+++ /dev/null
-//===-- 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 *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 ConstantRange::makeICmpRegion(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.intersectWith(ConstantRange::makeICmpRegion(
- hasEQ ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_SGT, CR));
- } else if (LV_s == SLT_BIT) {
- Range = Range.intersectWith(ConstantRange::makeICmpRegion(
- hasEQ ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_SLT, CR));
- }
-
- if (LV_u == UGT_BIT) {
- Range = Range.intersectWith(ConstantRange::makeICmpRegion(
- hasEQ ? ICmpInst::ICMP_UGE : ICmpInst::ICMP_UGT, CR));
- } else if (LV_u == ULT_BIT) {
- Range = Range.intersectWith(ConstantRange::makeICmpRegion(
- hasEQ ? ICmpInst::ICMP_ULE : ICmpInst::ICMP_ULT, CR));
- }
-
- return Range;
- }
-
-#ifndef NDEBUG
- bool isCanonical(Value *V, DomTreeDFS::Node *Subtree) {
- return V == VN.canonicalize(V, Subtree);
- }
-#endif
-
- public:
-
- ValueRanges(ValueNumbering &VN, TargetData *TD, LLVMContext *C) :
- VN(VN), TD(TD), Context(C) {}
-
-#ifndef NDEBUG
- virtual ~ValueRanges() {}
-
- virtual void dump() const {
- dump(errs());
- }
-
- void dump(raw_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 ConstantRange(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.intersectWith(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.intersectWith(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.intersectWith(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(*Context, *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.intersectWith(create(LV, CR2));
- if (NewCR1 != CR1)
- applyRange(n1, NewCR1, Subtree, VRP);
- }
-
- if (!CR2.isSingleElement()) {
- ConstantRange NewCR2 = CR2.intersectWith(
- 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 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;
-
- DEBUG(errs() << "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->getContext(), 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 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;
- LLVMContext *Context;
-
- 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);
- }
- return false; // Not reached
- }
-
- // 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) {
- DEBUG(errs() << "makeEqual(" << *V1 << ", " << *V2 << ")\n");
- DEBUG(errs() << "context is ");
- DEBUG(if (TopInst)
- errs() << "I: " << *TopInst << "\n";
- else
- errs() << "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 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 = I2->use_begin(), UE = I2->use_end();
- UI != UE;) {
- Use &TheUse = UI.getUse();
- ++UI;
- Instruction *I = cast<Instruction>(TheUse.getUser());
- ToNotify.push_back(I);
- }
-
- DEBUG(errs() << "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)) {
- DEBUG(errs() << "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);
- IG.node(n1); // Ensure that IG.Nodes won't get resized
-
- // 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()) {
- Instruction *Inst = 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),
- Context(&TopBB->getContext())
- {
- 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),
- Context(&TopInst->getContext())
- {
- 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(*Context);
-
- 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) {
- DEBUG(errs() << "adding " << *V1 << " " << Pred << " " << *V2);
- if (I)
- DEBUG(errs() << " context: " << *I);
- else
- DEBUG(errs() << " default context (" << Top->getDFSNumIn() << ")");
- DEBUG(errs() << "\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 = cast<ConstantInt>(Constant::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(*Context, 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(*Context)) {
- add(IC->getOperand(0), IC->getOperand(1), IC->getPredicate(),
- NewContext);
- } else if (Canonical == ConstantInt::getFalse(*Context)) {
- 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(*Context),
- ICmpInst::ICMP_EQ, NewContext);
- else if (Canonical == VN.canonicalize(False, Top) ||
- isRelatedBy(Canonical, True, ICmpInst::ICMP_NE))
- add(SI->getCondition(), ConstantInt::getFalse(*Context),
- 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);
- Constant *One = ConstantInt::get(Ty, 1);
- ConstantInt *AllOnes = cast<ConstantInt>(Constant::getAllOnesValue(Ty));
-
- switch (Opcode) {
- default: break;
- case Instruction::LShr:
- case Instruction::AShr:
- case Instruction::Shl:
- if (Op1 == Zero) {
- add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
- return;
- }
- break;
- case Instruction::Sub:
- if (Op1 == Zero) {
- add(BO, Op0, ICmpInst::ICMP_EQ, NewContext);
- return;
- }
- if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0)) {
- unsigned n_ci0 = VN.getOrInsertVN(Op1, Top);
- ConstantRange CR = VR.range(n_ci0, Top);
- if (!CR.isFullSet()) {
- CR.subtract(CI0->getValue());
- unsigned n_bo = VN.getOrInsertVN(BO, Top);
- VR.applyRange(n_bo, CR, Top, this);
- return;
- }
- }
- if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) {
- unsigned n_ci1 = VN.getOrInsertVN(Op0, Top);
- ConstantRange CR = VR.range(n_ci1, Top);
- if (!CR.isFullSet()) {
- CR.subtract(CI1->getValue());
- unsigned n_bo = VN.getOrInsertVN(BO, Top);
- VR.applyRange(n_bo, CR, Top, this);
- return;
- }
- }
- break;
- case Instruction::Or:
- if (Op0 == AllOnes || Op1 == AllOnes) {
- add(BO, AllOnes, ICmpInst::ICMP_EQ, NewContext);
- return;
- }
- 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::Add:
- if (ConstantInt *CI0 = dyn_cast<ConstantInt>(Op0)) {
- unsigned n_ci0 = VN.getOrInsertVN(Op1, Top);
- ConstantRange CR = VR.range(n_ci0, Top);
- if (!CR.isFullSet()) {
- CR.subtract(-CI0->getValue());
- unsigned n_bo = VN.getOrInsertVN(BO, Top);
- VR.applyRange(n_bo, CR, Top, this);
- return;
- }
- }
- if (ConstantInt *CI1 = dyn_cast<ConstantInt>(Op1)) {
- unsigned n_ci1 = VN.getOrInsertVN(Op0, Top);
- ConstantRange CR = VR.range(n_ci1, Top);
- if (!CR.isFullSet()) {
- CR.subtract(-CI1->getValue());
- unsigned n_bo = VN.getOrInsertVN(BO, Top);
- VR.applyRange(n_bo, CR, Top, this);
- return;
- }
- }
- // fall-through
- case Instruction::Xor:
- 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;
- }
- if (Op0 == Zero || Op1 == Zero) {
- add(BO, Zero, ICmpInst::ICMP_EQ, NewContext);
- return;
- }
- break;
- case Instruction::Mul:
- if (Op0 == Zero || Op1 == Zero) {
- add(BO, Zero, ICmpInst::ICMP_EQ, NewContext);
- return;
- }
- if (Op0 == One) {
- add(BO, Op1, ICmpInst::ICMP_EQ, NewContext);
- return;
- } else if (Op1 == One) {
- add(BO, Op0, 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 and %y NE 0 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))
- 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(*Context), ICmpInst::ICMP_EQ, NewContext);
- else if (isRelatedBy(Op0, Op1, ICmpInst::getInversePredicate(Pred)))
- add(IC, ConstantInt::getFalse(*Context),
- 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(*Context)) {
- add(SI, SI->getTrueValue(), ICmpInst::ICMP_EQ, NewContext);
- } else if (Canonical == ConstantInt::getFalse(*Context)) {
- 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() {
- //DEBUG(errs() << "WorkList entry, size: " << WorkList.size() << "\n");
- while (!WorkList.empty()) {
- //DEBUG(errs() << "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.");
-
- DEBUG(errs() << "solving " << *O.LHS << " " << O.Op << " " << *O.RHS;
- if (O.ContextInst)
- errs() << " context inst: " << *O.ContextInst;
- else
- errs() << " context block: " << O.ContextBB->getName();
- errs() << "\n";
-
- VN.dump();
- IG.dump();
- 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(*Context))
- 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;
- Instruction *I = 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;
- Instruction *I = 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 PredicateSimplifier : public FunctionPass {
- DomTreeDFS *DTDFS;
- bool modified;
- ValueNumbering *VN;
- InequalityGraph *IG;
- UnreachableBlocks UB;
- ValueRanges *VR;
-
- std::vector<DomTreeDFS::Node *> WorkList;
-
- LLVMContext *Context;
- public:
- static char ID; // Pass identification, replacement for typeid
- PredicateSimplifier() : FunctionPass(&ID) {}
-
- bool runOnFunction(Function &F);
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequiredID(BreakCriticalEdgesID);
- AU.addRequired<DominatorTree>();
- }
-
- 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 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();
- DEBUG(errs() << "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) {
- DEBUG(errs() << "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;
- DEBUG(errs() << "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;
- DEBUG(errs() << "Resolving " << *I);
- I->setOperand(i, V);
- DEBUG(errs() << " into " << *I);
- }
- }
-#endif
-
- std::string name = I->getParent()->getName();
- DEBUG(errs() << "push (%" << name << ")\n");
- Forwards visit(this, DT);
- visit.visit(*I);
- DEBUG(errs() << "pop (%" << name << ")\n");
- }
- };
-
- bool PredicateSimplifier::runOnFunction(Function &F) {
- DominatorTree *DT = &getAnalysis<DominatorTree>();
- DTDFS = new DomTreeDFS(DT);
- TargetData *TD = getAnalysisIfAvailable<TargetData>();
-
- // FIXME: PredicateSimplifier should still be able to do basic
- // optimizations without TargetData. But for now, just exit if
- // it's not available.
- if (!TD) return false;
-
- Context = &F.getContext();
-
- DEBUG(errs() << "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, Context);
- 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;
- delete VN;
-
- 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;
- }
-
- LLVMContext *Context = &BI.getContext();
-
- for (DomTreeDFS::Node::iterator I = DTNode->begin(), E = DTNode->end();
- I != E; ++I) {
- BasicBlock *Dest = (*I)->getBlock();
- DEBUG(errs() << "Branch thinking about %" << Dest->getName()
- << "(" << PS->DTDFS->getNodeForBlock(Dest)->getDFSNumIn() << ")\n");
-
- if (Dest == TrueDest) {
- DEBUG(errs() << "(" << DTNode->getBlock()->getName()
- << ") true set:\n");
- VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, Dest);
- VRP.add(ConstantInt::getTrue(*Context), Condition, ICmpInst::ICMP_EQ);
- VRP.solve();
- DEBUG(VN.dump());
- DEBUG(IG.dump());
- DEBUG(VR.dump());
- } else if (Dest == FalseDest) {
- DEBUG(errs() << "(" << DTNode->getBlock()->getName()
- << ") false set:\n");
- VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, Dest);
- VRP.add(ConstantInt::getFalse(*Context), 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();
- DEBUG(errs() << "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 i8* 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);
- LLVMContext &Context = SI.getContext();
- 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(Context, Min), &SI, ICmpInst::ICMP_SLE);
- VRP.add(ConstantInt::get(Context, Max), &SI, ICmpInst::ICMP_SGE);
- VRP.solve();
- }
-
- void PredicateSimplifier::Forwards::visitZExtInst(ZExtInst &ZI) {
- VRPSolver VRP(VN, IG, UB, VR, PS->DTDFS, PS->modified, &ZI);
- LLVMContext &Context = ZI.getContext();
- 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(Context, 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();
-
- LLVMContext &Context = IC.getContext();
-
- 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(Context, Op1->getValue()-1);
- break;
- case ICmpInst::ICMP_SGT:
- case ICmpInst::ICMP_UGT:
- if (!Op1->getValue().isAllOnesValue())
- NextVal = ConstantInt::get(Context, 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(&IC, ICmpInst::ICMP_EQ,
- IC.getOperand(0), NextVal, "");
- 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;
-static RegisterPass<PredicateSimplifier>
-X("predsimplify", "Predicate Simplifier");
-
-FunctionPass *llvm::createPredicateSimplifierPass() {
- return new PredicateSimplifier();
-}
projects / oota-llvm.git / commitdiff