| //===-- PredicateSimplifier.cpp - Path Sensitive Simplifier ---------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by Nick Lewycky and 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/Compiler.h" |
| #include "llvm/Support/ConstantRange.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/InstVisitor.h" |
| #include "llvm/Target/TargetData.h" |
| #include "llvm/Transforms/Utils/Local.h" |
| #include <algorithm> |
| #include <deque> |
| #include <sstream> |
| #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"); |
| |
| 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); |
| } |
| } |
| |
| 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(*cerr.stream()); |
| } |
| |
| void dump(std::ostream &os) const { |
| os << "Predicate simplifier DomTreeDFS: \n"; |
| dump(Entry, 0, os); |
| os << "\n\n"; |
| } |
| |
| void dump(Node *N, int depth, std::ostream &os) const { |
| ++depth; |
| for (int i = 0; i < depth; ++i) { os << " "; } |
| os << "[" << depth << "] "; |
| |
| os << N->getBlock()->getName() << " (" << 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 |
| }; |
| |
| /// 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; |
| } |
| } |
| |
| /// 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 VISIBILITY_HIDDEN 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 VISIBILITY_HIDDEN 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() { |
| dump(*cerr.stream()); |
| } |
| |
| void dump(std::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::VoidTy) 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::VoidTy && "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 VISIBILITY_HIDDEN 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 VISIBILITY_HIDDEN 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 VISIBILITY_HIDDEN 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(*cerr.stream()); |
| } |
| private: |
| void dump(std::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(*cerr.stream()); |
| } |
| |
| void dump(std::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 VISIBILITY_HIDDEN ValueRanges { |
| ValueNumbering &VN; |
| TargetData *TD; |
| |
| class VISIBILITY_HIDDEN 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(*cerr.stream()); |
| } |
| |
| void dump(std::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) { |
| static ConstantRange empty(1, false); |
| 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 { |
| static const ConstantRange empty(1, false); |
| 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."); |
| |
| static ConstantRange empty(1, false); |
| 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.maximalIntersectWith(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 *Subtree){ |
| if (CR.isFullSet()) return; |
| if (Ranges.size() < n) Ranges.resize(n); |
| Ranges[n-1].update(CR, Subtree); |
| } |
| |
| /// create - Creates a ConstantRange that matches the given LatticeVal |
| /// relation with a given integer. |
| ConstantRange create(LatticeVal LV, const ConstantRange &CR) { |
| assert(!CR.isEmptySet() && "Can't deal with empty set."); |
| |
| if (LV == NE) |
| return makeConstantRange(ICmpInst::ICMP_NE, CR); |
| |
| unsigned LV_s = LV & (SGT_BIT|SLT_BIT); |
| unsigned LV_u = LV & (UGT_BIT|ULT_BIT); |
| bool hasEQ = LV & EQ_BIT; |
| |
| ConstantRange Range(CR.getBitWidth()); |
| |
| if (LV_s == SGT_BIT) { |
| Range = Range.maximalIntersectWith(makeConstantRange( |
| hasEQ ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_SGT, CR)); |
| } else if (LV_s == SLT_BIT) { |
| Range = Range.maximalIntersectWith(makeConstantRange( |
| hasEQ ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_SLT, CR)); |
| } |
| |
| if (LV_u == UGT_BIT) { |
| Range = Range.maximalIntersectWith(makeConstantRange( |
| hasEQ ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_UGT, CR)); |
| } else if (LV_u == ULT_BIT) { |
| Range = Range.maximalIntersectWith(makeConstantRange( |
| hasEQ ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_ULT, CR)); |
| } |
| |
| return Range; |
| } |
| |
| /// makeConstantRange - Creates a ConstantRange representing the set of all |
| /// value that match the ICmpInst::Predicate with any of the values in CR. |
| ConstantRange makeConstantRange(ICmpInst::Predicate ICmpOpcode, |
| const ConstantRange &CR) { |
| uint32_t W = CR.getBitWidth(); |
| switch (ICmpOpcode) { |
| default: assert(!"Invalid ICmp opcode to makeConstantRange()"); |
| case ICmpInst::ICMP_EQ: |
| return ConstantRange(CR.getLower(), CR.getUpper()); |
| case ICmpInst::ICMP_NE: |
| if (CR.isSingleElement()) |
| return ConstantRange(CR.getUpper(), CR.getLower()); |
| return ConstantRange(W); |
| case ICmpInst::ICMP_ULT: |
| return ConstantRange(APInt::getMinValue(W), CR.getUnsignedMax()); |
| case ICmpInst::ICMP_SLT: |
| return ConstantRange(APInt::getSignedMinValue(W), CR.getSignedMax()); |
| case ICmpInst::ICMP_ULE: { |
| APInt UMax(CR.getUnsignedMax()); |
| if (UMax.isMaxValue()) |
| return ConstantRange(W); |
| return ConstantRange(APInt::getMinValue(W), UMax + 1); |
| } |
| case ICmpInst::ICMP_SLE: { |
| APInt SMax(CR.getSignedMax()); |
| if (SMax.isMaxSignedValue() || (SMax+1).isMaxSignedValue()) |
| return ConstantRange(W); |
| return ConstantRange(APInt::getSignedMinValue(W), SMax + 1); |
| } |
| case ICmpInst::ICMP_UGT: |
| return ConstantRange(CR.getUnsignedMin() + 1, APInt::getNullValue(W)); |
| case ICmpInst::ICMP_SGT: |
| return ConstantRange(CR.getSignedMin() + 1, |
| APInt::getSignedMinValue(W)); |
| case ICmpInst::ICMP_UGE: { |
| APInt UMin(CR.getUnsignedMin()); |
| if (UMin.isMinValue()) |
| return ConstantRange(W); |
| return ConstantRange(UMin, APInt::getNullValue(W)); |
| } |
| case ICmpInst::ICMP_SGE: { |
| APInt SMin(CR.getSignedMin()); |
| if (SMin.isMinSignedValue()) |
| return ConstantRange(W); |
| return ConstantRange(SMin, APInt::getSignedMinValue(W)); |
| } |
| } |
| } |
| |
| #ifndef NDEBUG |
| bool isCanonical(Value *V, DomTreeDFS::Node *Subtree) { |
| return V == VN.canonicalize(V, Subtree); |
| } |
| #endif |
| |
| public: |
| |
| ValueRanges(ValueNumbering &VN, TargetData *TD) : VN(VN), TD(TD) {} |
| |
| #ifndef NDEBUG |
| virtual ~ValueRanges() {} |
| |
| virtual void dump() const { |
| dump(*cerr.stream()); |
| } |
| |
| void dump(std::ostream &os) const { |
| for (unsigned i = 0, e = Ranges.size(); i != e; ++i) { |
| os << (i+1) << " = "; |
| Ranges[i].dump(os); |
| os << "\n"; |
| } |
| } |
| #endif |
| |
| /// range - looks up the ConstantRange associated with a value number. |
| ConstantRange range(unsigned n, DomTreeDFS::Node *Subtree) { |
| assert(VN.value(n)); // performs range checks |
| |
| if (n <= Ranges.size()) { |
| ScopedRange::iterator I = Ranges[n-1].find(Subtree); |
| if (I != Ranges[n-1].end()) return I->second; |
| } |
| |
| Value *V = VN.value(n); |
| ConstantRange CR = range(V); |
| return CR; |
| } |
| |
| /// range - determine a range from a Value without performing any lookups. |
| ConstantRange range(Value *V) const { |
| if (ConstantInt *C = dyn_cast<ConstantInt>(V)) |
| return ConstantRange(C->getValue()); |
| else if (isa<ConstantPointerNull>(V)) |
| return ConstantRange(APInt::getNullValue(typeToWidth(V->getType()))); |
| else |
| return typeToWidth(V->getType()); |
| } |
| |
| // typeToWidth - returns the number of bits necessary to store a value of |
| // this type, or zero if unknown. |
| uint32_t typeToWidth(const Type *Ty) const { |
| if (TD) |
| return TD->getTypeSizeInBits(Ty); |
| else |
| return Ty->getPrimitiveSizeInBits(); |
| } |
| |
| static bool isRelatedBy(const ConstantRange &CR1, const ConstantRange &CR2, |
| LatticeVal LV) { |
| switch (LV) { |
| default: assert(!"Impossible lattice value!"); |
| case NE: |
| return CR1.maximalIntersectWith(CR2).isEmptySet(); |
| case ULT: |
| return CR1.getUnsignedMax().ult(CR2.getUnsignedMin()); |
| case ULE: |
| return CR1.getUnsignedMax().ule(CR2.getUnsignedMin()); |
| case UGT: |
| return CR1.getUnsignedMin().ugt(CR2.getUnsignedMax()); |
| case UGE: |
| return CR1.getUnsignedMin().uge(CR2.getUnsignedMax()); |
| case SLT: |
| return CR1.getSignedMax().slt(CR2.getSignedMin()); |
| case SLE: |
| return CR1.getSignedMax().sle(CR2.getSignedMin()); |
| case SGT: |
| return CR1.getSignedMin().sgt(CR2.getSignedMax()); |
| case SGE: |
| return CR1.getSignedMin().sge(CR2.getSignedMax()); |
| case LT: |
| return CR1.getUnsignedMax().ult(CR2.getUnsignedMin()) && |
| CR1.getSignedMax().slt(CR2.getUnsignedMin()); |
| case LE: |
| return CR1.getUnsignedMax().ule(CR2.getUnsignedMin()) && |
| CR1.getSignedMax().sle(CR2.getUnsignedMin()); |
| case GT: |
| return CR1.getUnsignedMin().ugt(CR2.getUnsignedMax()) && |
| CR1.getSignedMin().sgt(CR2.getSignedMax()); |
| case GE: |
| return CR1.getUnsignedMin().uge(CR2.getUnsignedMax()) && |
| CR1.getSignedMin().sge(CR2.getSignedMax()); |
| case SLTUGT: |
| return CR1.getSignedMax().slt(CR2.getSignedMin()) && |
| CR1.getUnsignedMin().ugt(CR2.getUnsignedMax()); |
| case SLEUGE: |
| return CR1.getSignedMax().sle(CR2.getSignedMin()) && |
| CR1.getUnsignedMin().uge(CR2.getUnsignedMax()); |
| case SGTULT: |
| return CR1.getSignedMin().sgt(CR2.getSignedMax()) && |
| CR1.getUnsignedMax().ult(CR2.getUnsignedMin()); |
| case SGEULE: |
| return CR1.getSignedMin().sge(CR2.getSignedMax()) && |
| CR1.getUnsignedMax().ule(CR2.getUnsignedMin()); |
| } |
| } |
| |
| bool isRelatedBy(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree, |
| LatticeVal LV) { |
| ConstantRange CR1 = range(n1, Subtree); |
| ConstantRange CR2 = range(n2, Subtree); |
| |
| // True iff all values in CR1 are LV to all values in CR2. |
| return isRelatedBy(CR1, CR2, LV); |
| } |
| |
| void addToWorklist(Value *V, Constant *C, ICmpInst::Predicate Pred, |
| VRPSolver *VRP); |
| void markBlock(VRPSolver *VRP); |
| |
| void mergeInto(Value **I, unsigned n, unsigned New, |
| DomTreeDFS::Node *Subtree, VRPSolver *VRP) { |
| ConstantRange CR_New = range(New, Subtree); |
| ConstantRange Merged = CR_New; |
| |
| for (; n != 0; ++I, --n) { |
| unsigned i = VN.valueNumber(*I, Subtree); |
| ConstantRange CR_Kill = i ? range(i, Subtree) : range(*I); |
| if (CR_Kill.isFullSet()) continue; |
| Merged = Merged.maximalIntersectWith(CR_Kill); |
| } |
| |
| if (Merged.isFullSet() || Merged == CR_New) return; |
| |
| applyRange(New, Merged, Subtree, VRP); |
| } |
| |
| void applyRange(unsigned n, const ConstantRange &CR, |
| DomTreeDFS::Node *Subtree, VRPSolver *VRP) { |
| ConstantRange Merged = CR.maximalIntersectWith(range(n, Subtree)); |
| if (Merged.isEmptySet()) { |
| markBlock(VRP); |
| return; |
| } |
| |
| if (const APInt *I = Merged.getSingleElement()) { |
| Value *V = VN.value(n); // XXX: redesign worklist. |
| const Type *Ty = V->getType(); |
| if (Ty->isInteger()) { |
| addToWorklist(V, ConstantInt::get(*I), ICmpInst::ICMP_EQ, VRP); |
| return; |
| } else if (const PointerType *PTy = dyn_cast<PointerType>(Ty)) { |
| assert(*I == 0 && "Pointer is null but not zero?"); |
| addToWorklist(V, ConstantPointerNull::get(PTy), |
| ICmpInst::ICMP_EQ, VRP); |
| return; |
| } |
| } |
| |
| update(n, Merged, Subtree); |
| } |
| |
| void addNotEquals(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree, |
| VRPSolver *VRP) { |
| ConstantRange CR1 = range(n1, Subtree); |
| ConstantRange CR2 = range(n2, Subtree); |
| |
| uint32_t W = CR1.getBitWidth(); |
| |
| if (const APInt *I = CR1.getSingleElement()) { |
| if (CR2.isFullSet()) { |
| ConstantRange NewCR2(CR1.getUpper(), CR1.getLower()); |
| applyRange(n2, NewCR2, Subtree, VRP); |
| } else if (*I == CR2.getLower()) { |
| APInt NewLower(CR2.getLower() + 1), |
| NewUpper(CR2.getUpper()); |
| if (NewLower == NewUpper) |
| NewLower = NewUpper = APInt::getMinValue(W); |
| |
| ConstantRange NewCR2(NewLower, NewUpper); |
| applyRange(n2, NewCR2, Subtree, VRP); |
| } else if (*I == CR2.getUpper() - 1) { |
| APInt NewLower(CR2.getLower()), |
| NewUpper(CR2.getUpper() - 1); |
| if (NewLower == NewUpper) |
| NewLower = NewUpper = APInt::getMinValue(W); |
| |
| ConstantRange NewCR2(NewLower, NewUpper); |
| applyRange(n2, NewCR2, Subtree, VRP); |
| } |
| } |
| |
| if (const APInt *I = CR2.getSingleElement()) { |
| if (CR1.isFullSet()) { |
| ConstantRange NewCR1(CR2.getUpper(), CR2.getLower()); |
| applyRange(n1, NewCR1, Subtree, VRP); |
| } else if (*I == CR1.getLower()) { |
| APInt NewLower(CR1.getLower() + 1), |
| NewUpper(CR1.getUpper()); |
| if (NewLower == NewUpper) |
| NewLower = NewUpper = APInt::getMinValue(W); |
| |
| ConstantRange NewCR1(NewLower, NewUpper); |
| applyRange(n1, NewCR1, Subtree, VRP); |
| } else if (*I == CR1.getUpper() - 1) { |
| APInt NewLower(CR1.getLower()), |
| NewUpper(CR1.getUpper() - 1); |
| if (NewLower == NewUpper) |
| NewLower = NewUpper = APInt::getMinValue(W); |
| |
| ConstantRange NewCR1(NewLower, NewUpper); |
| applyRange(n1, NewCR1, Subtree, VRP); |
| } |
| } |
| } |
| |
| void addInequality(unsigned n1, unsigned n2, DomTreeDFS::Node *Subtree, |
| LatticeVal LV, VRPSolver *VRP) { |
| assert(!isRelatedBy(n1, n2, Subtree, LV) && "Asked to do useless work."); |
| |
| if (LV == NE) { |
| addNotEquals(n1, n2, Subtree, VRP); |
| return; |
| } |
| |
| ConstantRange CR1 = range(n1, Subtree); |
| ConstantRange CR2 = range(n2, Subtree); |
| |
| if (!CR1.isSingleElement()) { |
| ConstantRange NewCR1 = CR1.maximalIntersectWith(create(LV, CR2)); |
| if (NewCR1 != CR1) |
| applyRange(n1, NewCR1, Subtree, VRP); |
| } |
| |
| if (!CR2.isSingleElement()) { |
| ConstantRange NewCR2 = CR2.maximalIntersectWith( |
| create(reversePredicate(LV), CR1)); |
| if (NewCR2 != CR2) |
| applyRange(n2, NewCR2, Subtree, VRP); |
| } |
| } |
| }; |
| |
| /// UnreachableBlocks keeps tracks of blocks that are for one reason or |
| /// another discovered to be unreachable. This is used to cull the graph when |
| /// analyzing instructions, and to mark blocks with the "unreachable" |
| /// terminator instruction after the function has executed. |
| class VISIBILITY_HIDDEN UnreachableBlocks { |
| private: |
| std::vector<BasicBlock *> DeadBlocks; |
| |
| public: |
| /// mark - mark a block as dead |
| void mark(BasicBlock *BB) { |
| std::vector<BasicBlock *>::iterator E = DeadBlocks.end(); |
| std::vector<BasicBlock *>::iterator I = |
| std::lower_bound(DeadBlocks.begin(), E, BB); |
| |
| if (I == E || *I != BB) DeadBlocks.insert(I, BB); |
| } |
| |
| /// isDead - returns whether a block is known to be dead already |
| bool isDead(BasicBlock *BB) { |
| std::vector<BasicBlock *>::iterator E = DeadBlocks.end(); |
| std::vector<BasicBlock *>::iterator I = |
| std::lower_bound(DeadBlocks.begin(), E, BB); |
| |
| return I != E && *I == BB; |
| } |
| |
| /// kill - replace the dead blocks' terminator with an UnreachableInst. |
| bool kill() { |
| bool modified = false; |
| for (std::vector<BasicBlock *>::iterator I = DeadBlocks.begin(), |
| E = DeadBlocks.end(); I != E; ++I) { |
| BasicBlock *BB = *I; |
| |
| DOUT << "unreachable block: " << BB->getName() << "\n"; |
| |
| for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); |
| SI != SE; ++SI) { |
| BasicBlock *Succ = *SI; |
| Succ->removePredecessor(BB); |
| } |
| |
| TerminatorInst *TI = BB->getTerminator(); |
| TI->replaceAllUsesWith(UndefValue::get(TI->getType())); |
| TI->eraseFromParent(); |
| new UnreachableInst(BB); |
| ++NumBlocks; |
| modified = true; |
| } |
| DeadBlocks.clear(); |
| return modified; |
| } |
| }; |
| |
| /// VRPSolver keeps track of how changes to one variable affect other |
| /// variables, and forwards changes along to the InequalityGraph. It |
| /// also maintains the correct choice for "canonical" in the IG. |
| /// @brief VRPSolver calculates inferences from a new relationship. |
| class VISIBILITY_HIDDEN VRPSolver { |
| private: |
| friend class ValueRanges; |
| |
| struct Operation { |
| Value *LHS, *RHS; |
| ICmpInst::Predicate Op; |
| |
| BasicBlock *ContextBB; // XXX use a DomTreeDFS::Node instead |
| Instruction *ContextInst; |
| }; |
| std::deque<Operation> WorkList; |
| |
| ValueNumbering &VN; |
| InequalityGraph &IG; |
| UnreachableBlocks &UB; |
| ValueRanges &VR; |
| DomTreeDFS *DTDFS; |
| DomTreeDFS::Node *Top; |
| BasicBlock *TopBB; |
| Instruction *TopInst; |
| bool &modified; |
| |
| typedef InequalityGraph::Node Node; |
| |
| // below - true if the Instruction is dominated by the current context |
| // block or instruction |
| bool below(Instruction *I) { |
| BasicBlock *BB = I->getParent(); |
| if (TopInst && TopInst->getParent() == BB) { |
| if (isa<TerminatorInst>(TopInst)) return false; |
| if (isa<TerminatorInst>(I)) return true; |
| if ( isa<PHINode>(TopInst) && !isa<PHINode>(I)) return true; |
| if (!isa<PHINode>(TopInst) && isa<PHINode>(I)) return false; |
| |
| for (BasicBlock::const_iterator Iter = BB->begin(), E = BB->end(); |
| Iter != E; ++Iter) { |
| if (&*Iter == TopInst) return true; |
| else if (&*Iter == I) return false; |
| } |
| assert(!"Instructions not found in parent BasicBlock?"); |
| } else { |
| DomTreeDFS::Node *Node = DTDFS->getNodeForBlock(BB); |
| if (!Node) return false; |
| return Top->dominates(Node); |
| } |
| } |
| |
| // aboveOrBelow - true if the Instruction either dominates or is dominated |
| // by the current context block or instruction |
| bool aboveOrBelow(Instruction *I) { |
| BasicBlock *BB = I->getParent(); |
| DomTreeDFS::Node *Node = DTDFS->getNodeForBlock(BB); |
| if (!Node) return false; |
| |
| return Top == Node || Top->dominates(Node) || Node->dominates(Top); |
| } |
| |
| bool makeEqual(Value *V1, Value *V2) { |
| DOUT << "makeEqual(" << *V1 << ", " << *V2 << ")\n"; |
| DOUT << "context is "; |
| if (TopInst) DOUT << "I: " << *TopInst << "\n"; |
| else DOUT << "BB: " << TopBB->getName() |
| << "(" << Top->getDFSNumIn() << ")\n"; |
| |
| assert(V1->getType() == V2->getType() && |
| "Can't make two values with different types equal."); |
| |
| if (V1 == V2) return true; |
| |
| if (isa<Constant>(V1) && isa<Constant>(V2)) |
| return false; |
| |
| unsigned n1 = VN.valueNumber(V1, Top), n2 = VN.valueNumber(V2, Top); |
| |
| if (n1 && n2) { |
| if (n1 == n2) return true; |
| if (IG.isRelatedBy(n1, n2, Top, NE)) return false; |
| } |
| |
| if (n1) assert(V1 == VN.value(n1) && "Value isn't canonical."); |
| if (n2) assert(V2 == VN.value(n2) && "Value isn't canonical."); |
| |
| assert(!VN.compare(V2, V1) && "Please order parameters to makeEqual."); |
| |
| assert(!isa<Constant>(V2) && "Tried to remove a constant."); |
| |
| SetVector<unsigned> Remove; |
| if (n2) Remove.insert(n2); |
| |
| if (n1 && n2) { |
| // Suppose we're being told that %x == %y, and %x <= %z and %y >= %z. |
| // We can't just merge %x and %y because the relationship with %z would |
| // be EQ and that's invalid. What we're doing is looking for any nodes |
| // %z such that %x <= %z and %y >= %z, and vice versa. |
| |
| Node::iterator end = IG.node(n2)->end(); |
| |
| // Find the intersection between N1 and N2 which is dominated by |
| // Top. If we find %x where N1 <= %x <= N2 (or >=) then add %x to |
| // Remove. |
| for (Node::iterator I = IG.node(n1)->begin(), E = IG.node(n1)->end(); |
| I != E; ++I) { |
| if (!(I->LV & EQ_BIT) || !Top->DominatedBy(I->Subtree)) continue; |
| |
| unsigned ILV_s = I->LV & (SLT_BIT|SGT_BIT); |
| unsigned ILV_u = I->LV & (ULT_BIT|UGT_BIT); |
| Node::iterator NI = IG.node(n2)->find(I->To, Top); |
| if (NI != end) { |
| LatticeVal NILV = reversePredicate(NI->LV); |
| unsigned NILV_s = NILV & (SLT_BIT|SGT_BIT); |
| unsigned NILV_u = NILV & (ULT_BIT|UGT_BIT); |
| |
| if ((ILV_s != (SLT_BIT|SGT_BIT) && ILV_s == NILV_s) || |
| (ILV_u != (ULT_BIT|UGT_BIT) && ILV_u == NILV_u)) |
| Remove.insert(I->To); |
| } |
| } |
| |
| // See if one of the nodes about to be removed is actually a better |
| // canonical choice than n1. |
| unsigned orig_n1 = n1; |
| SetVector<unsigned>::iterator DontRemove = Remove.end(); |
| for (SetVector<unsigned>::iterator I = Remove.begin()+1 /* skip n2 */, |
| E = Remove.end(); I != E; ++I) { |
| unsigned n = *I; |
| Value *V = VN.value(n); |
| if (VN.compare(V, V1)) { |
| V1 = V; |
| n1 = n; |
| DontRemove = I; |
| } |
| } |
| if (DontRemove != Remove.end()) { |
| unsigned n = *DontRemove; |
| Remove.remove(n); |
| Remove.insert(orig_n1); |
| } |
| } |
| |
| // We'd like to allow makeEqual on two values to perform a simple |
| // substitution without every creating nodes in the IG whenever possible. |
| // |
| // The first iteration through this loop operates on V2 before going |
| // through the Remove list and operating on those too. If all of the |
| // iterations performed simple replacements then we exit early. |
| bool mergeIGNode = false; |
| unsigned i = 0; |
| for (Value *R = V2; i == 0 || i < Remove.size(); ++i) { |
| if (i) R = VN.value(Remove[i]); // skip n2. |
| |
| // Try to replace the whole instruction. If we can, we're done. |
| Instruction *I2 = dyn_cast<Instruction>(R); |
| if (I2 && below(I2)) { |
| std::vector<Instruction *> ToNotify; |
| for (Value::use_iterator UI = R->use_begin(), UE = R->use_end(); |
| UI != UE;) { |
| Use &TheUse = UI.getUse(); |
| ++UI; |
| if (Instruction *I = dyn_cast<Instruction>(TheUse.getUser())) |
| ToNotify.push_back(I); |
| } |
| |
| DOUT << "Simply removing " << *I2 |
| << ", replacing with " << *V1 << "\n"; |
| I2->replaceAllUsesWith(V1); |
| // leave it dead; it'll get erased later. |
| ++NumInstruction; |
| modified = true; |
| |
| for (std::vector<Instruction *>::iterator II = ToNotify.begin(), |
| IE = ToNotify.end(); II != IE; ++II) { |
| opsToDef(*II); |
| } |
| |
| continue; |
| } |
| |
| // Otherwise, replace all dominated uses. |
| for (Value::use_iterator UI = R->use_begin(), UE = R->use_end(); |
| UI != UE;) { |
| Use &TheUse = UI.getUse(); |
| ++UI; |
| if (Instruction *I = dyn_cast<Instruction>(TheUse.getUser())) { |
| if (below(I)) { |
| TheUse.set(V1); |
| modified = true; |
| ++NumVarsReplaced; |
| opsToDef(I); |
| } |
| } |
| } |
| |
| // If that killed the instruction, stop here. |
| if (I2 && isInstructionTriviallyDead(I2)) { |
| DOUT << "Killed all uses of " << *I2 |
| << ", replacing with " << *V1 << "\n"; |
| continue; |
| } |
| |
| // If we make it to here, then we will need to create a node for N1. |
| // Otherwise, we can skip out early! |
| mergeIGNode = true; |
| } |
| |
| if (!isa<Constant>(V1)) { |
| if (Remove.empty()) { |
| VR.mergeInto(&V2, 1, VN.getOrInsertVN(V1, Top), Top, this); |
| } else { |
| std::vector<Value*> RemoveVals; |
| RemoveVals.reserve(Remove.size()); |
| |
| for (SetVector<unsigned>::iterator I = Remove.begin(), |
| E = Remove.end(); I != E; ++I) { |
| Value *V = VN.value(*I); |
| if (!V->use_empty()) |
| RemoveVals.push_back(V); |
| } |
| VR.mergeInto(&RemoveVals[0], RemoveVals.size(), |
| VN.getOrInsertVN(V1, Top), Top, this); |
| } |
| } |
| |
| if (mergeIGNode) { |
| // Create N1. |
| if (!n1) n1 = VN.getOrInsertVN(V1, Top); |
| |
| // Migrate relationships from removed nodes to N1. |
| for (SetVector<unsigned>::iterator I = Remove.begin(), E = Remove.end(); |
| I != E; ++I) { |
| unsigned n = *I; |
| for (Node::iterator NI = IG.node(n)->begin(), NE = IG.node(n)->end(); |
| NI != NE; ++NI) { |
| if (NI->Subtree->DominatedBy(Top)) { |
| if (NI->To == n1) { |
| assert((NI->LV & EQ_BIT) && "Node inequal to itself."); |
| continue; |
| } |
| if (Remove.count(NI->To)) |
| continue; |
| |
| IG.node(NI->To)->update(n1, reversePredicate(NI->LV), Top); |
| IG.node(n1)->update(NI->To, NI->LV, Top); |
| } |
| } |
| } |
| |
| // Point V2 (and all items in Remove) to N1. |
| if (!n2) |
| VN.addEquality(n1, V2, Top); |
| else { |
| for (SetVector<unsigned>::iterator I = Remove.begin(), |
| E = Remove.end(); I != E; ++I) { |
| VN.addEquality(n1, VN.value(*I), Top); |
| } |
| } |
| |
| // If !Remove.empty() then V2 = Remove[0]->getValue(). |
| // Even when Remove is empty, we still want to process V2. |
| i = 0; |
| for (Value *R = V2; i == 0 || i < Remove.size(); ++i) { |
| if (i) R = VN.value(Remove[i]); // skip n2. |
| |
| if (Instruction *I2 = dyn_cast<Instruction>(R)) { |
| if (aboveOrBelow(I2)) |
| defToOps(I2); |
| } |
| for (Value::use_iterator UI = V2->use_begin(), UE = V2->use_end(); |
| UI != UE;) { |
| Use &TheUse = UI.getUse(); |
| ++UI; |
| if (Instruction *I = dyn_cast<Instruction>(TheUse.getUser())) { |
| if (aboveOrBelow(I)) |
| opsToDef(I); |
| } |
| } |
| } |
| } |
| |
| // re-opsToDef all dominated users of V1. |
| if (Instruction *I = dyn_cast<Instruction>(V1)) { |
| for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); |
| UI != UE;) { |
| Use &TheUse = UI.getUse(); |
| ++UI; |
| Value *V = TheUse.getUser(); |
| if (!V->use_empty()) { |
| if (Instruction *Inst = dyn_cast<Instruction>(V)) { |
| if (aboveOrBelow(Inst)) |
| opsToDef(Inst); |
| } |
| } |
| } |
| } |
| |
| return true; |
| } |
| |
| /// cmpInstToLattice - converts an CmpInst::Predicate to lattice value |
| /// Requires that the lattice value be valid; does not accept ICMP_EQ. |
| static LatticeVal cmpInstToLattice(ICmpInst::Predicate Pred) { |
| switch (Pred) { |
| case ICmpInst::ICMP_EQ: |
| assert(!"No matching lattice value."); |
| return static_cast<LatticeVal>(EQ_BIT); |
| default: |
| assert(!"Invalid 'icmp' predicate."); |
| case ICmpInst::ICMP_NE: |
| return NE; |
| case ICmpInst::ICMP_UGT: |
| return UGT; |
| case ICmpInst::ICMP_UGE: |
| return UGE; |
| case ICmpInst::ICMP_ULT: |
| return ULT; |
| case ICmpInst::ICMP_ULE: |
| return ULE; |
| case ICmpInst::ICMP_SGT: |
| return SGT; |
| case ICmpInst::ICMP_SGE: |
| return SGE; |
| case ICmpInst::ICMP_SLT: |
| return SLT; |
| case ICmpInst::ICMP_SLE: |
| return SLE; |
| } |
| } |
| |
| public: |
| VRPSolver(ValueNumbering &VN, InequalityGraph &IG, UnreachableBlocks &UB, |
| ValueRanges &VR, DomTreeDFS *DTDFS, bool &modified, |
| BasicBlock *TopBB) |
| : VN(VN), |
| IG(IG), |
| UB(UB), |
| VR(VR), |
| DTDFS(DTDFS), |
| Top(DTDFS->getNodeForBlock(TopBB)), |
| TopBB(TopBB), |
| TopInst(NULL), |
| modified(modified) |
| { |
| assert(Top && "VRPSolver created for unreachable basic block."); |
| } |
| |
| VRPSolver(ValueNumbering &VN, InequalityGraph &IG, UnreachableBlocks &UB, |
| ValueRanges &VR, DomTreeDFS *DTDFS, bool &modified, |
| Instruction *TopInst) |
| : VN(VN), |
| IG(IG), |
| UB(UB), |
| VR(VR), |
| DTDFS(DTDFS), |
| Top(DTDFS->getNodeForBlock(TopInst->getParent())), |
| TopBB(TopInst->getParent()), |
| TopInst(TopInst), |
| modified(modified) |
| { |
| assert(Top && "VRPSolver created for unreachable basic block."); |
| assert(Top->getBlock() == TopInst->getParent() && "Context mismatch."); |
| } |
| |
| bool isRelatedBy(Value *V1, Value *V2, ICmpInst::Predicate Pred) const { |
| if (Constant *C1 = dyn_cast<Constant>(V1)) |
| if (Constant *C2 = dyn_cast<Constant>(V2)) |
| return ConstantExpr::getCompare(Pred, C1, C2) == |
| ConstantInt::getTrue(); |
| |
| unsigned n1 = VN.valueNumber(V1, Top); |
| unsigned n2 = VN.valueNumber(V2, Top); |
| |
| if (n1 && n2) { |
| if (n1 == n2) return Pred == ICmpInst::ICMP_EQ || |
| Pred == ICmpInst::ICMP_ULE || |
| Pred == ICmpInst::ICMP_UGE || |
| Pred == ICmpInst::ICMP_SLE || |
| Pred == ICmpInst::ICMP_SGE; |
| if (Pred == ICmpInst::ICMP_EQ) return false; |
| if (IG.isRelatedBy(n1, n2, Top, cmpInstToLattice(Pred))) return true; |
| if (VR.isRelatedBy(n1, n2, Top, cmpInstToLattice(Pred))) return true; |
| } |
| |
| if ((n1 && !n2 && isa<Constant>(V2)) || |
| (n2 && !n1 && isa<Constant>(V1))) { |
| ConstantRange CR1 = n1 ? VR.range(n1, Top) : VR.range(V1); |
| ConstantRange CR2 = n2 ? VR.range(n2, Top) : VR.range(V2); |
| |
| if (Pred == ICmpInst::ICMP_EQ) |
| return CR1.isSingleElement() && |
| CR1.getSingleElement() == CR2.getSingleElement(); |
| |
| return VR.isRelatedBy(CR1, CR2, cmpInstToLattice(Pred)); |
| } |
| if (Pred == ICmpInst::ICMP_EQ) return V1 == V2; |
| return false; |
| } |
| |
| /// add - adds a new property to the work queue |
| void add(Value *V1, Value *V2, ICmpInst::Predicate Pred, |
| Instruction *I = NULL) { |
| DOUT << "adding " << *V1 << " " << Pred << " " << *V2; |
| if (I) DOUT << " context: " << *I; |
| else DOUT << " default context (" << Top->getDFSNumIn() << ")"; |
| DOUT << "\n"; |
| |
| assert(V1->getType() == V2->getType() && |
| "Can't relate two values with different types."); |
| |
| WorkList.push_back(Operation()); |
| Operation &O = WorkList.back(); |
| O.LHS = V1, O.RHS = V2, O.Op = Pred, O.ContextInst = I; |
| O.ContextBB = I ? I->getParent() : TopBB; |
| } |
| |
| /// defToOps - Given an instruction definition that we've learned something |
| /// new about, find any new relationships between its operands. |
| void defToOps(Instruction *I) { |
| Instruction *NewContext = below(I) ? I : TopInst; |
| Value *Canonical = VN.canonicalize(I, Top); |
| |
| if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) { |
| const Type *Ty = BO->getType(); |
| assert(!Ty->isFPOrFPVector() && "Float in work queue!"); |
| |
| Value *Op0 = VN.canonicalize(BO->getOperand(0), Top); |
| Value *Op1 = VN.canonicalize(BO->getOperand(1), Top); |
| |
| // TODO: "and i32 -1, %x" EQ %y then %x EQ %y. |
| |
| switch (BO->getOpcode()) { |
| case Instruction::And: { |
| // "and i32 %a, %b" EQ -1 then %a EQ -1 and %b EQ -1 |
| ConstantInt *CI = ConstantInt::getAllOnesValue(Ty); |
| if (Canonical == CI) { |
| add(CI, Op0, ICmpInst::ICMP_EQ, NewContext); |
| add(CI, Op1, ICmpInst::ICMP_EQ, NewContext); |
| } |
| } break; |
| case Instruction::Or: { |
| // "or i32 %a, %b" EQ 0 then %a EQ 0 and %b EQ 0 |
| Constant *Zero = Constant::getNullValue(Ty); |
| if (Canonical == Zero) { |
| add(Zero, Op0, ICmpInst::ICMP_EQ, NewContext); |
| add(Zero, Op1, ICmpInst::ICMP_EQ, NewContext); |
| } |
| } break; |
| case Instruction::Xor: { |
| // "xor i32 %c, %a" EQ %b then %a EQ %c ^ %b |
| // "xor i32 %c, %a" EQ %c then %a EQ 0 |
| // "xor i32 %c, %a" NE %c then %a NE 0 |
| // Repeat the above, with order of operands reversed. |
| Value *LHS = Op0; |
| Value *RHS = Op1; |
| if (!isa<Constant>(LHS)) std::swap(LHS, RHS); |
| |
| if (ConstantInt *CI = dyn_cast<ConstantInt>(Canonical)) { |
| if (ConstantInt *Arg = dyn_cast<ConstantInt>(LHS)) { |
| add(RHS, ConstantInt::get(CI->getValue() ^ Arg->getValue()), |
| ICmpInst::ICMP_EQ, NewContext); |
| } |
| } |
| if (Canonical == LHS) { |
| if (isa<ConstantInt>(Canonical)) |
| add(RHS, Constant::getNullValue(Ty), ICmpInst::ICMP_EQ, |
| NewContext); |
| } else if (isRelatedBy(LHS, Canonical, ICmpInst::ICMP_NE)) { |
| add(RHS, Constant::getNullValue(Ty), ICmpInst::ICMP_NE, |
| NewContext); |
| } |
| } break; |
| default: |
| break; |
| } |
| } else if (ICmpInst *IC = dyn_cast<ICmpInst>(I)) { |
| // "icmp ult i32 %a, %y" EQ true then %a u< y |
| // etc. |
| |
| if (Canonical == ConstantInt::getTrue()) { |
| add(IC->getOperand(0), IC->getOperand(1), IC->getPredicate(), |
| NewContext); |
| } else if (Canonical == ConstantInt::getFalse()) { |
| add(IC->getOperand(0), IC->getOperand(1), |
| ICmpInst::getInversePredicate(IC->getPredicate()), NewContext); |
| } |
| } else if (SelectInst *SI = dyn_cast<SelectInst>(I)) { |
| if (I->getType()->isFPOrFPVector()) return; |
| |
| // Given: "%a = select i1 %x, i32 %b, i32 %c" |
| // %a EQ %b and %b NE %c then %x EQ true |
| // %a EQ %c and %b NE %c then %x EQ false |
| |
| Value *True = SI->getTrueValue(); |
| Value *False = SI->getFalseValue(); |
| if (isRelatedBy(True, False, ICmpInst::ICMP_NE)) { |
| if (Canonical == VN.canonicalize(True, Top) || |
| isRelatedBy(Canonical, False, ICmpInst::ICMP_NE)) |
| add(SI->getCondition(), ConstantInt::getTrue(), |
| ICmpInst::ICMP_EQ, NewContext); |
| else if (Canonical == VN.canonicalize(False, Top) || |
| isRelatedBy(Canonical, True, ICmpInst::ICMP_NE)) |
| add(SI->getCondition(), ConstantInt::getFalse(), |
| ICmpInst::ICMP_EQ, NewContext); |
| } |
| } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) { |
| for (GetElementPtrInst::op_iterator OI = GEPI->idx_begin(), |
| OE = GEPI->idx_end(); OI != OE; ++OI) { |
| ConstantInt *Op = dyn_cast<ConstantInt>(VN.canonicalize(*OI, Top)); |
| if (!Op || !Op->isZero()) return; |
| } |
| // TODO: The GEPI indices are all zero. Copy from definition to operand, |
| // jumping the type plane as needed. |
| if (isRelatedBy(GEPI, Constant::getNullValue(GEPI->getType()), |
| ICmpInst::ICMP_NE)) { |
| Value *Ptr = GEPI->getPointerOperand(); |
| add(Ptr, Constant::getNullValue(Ptr->getType()), ICmpInst::ICMP_NE, |
| NewContext); |
| } |
| } else if (CastInst *CI = dyn_cast<CastInst>(I)) { |
| const Type *SrcTy = CI->getSrcTy(); |
| |
| unsigned ci = VN.getOrInsertVN(CI, Top); |
| uint32_t W = VR.typeToWidth(SrcTy); |
| if (!W) return; |
| ConstantRange CR = VR.range(ci, Top); |
| |
| if (CR.isFullSet()) return; |
| |
| switch (CI->getOpcode()) { |
| default: break; |
| case Instruction::ZExt: |
| case Instruction::SExt: |
| VR.applyRange(VN.getOrInsertVN(CI->getOperand(0), Top), |
| CR.truncate(W), Top, this); |
| break; |
| case Instruction::BitCast: |
| VR.applyRange(VN.getOrInsertVN(CI->getOperand(0), Top), |
| CR, Top, this); |
| break; |
| } |
| } |
| } |
| |
| /// opsToDef - A new relationship was discovered involving one of this |
| /// instruction's operands. Find any new relationship involving the |
| /// definition, or another operand. |
| void opsToDef(Instruction *I) { |
| Instruction *NewContext = below(I) ? I : TopInst; |
| |
| if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) { |
| Value *Op0 = VN.canonicalize(BO->getOperand(0), Top); |
| Value *Op1 = VN.canonicalize(BO->getOperand(1), Top); |
| |
| if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0)) |
| if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) { |
| add(BO, ConstantExpr::get(BO->getOpcode(), CI0, CI1), |
| ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } |
| |
| // "%y = and i1 true, %x" then %x EQ %y |
| // "%y = or i1 false, %x" then %x EQ %y |
| // "%x = add i32 %y, 0" then %x EQ %y |
| // "%x = mul i32 %y, 0" then %x EQ 0 |
| |
| Instruction::BinaryOps Opcode = BO->getOpcode(); |
| const Type *Ty = BO->getType(); |
| assert(!Ty->isFPOrFPVector() && "Float in work queue!"); |
| |
| Constant *Zero = Constant::getNullValue(Ty); |
| ConstantInt *AllOnes = ConstantInt::getAllOnesValue(Ty); |
| |
| switch (Opcode) { |
| default: break; |
| case Instruction::LShr: |
| case Instruction::AShr: |
| case Instruction::Shl: |
| case Instruction::Sub: |
| if (Op1 == Zero) { |
| add(BO, Op0, ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } |
| break; |
| case Instruction::Or: |
| if (Op0 == AllOnes || Op1 == AllOnes) { |
| add(BO, AllOnes, ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } // fall-through |
| case Instruction::Xor: |
| case Instruction::Add: |
| if (Op0 == Zero) { |
| add(BO, Op1, ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } else if (Op1 == Zero) { |
| add(BO, Op0, ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } |
| break; |
| case Instruction::And: |
| if (Op0 == AllOnes) { |
| add(BO, Op1, ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } else if (Op1 == AllOnes) { |
| add(BO, Op0, ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } |
| // fall-through |
| case Instruction::Mul: |
| if (Op0 == Zero || Op1 == Zero) { |
| add(BO, Zero, ICmpInst::ICMP_EQ, NewContext); |
| return; |
| } |
| break; |
| } |
| |
| // "%x = add i32 %y, %z" and %x EQ %y then %z EQ 0 |
| // "%x = add i32 %y, %z" and %x EQ %z then %y EQ 0 |
| // "%x = shl i32 %y, %z" and %x EQ %y and %y NE 0 then %z EQ 0 |
| // "%x = udiv i32 %y, %z" and %x EQ %y then %z EQ 1 |
| |
| Value *Known = Op0, *Unknown = Op1, |
| *TheBO = VN.canonicalize(BO, Top); |
| if (Known != TheBO) std::swap(Known, Unknown); |
| if (Known == TheBO) { |
| switch (Opcode) { |
| default: break; |
| case Instruction::LShr: |
| case Instruction::AShr: |
| case Instruction::Shl: |
| if (!isRelatedBy(Known, Zero, ICmpInst::ICMP_NE)) break; |
| // otherwise, fall-through. |
| case Instruction::Sub: |
| if (Unknown == Op0) break; |
| // otherwise, fall-through. |
| case Instruction::Xor: |
| case Instruction::Add: |
| add(Unknown, Zero, ICmpInst::ICMP_EQ, NewContext); |
| break; |
| case Instruction::UDiv: |
| case Instruction::SDiv: |
| if (Unknown == Op1) break; |
| if (isRelatedBy(Known, Zero, ICmpInst::ICMP_NE)) { |
| Constant *One = ConstantInt::get(Ty, 1); |
| add(Unknown, One, ICmpInst::ICMP_EQ, NewContext); |
| } |
| break; |
| } |
| } |
| |
| // TODO: "%a = add i32 %b, 1" and %b > %z then %a >= %z. |
| |
| } else if (ICmpInst *IC = dyn_cast<ICmpInst>(I)) { |
| // "%a = icmp ult i32 %b, %c" and %b u< %c then %a EQ true |
| // "%a = icmp ult i32 %b, %c" and %b u>= %c then %a EQ false |
| // etc. |
| |
| Value *Op0 = VN.canonicalize(IC->getOperand(0), Top); |
| Value *Op1 = VN.canonicalize(IC->getOperand(1), Top); |
| |
| ICmpInst::Predicate Pred = IC->getPredicate(); |
| if (isRelatedBy(Op0, Op1, Pred)) |
| add(IC, ConstantInt::getTrue(), ICmpInst::ICMP_EQ, NewContext); |
| else if (isRelatedBy(Op0, Op1, ICmpInst::getInversePredicate(Pred))) |
| add(IC, ConstantInt::getFalse(), ICmpInst::ICMP_EQ, NewContext); |
| |
| } else if (SelectInst *SI = dyn_cast<SelectInst>(I)) { |
| if (I->getType()->isFPOrFPVector()) return; |
| |
| // Given: "%a = select i1 %x, i32 %b, i32 %c" |
| // %x EQ true then %a EQ %b |
| // %x EQ false then %a EQ %c |
| // %b EQ %c then %a EQ %b |
| |
| Value *Canonical = VN.canonicalize(SI->getCondition(), Top); |
| if (Canonical == ConstantInt::getTrue()) { |
| add(SI, SI->getTrueValue(), ICmpInst::ICMP_EQ, NewContext); |
| } else if (Canonical == ConstantInt::getFalse()) { |
| add(SI, SI->getFalseValue(), ICmpInst::ICMP_EQ, NewContext); |
| } else if (VN.canonicalize(SI->getTrueValue(), Top) == |
| VN.canonicalize(SI->getFalseValue(), Top)) { |
| add(SI, SI->getTrueValue(), ICmpInst::ICMP_EQ, NewContext); |
| } |
| } else if (CastInst *CI = dyn_cast<CastInst>(I)) { |
| const Type *DestTy = CI->getDestTy(); |
| if (DestTy->isFPOrFPVector()) return; |
| |
| Value *Op = VN.canonicalize(CI->getOperand(0), Top); |
| Instruction::CastOps Opcode = CI->getOpcode(); |
| |
| if (Constant *C = dyn_cast<Constant>(Op)) { |
| add(CI, ConstantExpr::getCast(Opcode, C, DestTy), |
| ICmpInst::ICMP_EQ, NewContext); |
| } |
| |
| uint32_t W = VR.typeToWidth(DestTy); |
| unsigned ci = VN.getOrInsertVN(CI, Top); |
| ConstantRange CR = VR.range(VN.getOrInsertVN(Op, Top), Top); |
| |
| if (!CR.isFullSet()) { |
| switch (Opcode) { |
| default: break; |
| case Instruction::ZExt: |
| VR.applyRange(ci, CR.zeroExtend(W), Top, this); |
| break; |
| case Instruction::SExt: |
| VR.applyRange(ci, CR.signExtend(W), Top, this); |
| break; |
| case Instruction::Trunc: { |
| ConstantRange Result = CR.truncate(W); |
| if (!Result.isFullSet()) |
| VR.applyRange(ci, Result, Top, this); |
| } break; |
| case Instruction::BitCast: |
| VR.applyRange(ci, CR, Top, this); |
| break; |
| // TODO: other casts? |
| } |
| } |
| } else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) { |
| for (GetElementPtrInst::op_iterator OI = GEPI->idx_begin(), |
| OE = GEPI->idx_end(); OI != OE; ++OI) { |
| ConstantInt *Op = dyn_cast<ConstantInt>(VN.canonicalize(*OI, Top)); |
| if (!Op || !Op->isZero()) return; |
| } |
| // TODO: The GEPI indices are all zero. Copy from operand to definition, |
| // jumping the type plane as needed. |
| Value *Ptr = GEPI->getPointerOperand(); |
| if (isRelatedBy(Ptr, Constant::getNullValue(Ptr->getType()), |
| ICmpInst::ICMP_NE)) { |
| add(GEPI, Constant::getNullValue(GEPI->getType()), ICmpInst::ICMP_NE, |
| NewContext); |
| } |
| } |
| } |
| |
| /// solve - process the work queue |
| void solve() { |
| //DOUT << "WorkList entry, size: " << WorkList.size() << "\n"; |
| while (!WorkList.empty()) { |
| //DOUT << "WorkList size: " << WorkList.size() << "\n"; |
| |
| Operation &O = WorkList.front(); |
| TopInst = O.ContextInst; |
| TopBB = O.ContextBB; |
| Top = DTDFS->getNodeForBlock(TopBB); // XXX move this into Context |
| |
| O.LHS = VN.canonicalize(O.LHS, Top); |
| O.RHS = VN.canonicalize(O.RHS, Top); |
| |
| assert(O.LHS == VN.canonicalize(O.LHS, Top) && "Canonicalize isn't."); |
| assert(O.RHS == VN.canonicalize(O.RHS, Top) && "Canonicalize isn't."); |
| |
| DOUT << "solving " << *O.LHS << " " << O.Op << " " << *O.RHS; |
| if (O.ContextInst) DOUT << " context inst: " << *O.ContextInst; |
| else DOUT << " context block: " << O.ContextBB->getName(); |
| DOUT << "\n"; |
| |
| DEBUG(VN.dump()); |
| DEBUG(IG.dump()); |
| DEBUG(VR.dump()); |
| |
| // If they're both Constant, skip it. Check for contradiction and mark |
| // the BB as unreachable if so. |
| if (Constant *CI_L = dyn_cast<Constant>(O.LHS)) { |
| if (Constant *CI_R = dyn_cast<Constant>(O.RHS)) { |
| if (ConstantExpr::getCompare(O.Op, CI_L, CI_R) == |
| ConstantInt::getFalse()) |
| UB.mark(TopBB); |
| |
| WorkList.pop_front(); |
| continue; |
| } |
| } |
| |
| if (VN.compare(O.LHS, O.RHS)) { |
| std::swap(O.LHS, O.RHS); |
| O.Op = ICmpInst::getSwappedPredicate(O.Op); |
| } |
| |
| if (O.Op == ICmpInst::ICMP_EQ) { |
| if (!makeEqual(O.RHS, O.LHS)) |
| UB.mark(TopBB); |
| } else { |
| LatticeVal LV = cmpInstToLattice(O.Op); |
| |
| if ((LV & EQ_BIT) && |
| isRelatedBy(O.LHS, O.RHS, ICmpInst::getSwappedPredicate(O.Op))) { |
| if (!makeEqual(O.RHS, O.LHS)) |
| UB.mark(TopBB); |
| } else { |
| if (isRelatedBy(O.LHS, O.RHS, ICmpInst::getInversePredicate(O.Op))){ |
| UB.mark(TopBB); |
| WorkList.pop_front(); |
| continue; |
| } |
| |
| unsigned n1 = VN.getOrInsertVN(O.LHS, Top); |
| unsigned n2 = VN.getOrInsertVN(O.RHS, Top); |
| |
| if (n1 == n2) { |
| if (O.Op != ICmpInst::ICMP_UGE && O.Op != ICmpInst::ICMP_ULE && |
| O.Op != ICmpInst::ICMP_SGE && O.Op != ICmpInst::ICMP_SLE) |
| UB.mark(TopBB); |
| |
| WorkList.pop_front(); |
| continue; |
| } |
| |
| if (VR.isRelatedBy(n1, n2, Top, LV) || |
| IG.isRelatedBy(n1, n2, Top, LV)) { |
| WorkList.pop_front(); |
| continue; |
| } |
| |
| VR.addInequality(n1, n2, Top, LV, this); |
| if ((!isa<ConstantInt>(O.RHS) && !isa<ConstantInt>(O.LHS)) || |
| LV == NE) |
| IG.addInequality(n1, n2, Top, LV); |
| |
| if (Instruction *I1 = dyn_cast<Instruction>(O.LHS)) { |
| if (aboveOrBelow(I1)) |
| defToOps(I1); |
| } |
| if (isa<Instruction>(O.LHS) || isa<Argument>(O.LHS)) { |
| for (Value::use_iterator UI = O.LHS->use_begin(), |
| UE = O.LHS->use_end(); UI != UE;) { |
| Use &TheUse = UI.getUse(); |
| ++UI; |
| if (Instruction *I = dyn_cast<Instruction>(TheUse.getUser())) { |
| if (aboveOrBelow(I)) |
| opsToDef(I); |
| } |
| } |
| } |
| if (Instruction *I2 = dyn_cast<Instruction>(O.RHS)) { |
| if (aboveOrBelow(I2)) |
| defToOps(I2); |
| } |
| if (isa<Instruction>(O.RHS) || isa<Argument>(O.RHS)) { |
| for (Value::use_iterator UI = O.RHS->use_begin(), |
| UE = O.RHS->use_end(); UI != UE;) { |
| Use &TheUse = UI.getUse(); |
| ++UI; |
| if (Instruction *I = dyn_cast<Instruction>(TheUse.getUser())) { |
| if (aboveOrBelow(I)) |
| opsToDef(I); |
| } |
| } |
| } |
| } |
| } |
| WorkList.pop_front(); |
| } |
| } |
| }; |
| |
| void ValueRanges::addToWorklist(Value *V, Constant *C, |
| ICmpInst::Predicate Pred, VRPSolver *VRP) { |
| VRP->add(V, C, Pred, VRP->TopInst); |
| } |
| |
| void ValueRanges::markBlock(VRPSolver *VRP) { |
| VRP->UB.mark(VRP->TopBB); |
| } |
| |
| /// PredicateSimplifier - This class is a simplifier that replaces |
| /// one equivalent variable with another. It also tracks what |
| /// can't be equal and will solve setcc instructions when possible. |
| /// @brief Root of the predicate simplifier optimization. |
| class VISIBILITY_HIDDEN PredicateSimplifier : public FunctionPass { |
| DomTreeDFS *DTDFS; |
| bool modified; |
| ValueNumbering *VN; |
| InequalityGraph *IG; |
| UnreachableBlocks UB; |
| ValueRanges *VR; |
| |
| std::vector<DomTreeDFS::Node *> WorkList; |
| |
| public: |
| static char ID; // Pass identification, replacement for typeid |
| PredicateSimplifier() : FunctionPass((intptr_t)&ID) {} |
| |
| bool runOnFunction(Function &F); |
| |
| virtual void getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.addRequiredID(BreakCriticalEdgesID); |
| AU.addRequired<DominatorTree>(); |
| AU.addRequired<TargetData>(); |
| AU.addPreserved<TargetData>(); |
| } |
| |
| private: |
| /// Forwards - Adds new properties to VRPSolver and uses them to |
| /// simplify instructions. Because new properties sometimes apply to |
| /// a transition from one BasicBlock to another, this will use the |
| /// PredicateSimplifier::proceedToSuccessor(s) interface to enter the |
| /// basic block. |
| /// @brief Performs abstract execution of the program. |
| class VISIBILITY_HIDDEN Forwards : public InstVisitor<Forwards> { |
| friend class InstVisitor<Forwards>; |
| PredicateSimplifier *PS; |
| DomTreeDFS::Node *DTNode; |
| |
| public: |
| ValueNumbering &VN; |
| InequalityGraph &IG; |
| UnreachableBlocks &UB; |
| ValueRanges &VR; |
| |
| Forwards(PredicateSimplifier *PS, DomTreeDFS::Node *DTNode) |
| : PS(PS), DTNode(DTNode), VN(*PS->VN), IG(*PS->IG), UB(PS->UB), |
| VR(*PS->VR) {} |
| |
| void visitTerminatorInst(TerminatorInst &TI); |
| void visitBranchInst(BranchInst &BI); |
| void visitSwitchInst(SwitchInst &SI); |
| |
| void visitAllocaInst(AllocaInst &AI); |
| void visitLoadInst(LoadInst &LI); |
| void visitStoreInst(StoreInst &SI); |
| |
| void visitSExtInst(SExtInst &SI); |
| void visitZExtInst(ZExtInst &ZI); |
| |
| void visitBinaryOperator(BinaryOperator &BO); |
| void visitICmpInst(ICmpInst &IC); |
| }; |
| |
| // Used by terminator instructions to proceed from the current basic |
| // block to the next. Verifies that "current" dominates "next", |
| // then calls visitBasicBlock. |
| void proceedToSuccessors(DomTreeDFS::Node *Current) { |
| for (DomTreeDFS::Node::iterator I = Current->begin(), |
| E = Current->end(); I != E; ++I) { |
| WorkList.push_back(*I); |
| } |
| } |
| |
| void proceedToSuccessor(DomTreeDFS::Node *Next) { |
| WorkList.push_back(Next); |
| } |
| |
| // Visits each instruction in the basic block. |
| void visitBasicBlock(DomTreeDFS::Node *Node) { |
| BasicBlock *BB = Node->getBlock(); |
| DOUT << "Entering Basic Block: " << BB->getName() |
| << " (" << Node->getDFSNumIn() << ")\n"; |
| for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) { |
| visitInstruction(I++, Node); |
| } |
| } |
| |
| // Tries to simplify each Instruction and add new properties. |
| void visitInstruction(Instruction *I, DomTreeDFS::Node *DT) { |
| DOUT << "Considering instruction " << *I << "\n"; |
| DEBUG(VN->dump()); |
| DEBUG(IG->dump()); |
| DEBUG(VR->dump()); |
| |
| // Sometimes instructions are killed in earlier analysis. |
| if (isInstructionTriviallyDead(I)) { |
| ++NumSimple; |
| modified = true; |
| if (unsigned n = VN->valueNumber(I, DTDFS->getRootNode())) |
| if (VN->value(n) == I) IG->remove(n); |
| VN->remove(I); |
| I->eraseFromParent(); |
| return; |
| } |
| |
| #ifndef NDEBUG |
| // Try to replace the whole instruction. |
| Value *V = VN->canonicalize(I, DT); |
| assert(V == I && "Late instruction canonicalization."); |
| if (V != I) { |
| modified = true; |
| ++NumInstruction; |
| DOUT << "Removing " << *I << ", replacing with " << *V << "\n"; |
| if (unsigned n = VN->valueNumber(I, DTDFS->getRootNode())) |
| if (VN->value(n) == I) IG->remove(n); |
| VN->remove(I); |
| I->replaceAllUsesWith(V); |
| I->eraseFromParent(); |
| return; |
| } |
| |
| // Try to substitute operands. |
| for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { |
| Value *Oper = I->getOperand(i); |
| Value *V = VN->canonicalize(Oper, DT); |
| assert(V == Oper && "Late operand canonicalization."); |
| if (V != Oper) { |
| modified = true; |
| ++NumVarsReplaced; |
| DOUT << "Resolving " << *I; |
| I->setOperand(i, V); |
| DOUT << " into " << *I; |
| } |
| } |
| #endif |
| |
| std::string name = I->getParent()->getName(); |
| DOUT << "push (%" << name << ")\n"; |
| Forwards visit(this, DT); |
| visit.visit(*I); |
| DOUT << "pop (%" << name << ")\n"; |
| } |
| }; |
| |
| bool PredicateSimplifier::runOnFunction(Function &F) { |
| DominatorTree *DT = &getAnalysis<DominatorTree>(); |
| DTDFS = new DomTreeDFS(DT); |
| TargetData *TD = &getAnalysis<TargetData>(); |
| |
| DOUT << "Entering Function: " << F.getName() << "\n"; |
| |
| modified = false; |
| DomTreeDFS::Node *Root = DTDFS->getRootNode(); |
| VN = new ValueNumbering(DTDFS); |
| IG = new InequalityGraph(*VN, Root); |
| VR = new ValueRanges(*VN, TD); |
| WorkList.push_back(Root); |
| |
| do { |
| DomTreeDFS::Node *DTNode = WorkList.back(); |
| WorkList.pop_back(); |
| if (!UB.isDead(DTNode->getBlock())) visitBasicBlock(DTNode); |
| } while (!WorkList.empty()); |
| |
| delete DTDFS; |
| delete VR; |
| delete IG; |
| |
| modified |= UB.kill(); |
| |
| return modified; |
| } |
| |
| void PredicateSimplifier::Forwards::visitTerminatorInst(TerminatorInst &TI) { |
| PS->proceedToSuccessors(DTNode); |
| } |
| |
| void PredicateSimplifier::Forwards::visitBranchInst(BranchInst &BI) { |
| if (BI.isUnconditional()) { |
| PS->proceedToSuccessors(DTNode); |
| return; |
| } |
| |
| Value *Condition = BI.getCondition(); |
| BasicBlock *TrueDest = BI.getSuccessor(0); |
| BasicBlock *FalseDest = BI.getSuccessor(1); |
| |
| if (isa<Constant>(Condition) || TrueDest == FalseDest) { |
| PS->proceedToSuccessors(DTNode); |
| return; |
| } |
| |
| for (DomTreeDFS::Node::iterator I = DTNode->begin(), E = DTNode->end(); |
| I != E; ++I) { |
| BasicBlock *Dest = (*I)->getBlock(); |
| DOUT << "Branch thinking about %" << Dest->getName() |
| << "(" << PS->DTDFS->getNodeForBlock(Dest)->getDFSNumIn() << ")\n"; |
| |
| if (Dest == TrueDest) { |
| DOUT << "(" << DTNode->getBlock()->getName() << ") true set:\n"; |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, Dest); |
| VRP.add(ConstantInt::getTrue(), Condition, ICmpInst::ICMP_EQ); |
| VRP.solve(); |
| DEBUG(VN.dump()); |
| DEBUG(IG.dump()); |
| DEBUG(VR.dump()); |
| } else if (Dest == FalseDest) { |
| DOUT << "(" << DTNode->getBlock()->getName() << ") false set:\n"; |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, Dest); |
| VRP.add(ConstantInt::getFalse(), Condition, ICmpInst::ICMP_EQ); |
| VRP.solve(); |
| DEBUG(VN.dump()); |
| DEBUG(IG.dump()); |
| DEBUG(VR.dump()); |
| } |
| |
| PS->proceedToSuccessor(*I); |
| } |
| } |
| |
| void PredicateSimplifier::Forwards::visitSwitchInst(SwitchInst &SI) { |
| Value *Condition = SI.getCondition(); |
| |
| // Set the EQProperty in each of the cases BBs, and the NEProperties |
| // in the default BB. |
| |
| for (DomTreeDFS::Node::iterator I = DTNode->begin(), E = DTNode->end(); |
| I != E; ++I) { |
| BasicBlock *BB = (*I)->getBlock(); |
| DOUT << "Switch thinking about BB %" << BB->getName() |
| << "(" << PS->DTDFS->getNodeForBlock(BB)->getDFSNumIn() << ")\n"; |
| |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, BB); |
| if (BB == SI.getDefaultDest()) { |
| for (unsigned i = 1, e = SI.getNumCases(); i < e; ++i) |
| if (SI.getSuccessor(i) != BB) |
| VRP.add(Condition, SI.getCaseValue(i), ICmpInst::ICMP_NE); |
| VRP.solve(); |
| } else if (ConstantInt *CI = SI.findCaseDest(BB)) { |
| VRP.add(Condition, CI, ICmpInst::ICMP_EQ); |
| VRP.solve(); |
| } |
| PS->proceedToSuccessor(*I); |
| } |
| } |
| |
| void PredicateSimplifier::Forwards::visitAllocaInst(AllocaInst &AI) { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &AI); |
| VRP.add(Constant::getNullValue(AI.getType()), &AI, ICmpInst::ICMP_NE); |
| VRP.solve(); |
| } |
| |
| void PredicateSimplifier::Forwards::visitLoadInst(LoadInst &LI) { |
| Value *Ptr = LI.getPointerOperand(); |
| // avoid "load uint* null" -> null NE null. |
| if (isa<Constant>(Ptr)) return; |
| |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &LI); |
| VRP.add(Constant::getNullValue(Ptr->getType()), Ptr, ICmpInst::ICMP_NE); |
| VRP.solve(); |
| } |
| |
| void PredicateSimplifier::Forwards::visitStoreInst(StoreInst &SI) { |
| Value *Ptr = SI.getPointerOperand(); |
| if (isa<Constant>(Ptr)) return; |
| |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &SI); |
| VRP.add(Constant::getNullValue(Ptr->getType()), Ptr, ICmpInst::ICMP_NE); |
| VRP.solve(); |
| } |
| |
| void PredicateSimplifier::Forwards::visitSExtInst(SExtInst &SI) { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &SI); |
| uint32_t SrcBitWidth = cast<IntegerType>(SI.getSrcTy())->getBitWidth(); |
| uint32_t DstBitWidth = cast<IntegerType>(SI.getDestTy())->getBitWidth(); |
| APInt Min(APInt::getHighBitsSet(DstBitWidth, DstBitWidth-SrcBitWidth+1)); |
| APInt Max(APInt::getLowBitsSet(DstBitWidth, SrcBitWidth-1)); |
| VRP.add(ConstantInt::get(Min), &SI, ICmpInst::ICMP_SLE); |
| VRP.add(ConstantInt::get(Max), &SI, ICmpInst::ICMP_SGE); |
| VRP.solve(); |
| } |
| |
| void PredicateSimplifier::Forwards::visitZExtInst(ZExtInst &ZI) { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &ZI); |
| uint32_t SrcBitWidth = cast<IntegerType>(ZI.getSrcTy())->getBitWidth(); |
| uint32_t DstBitWidth = cast<IntegerType>(ZI.getDestTy())->getBitWidth(); |
| APInt Max(APInt::getLowBitsSet(DstBitWidth, SrcBitWidth)); |
| VRP.add(ConstantInt::get(Max), &ZI, ICmpInst::ICMP_UGE); |
| VRP.solve(); |
| } |
| |
| void PredicateSimplifier::Forwards::visitBinaryOperator(BinaryOperator &BO) { |
| Instruction::BinaryOps ops = BO.getOpcode(); |
| |
| switch (ops) { |
| default: break; |
| case Instruction::URem: |
| case Instruction::SRem: |
| case Instruction::UDiv: |
| case Instruction::SDiv: { |
| Value *Divisor = BO.getOperand(1); |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO); |
| VRP.add(Constant::getNullValue(Divisor->getType()), Divisor, |
| ICmpInst::ICMP_NE); |
| VRP.solve(); |
| break; |
| } |
| } |
| |
| switch (ops) { |
| default: break; |
| case Instruction::Shl: { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO); |
| VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_UGE); |
| VRP.solve(); |
| } break; |
| case Instruction::AShr: { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO); |
| VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_SLE); |
| VRP.solve(); |
| } break; |
| case Instruction::LShr: |
| case Instruction::UDiv: { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO); |
| VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_ULE); |
| VRP.solve(); |
| } break; |
| case Instruction::URem: { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO); |
| VRP.add(&BO, BO.getOperand(1), ICmpInst::ICMP_ULE); |
| VRP.solve(); |
| } break; |
| case Instruction::And: { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO); |
| VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_ULE); |
| VRP.add(&BO, BO.getOperand(1), ICmpInst::ICMP_ULE); |
| VRP.solve(); |
| } break; |
| case Instruction::Or: { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &BO); |
| VRP.add(&BO, BO.getOperand(0), ICmpInst::ICMP_UGE); |
| VRP.add(&BO, BO.getOperand(1), ICmpInst::ICMP_UGE); |
| VRP.solve(); |
| } break; |
| } |
| } |
| |
| void PredicateSimplifier::Forwards::visitICmpInst(ICmpInst &IC) { |
| // If possible, squeeze the ICmp predicate into something simpler. |
| // Eg., if x = [0, 4) and we're being asked icmp uge %x, 3 then change |
| // the predicate to eq. |
| |
| // XXX: once we do full PHI handling, modifying the instruction in the |
| // Forwards visitor will cause missed optimizations. |
| |
| ICmpInst::Predicate Pred = IC.getPredicate(); |
| |
| switch (Pred) { |
| default: break; |
| case ICmpInst::ICMP_ULE: Pred = ICmpInst::ICMP_ULT; break; |
| case ICmpInst::ICMP_UGE: Pred = ICmpInst::ICMP_UGT; break; |
| case ICmpInst::ICMP_SLE: Pred = ICmpInst::ICMP_SLT; break; |
| case ICmpInst::ICMP_SGE: Pred = ICmpInst::ICMP_SGT; break; |
| } |
| if (Pred != IC.getPredicate()) { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &IC); |
| if (VRP.isRelatedBy(IC.getOperand(1), IC.getOperand(0), |
| ICmpInst::ICMP_NE)) { |
| ++NumSnuggle; |
| PS->modified = true; |
| IC.setPredicate(Pred); |
| } |
| } |
| |
| Pred = IC.getPredicate(); |
| |
| if (ConstantInt *Op1 = dyn_cast<ConstantInt>(IC.getOperand(1))) { |
| ConstantInt *NextVal = 0; |
| switch (Pred) { |
| default: break; |
| case ICmpInst::ICMP_SLT: |
| case ICmpInst::ICMP_ULT: |
| if (Op1->getValue() != 0) |
| NextVal = ConstantInt::get(Op1->getValue()-1); |
| break; |
| case ICmpInst::ICMP_SGT: |
| case ICmpInst::ICMP_UGT: |
| if (!Op1->getValue().isAllOnesValue()) |
| NextVal = ConstantInt::get(Op1->getValue()+1); |
| break; |
| |
| } |
| if (NextVal) { |
| VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &IC); |
| if (VRP.isRelatedBy(IC.getOperand(0), NextVal, |
| ICmpInst::getInversePredicate(Pred))) { |
| ICmpInst *NewIC = new ICmpInst(ICmpInst::ICMP_EQ, IC.getOperand(0), |
| NextVal, "", &IC); |
| NewIC->takeName(&IC); |
| IC.replaceAllUsesWith(NewIC); |
| |
| // XXX: prove this isn't necessary |
| if (unsigned n = VN.valueNumber(&IC, PS->DTDFS->getRootNode())) |
| if (VN.value(n) == &IC) IG.remove(n); |
| VN.remove(&IC); |
| |
| IC.eraseFromParent(); |
| ++NumSnuggle; |
| PS->modified = true; |
| } |
| } |
| } |
| } |
| |
| char PredicateSimplifier::ID = 0; |
| RegisterPass<PredicateSimplifier> X("predsimplify", |
| "Predicate Simplifier"); |
| } |
| |
| FunctionPass *llvm::createPredicateSimplifierPass() { |
| return new PredicateSimplifier(); |
| } |