not found."); - assert(index <= Values.size() && "Index out of range."); - return Values[index-1]; - } - - /// canonicalize - return a Value that is equal to V under Subtree. - Value *canonicalize(Value *V, DomTreeDFS::Node *Subtree) { - if (isa<Constant>(V)) return V; - - if (unsigned n = valueNumber(V, Subtree)) - return value(n); - else - return V; - } - - /// addEquality - adds that value V belongs to the set of equivalent - /// values defined by value number n under Subtree. - void addEquality(unsigned n, Value *V, DomTreeDFS::Node *Subtree) { - assert(canonicalize(value(n), Subtree) == value(n) && - "Node's 'canonical' choice isn't best within this subtree."); - - // Suppose that we are given "%x -> node #1 (%y)". The problem is that - // we may already have "%z -> node #2 (%x)" somewhere above us in the - // graph. We need to find those edges and add "%z -> node #1 (%y)" - // to keep the lookups canonical. - - std::vector<Value *> ToRepoint(1, V); - - if (unsigned Conflict = valueNumber(V, Subtree)) { - for (VNMapType::iterator I = VNMap.begin(), E = VNMap.end(); - I != E; ++I) { - if (I->index == Conflict && I->Subtree->dominates(Subtree)) - ToRepoint.push_back(I->V); - } - } - - for (std::vector<Value *>::iterator VI = ToRepoint.begin(), - VE = ToRepoint.end(); VI != VE; ++VI) { - Value *V = *VI; - - VNPair pair(V, n, Subtree); - VNMapType::iterator B = VNMap.begin(), E = VNMap.end(); - VNMapType::iterator I = std::lower_bound(B, E, pair); - if (I != E && I->V == V && I->Subtree == Subtree) - I->index = n; // Update best choice - else - VNMap.insert(I, pair); // New Value - - // XXX: we currently don't have to worry about updating values with - // more specific Subtrees, but we will need to for PHI node support. - -#ifndef NDEBUG - Value *V_n = value(n); - if (isa<Constant>(V) && isa<Constant>(V_n)) { - assert(V == V_n && "Constant equals different constant?"); - } -#endif - } - } - - /// remove - removes all references to value V. - void remove(Value *V) { - VNMapType::iterator B = VNMap.begin(), E = VNMap.end(); - VNPair pair(V, 0, DTDFS->getRootNode()); - VNMapType::iterator J = std::upper_bound(B, E, pair); - VNMapType::iterator I = J; - - while (I != B && (I == E || I->V == V)) --I; - - VNMap.erase(I, J); - } - }; - - /// The InequalityGraph stores the relationships between values. - /// Each Value in the graph is assigned to a Node. Nodes are pointer - /// comparable for equality. The caller is expected to maintain the logical - /// consistency of the system. - /// - /// The InequalityGraph class may invalidate Node*s after any mutator call. - /// @brief The InequalityGraph stores the relationships between values. - class InequalityGraph { - ValueNumbering &VN; - DomTreeDFS::Node *TreeRoot; - - InequalityGraph(); // DO NOT IMPLEMENT - InequalityGraph(InequalityGraph &); // DO NOT IMPLEMENT - public: - InequalityGraph(ValueNumbering &VN, DomTreeDFS::Node *TreeRoot) - : VN(VN), TreeRoot(TreeRoot) {} - - class Node; - - /// An Edge is contained inside a Node making one end of the edge implicit - /// and contains a pointer to the other end. The edge contains a lattice - /// value specifying the relationship and an DomTreeDFS::Node specifying - /// the root in the dominator tree to which this edge applies. - class Edge { - public: - Edge(unsigned T, LatticeVal V, DomTreeDFS::Node *ST) - : To(T), LV(V), Subtree(ST) {} - - unsigned To; - LatticeVal LV; - DomTreeDFS::Node *Subtree; - - bool operator<(const Edge &edge) const { - if (To != edge.To) return To < edge.To; - return *Subtree < *edge.Subtree; - } - - bool operator<(unsigned to) const { - return To < to; - } - - bool operator>(unsigned to) const { - return To > to; - } - - friend bool operator<(unsigned to, const Edge &edge) { - return edge.operator>(to); - } - }; - - /// A single node in the InequalityGraph. This stores the canonical Value - /// for the node, as well as the relationships with the neighbours. - /// - /// @brief A single node in the InequalityGraph. - class Node { - friend class InequalityGraph; - - typedef SmallVector<Edge, 4> RelationsType; - RelationsType Relations; - - // TODO: can this idea improve performance? - //friend class std::vector<Node>; - //Node(Node &N) { RelationsType.swap(N.RelationsType); } - - public: - typedef RelationsType::iterator iterator; - typedef RelationsType::const_iterator const_iterator; - -#ifndef NDEBUG - virtual ~Node() {} - virtual void dump() const { - dump(errs()); - } - private: - void dump(raw_ostream &os) const { - static const std::string names[32] = - { "000000", "000001", "000002", "000003", "000004", "000005", - "000006", "000007", "000008", "000009", " >", " >=", - " s>u<", "s>=u<=", " s>", " s>=", "000016", "000017", - " s<u>", "s<=u>=", " <", " <=", " s<", " s<=", - "000024", "000025", " u>", " u>=", " u<", " u<=", - " !=", "000031" }; - for (Node::const_iterator NI = begin(), NE = end(); NI != NE; ++NI) { - os << names[NI->LV] << " " << NI->To - << " (" << NI->Subtree->getDFSNumIn() << "), "; - } - } - public: -#endif - - iterator begin() { return Relations.begin(); } - iterator end() { return Relations.end(); } - const_iterator begin() const { return Relations.begin(); } - const_iterator end() const { return Relations.end(); } - - iterator find(unsigned n, DomTreeDFS::Node *Subtree) { - iterator E = end(); - for (iterator I = std::lower_bound(begin(), E, n); - I != E && I->To == n; ++I) { - if (Subtree->DominatedBy(I->Subtree)) - return I; - } - return E; - } - - const_iterator find(unsigned n, DomTreeDFS::Node *Subtree) const { - const_iterator E = end(); - for (const_iterator I = std::lower_bound(begin(), E, n); - I != E && I->To == n; ++I) { - if (Subtree->DominatedBy(I->Subtree)) - return I; - } - return E; - } - - /// update - updates the lattice value for a given node, creating a new - /// entry if one doesn't exist. The new lattice value must not be - /// inconsistent with any previously existing value. - void update(unsigned n, LatticeVal R, DomTreeDFS::Node *Subtree) { - assert(validPredicate(R) && "Invalid predicate."); - - Edge edge(n, R, Subtree); - iterator B = begin(), E = end(); - iterator I = std::lower_bound(B, E, edge); - - iterator J = I; - while (J != E && J->To == n) { - if (Subtree->DominatedBy(J->Subtree)) - break; - ++J; - } - - if (J != E && J->To == n) { - edge.LV = static_cast<LatticeVal>(J->LV & R); - assert(validPredicate(edge.LV) && "Invalid union of lattice values."); - - if (edge.LV == J->LV) - return; // This update adds nothing new. - } - - if (I != B) { - // We also have to tighten any edge beneath our update. - for (iterator K = I - 1; K->To == n; --K) { - if (K->Subtree->DominatedBy(Subtree)) { - LatticeVal LV = static_cast<LatticeVal>(K->LV & edge.LV); - assert(validPredicate(LV) && "Invalid union of lattice values"); - K->LV = LV; - } - if (K == B) break; - } - } - - // Insert new edge at Subtree if it isn't already there. - if (I == E || I->To != n || Subtree != I->Subtree) - Relations.insert(I, edge); - } - }; - - private: - - std::vector<Node> Nodes; - - public: - /// node - returns the node object at a given value number. The pointer - /// returned may be invalidated on the next call to node(). - Node *node(unsigned index) { - assert(VN.value(index)); // This triggers the necessary checks. - if (Nodes.size() < index) Nodes.resize(index); - return &Nodes[index-1]; - } - - /// isRelatedBy - true iff n1 op n2 - bool isRelatedBy(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree, - LatticeVal LV) { - if (n1 == n2) return LV & EQ_BIT; - - Node *N1 = node(n1); - Node::iterator I = N1->find(n2, Subtree), E = N1->end(); - if (I != E) return (I->LV & LV) == I->LV; - - return false; - } - - // The add* methods assume that your input is logically valid and may - // assertion-fail or infinitely loop if you attempt a contradiction. - - /// addInequality - Sets n1 op n2. - /// It is also an error to call this on an inequality that is already true. - void addInequality(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree, - LatticeVal LV1) { - assert(n1 != n2 && "A node can't be inequal to itself."); - - if (LV1 != NE) - assert(!isRelatedBy(n1, n2, Subtree, reversePredicate(LV1)) && - "Contradictory inequality."); - - // Suppose we're adding %n1 < %n2. Find all the %a < %n1 and - // add %a < %n2 too. This keeps the graph fully connected. - if (LV1 != NE) { - // Break up the relationship into signed and unsigned comparison parts. - // If the signed parts of %a op1 %n1 match that of %n1 op2 %n2, and - // op1 and op2 aren't NE, then add %a op3 %n2. The new relationship - // should have the EQ_BIT iff it's set for both op1 and op2. - - unsigned LV1_s = LV1 & (SLT_BIT|SGT_BIT); - unsigned LV1_u = LV1 & (ULT_BIT|UGT_BIT); - - for (Node::iterator I = node(n1)->begin(), E = node(n1)->end(); I != E; ++I) { - if (I->LV != NE && I->To != n2) { - - DomTreeDFS::Node *Local_Subtree = NULL; - if (Subtree->DominatedBy(I->Subtree)) - Local_Subtree = Subtree; - else if (I->Subtree->DominatedBy(Subtree)) - Local_Subtree = I->Subtree; - - if (Local_Subtree) { - unsigned new_relationship = 0; - LatticeVal ILV = reversePredicate(I->LV); - unsigned ILV_s = ILV & (SLT_BIT|SGT_BIT); - unsigned ILV_u = ILV & (ULT_BIT|UGT_BIT); - - if (LV1_s != (SLT_BIT|SGT_BIT) && ILV_s == LV1_s) - new_relationship |= ILV_s; - if (LV1_u != (ULT_BIT|UGT_BIT) && ILV_u == LV1_u) - new_relationship |= ILV_u; - - if (new_relationship) { - if ((new_relationship & (SLT_BIT|SGT_BIT)) == 0) - new_relationship |= (SLT_BIT|SGT_BIT); - if ((new_relationship & (ULT_BIT|UGT_BIT)) == 0) - new_relationship |= (ULT_BIT|UGT_BIT); - if ((LV1 & EQ_BIT) && (ILV & EQ_BIT)) - new_relationship |= EQ_BIT; - - LatticeVal NewLV = static_cast<LatticeVal>(new_relationship); - - node(I->To)->update(n2, NewLV, Local_Subtree); - node(n2)->update(I->To, reversePredicate(NewLV), Local_Subtree); - } - } - } - } - - for (Node::iterator I = node(n2)->begin(), E = node(n2)->end(); I != E; ++I) { - if (I->LV != NE && I->To != n1) { - DomTreeDFS::Node *Local_Subtree = NULL; - if (Subtree->DominatedBy(I->Subtree)) - Local_Subtree = Subtree; - else if (I->Subtree->DominatedBy(Subtree)) - Local_Subtree = I->Subtree; - - if (Local_Subtree) { - unsigned new_relationship = 0; - unsigned ILV_s = I->LV & (SLT_BIT|SGT_BIT); - unsigned ILV_u = I->LV & (ULT_BIT|UGT_BIT); - - if (LV1_s != (SLT_BIT|SGT_BIT) && ILV_s == LV1_s) - new_relationship |= ILV_s; - - if (LV1_u != (ULT_BIT|UGT_BIT) && ILV_u == LV1_u) - new_relationship |= ILV_u; - - if (new_relationship) { - if ((new_relationship & (SLT_BIT|SGT_BIT)) == 0) - new_relationship |= (SLT_BIT|SGT_BIT); - if ((new_relationship & (ULT_BIT|UGT_BIT)) == 0) - new_relationship |= (ULT_BIT|UGT_BIT); - if ((LV1 & EQ_BIT) && (I->LV & EQ_BIT)) - new_relationship |= EQ_BIT; - - LatticeVal NewLV = static_cast<LatticeVal>(new_relationship); - - node(n1)->update(I->To, NewLV, Local_Subtree); - node(I->To)->update(n1, reversePredicate(NewLV), Local_Subtree); - } - } - } - } - } - - node(n1)->update(n2, LV1, Subtree); - node(n2)->update(n1, reversePredicate(LV1), Subtree); - } - - /// remove - removes a node from the graph by removing all references to - /// and from it. - void remove(unsigned n) { - Node *N = node(n); - for (Node::iterator NI = N->begin(), NE = N->end(); NI != NE; ++NI) { - Node::iterator Iter = node(NI->To)->find(n, TreeRoot); - do { - node(NI->To)->Relations.erase(Iter); - Iter = node(NI->To)->find(n, TreeRoot); - } while (Iter != node(NI->To)->end()); - } - N->Relations.clear(); - } - -#ifndef NDEBUG - virtual ~InequalityGraph() {} - virtual void dump() { - dump(errs()); - } - - void dump(raw_ostream &os) { - for (unsigned i = 1; i <= Nodes.size(); ++i) { - os << i << " = {"; - node(i)->dump(os); - os << "}\n"; - } - } -#endif - }; - - class VRPSolver; - - /// ValueRanges tracks the known integer ranges and anti-ranges of the nodes - /// in the InequalityGraph. - class ValueRanges { - ValueNumbering &VN; - TargetData *TD; - LLVMContext *Context; - - class ScopedRange { - typedef std::vector<std::pair<DomTreeDFS::Node *, ConstantRange> > - RangeListType; - RangeListType RangeList; - - static bool swo(const std::pair<DomTreeDFS::Node *, ConstantRange> &LHS, - const std::pair<DomTreeDFS::Node *, ConstantRange> &RHS) { - return *LHS.first < *RHS.first; - } - - public: -#ifndef NDEBUG - virtual ~ScopedRange() {} - virtual void dump() const { - dump(errs()); - } - - void dump(raw_ostream &os) const { - os << "{"; - for (const_iterator I = begin(), E = end(); I != E; ++I) { - os << &I->second << " (" << I->first->getDFSNumIn() << "), "; - } - os << "}"; - } -#endif - - typedef RangeListType::iterator iterator; - typedef RangeListType::const_iterator const_iterator; - - iterator begin() { return RangeList.begin(); } - iterator end() { return RangeList.end(); } - const_iterator begin() const { return RangeList.begin(); } - const_iterator end() const { return RangeList.end(); } - - iterator find(DomTreeDFS::Node *Subtree) { - iterator E = end(); - iterator I = std::lower_bound(begin(), E, - std::make_pair(Subtree, empty), swo); - - while (I != E && !I->first->dominates(Subtree)) ++I; - return I; - } - - const_iterator find(DomTreeDFS::Node *Subtree) const { - const_iterator E = end(); - const_iterator I = std::lower_bound(begin(), E, - std::make_pair(Subtree, empty), swo); - - while (I != E && !I->first->dominates(Subtree)) ++I; - return I; - } - - void update(const ConstantRange &CR, DomTreeDFS::Node *Subtree) { - assert(!CR.isEmptySet() && "Empty ConstantRange."); - assert(!CR.isSingleElement() && "Refusing to store single element."); - - iterator E = end(); - iterator I = - std::lower_bound(begin(), E, std::make_pair(Subtree, empty), swo); - - if (I != end() && I->first == Subtree) { - ConstantRange CR2 = I->second.intersectWith(CR); - assert(!CR2.isEmptySet() && !CR2.isSingleElement() && - "Invalid union of ranges."); - I->second = CR2; - } else - RangeList.insert(I, std::make_pair(Subtree, CR)); - } - }; - - std::vector<ScopedRange> Ranges; - - void update(unsigned n, const ConstantRange &CR, DomTreeDFS::Node *Subt |