mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-15 04:30:12 +00:00
Replace EquivalenceClasses with a custom-built data structure. Many common
operations (like findProperties) should be faster, at the expense of unionSets being slower in cases that are rare in practise. Don't erase a dead Instruction. This fixes a memory corruption issue. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30235 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky
parent
2a86f3b744
commit
dc08cd56c4
@ -33,7 +33,6 @@
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#include "llvm/Constants.h"
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#include "llvm/Instructions.h"
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#include "llvm/Pass.h"
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#include "llvm/ADT/EquivalenceClasses.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Analysis/Dominators.h"
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@ -42,6 +41,8 @@
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#include <iostream>
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using namespace llvm;
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typedef DominatorTree::Node DTNodeType;
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namespace {
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Statistic<>
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NumVarsReplaced("predsimplify", "Number of argument substitutions");
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@ -52,40 +53,167 @@ namespace {
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Statistic<>
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NumBranches("predsimplify", "Number of branches made unconditional");
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/// Used for choosing the canonical Value in a synonym set.
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/// Leaves the better one in V1. Returns whether a swap took place.
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static void order(Value *&V1, Value *&V2) {
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/// Returns true if V1 is a better choice than V2. Note that it is
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/// not a total ordering.
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struct compare {
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bool operator()(Value *V1, Value *V2) const {
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if (isa<Constant>(V2)) {
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if (!isa<Constant>(V1)) {
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std::swap(V1, V2);
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return;
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return true;
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}
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} else if (isa<Argument>(V2)) {
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if (!isa<Constant>(V1) && !isa<Argument>(V1)) {
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std::swap(V1, V2);
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return;
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return true;
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}
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}
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if (User *U1 = dyn_cast<User>(V1)) {
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for (User::const_op_iterator I = U1->op_begin(), E = U1->op_end();
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I != E; ++I) {
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if (*I == V2) {
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return true;
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}
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}
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}
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return false;
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}
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};
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/// Used for choosing the canonical Value in a synonym set.
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/// Leaves the better one in V1.
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static void order(Value *&V1, Value *&V2) {
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static compare c;
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if (c(V1, V2))
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std::swap(V1, V2);
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return;
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}
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/// Similar to EquivalenceClasses, this stores the set of equivalent
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/// types. Beyond EquivalenceClasses, it allows the user to specify
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/// which element will act as leader through a StrictWeakOrdering
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/// function.
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template<typename ElemTy, typename StrictWeak>
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class VISIBILITY_HIDDEN Synonyms {
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std::map<ElemTy, unsigned> mapping;
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std::vector<ElemTy> leaders;
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StrictWeak swo;
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public:
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typedef unsigned iterator;
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typedef const unsigned const_iterator;
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// Inspection
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bool empty() const {
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return leaders.empty();
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}
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iterator findLeader(ElemTy e) {
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typename std::map<ElemTy, unsigned>::iterator MI = mapping.find(e);
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if (MI == mapping.end()) return 0;
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return MI->second;
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}
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const_iterator findLeader(ElemTy e) const {
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typename std::map<ElemTy, unsigned>::const_iterator MI =
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mapping.find(e);
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if (MI == mapping.end()) return 0;
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return MI->second;
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}
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ElemTy &getLeader(iterator I) {
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assert(I != 0 && "Element zero is out of range.");
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return leaders[I-1];
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}
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const ElemTy &getLeader(const_iterator I) const {
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assert(I != 0 && "Element zero is out of range.");
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return leaders[I-1];
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}
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#ifdef DEBUG
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void debug(std::ostream &os) const {
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for (unsigned i = 1, e = leaders.size()+1; i != e; ++i) {
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os << i << ". " << *leaders[i-1] << ": [";
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for (std::map<Value *, unsigned>::const_iterator
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I = mapping.begin(), E = mapping.end(); I != E; ++I) {
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if ((*I).second == i && (*I).first != leaders[i-1]) {
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os << *(*I).first << " ";
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}
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}
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os << "]\n";
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}
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return;
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}
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#endif
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// Mutators
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/// Combine two sets referring to the same element, inserting the
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/// elements as needed. Returns a valid iterator iff two already
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/// existing disjoint synonym sets were combined. The iterator
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/// points to the removed element.
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iterator unionSets(ElemTy E1, ElemTy E2) {
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if (swo(E1, E2)) std::swap(E1, E2);
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iterator I1 = findLeader(E1);
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iterator I2 = findLeader(E2);
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if (!I1 && !I2) { // neither entry is in yet
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leaders.push_back(E1);
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I1 = leaders.size();
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mapping[E1] = I1;
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mapping[E2] = I1;
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return false;
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}
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if (!I1 && I2) {
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mapping[E1] = I2;
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return false;
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}
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if (I1 && !I2) {
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mapping[E2] = I1;
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return false;
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}
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// This is the case where we have two sets, [%a1, %a2, %a3] and
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// [%p1, %p2, %p3] and someone says that %a2 == %p3. We need to
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// combine the two synsets.
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for (std::map<Value *, unsigned>::iterator I = mapping.begin(),
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E = mapping.end(); I != E; ++I) {
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if (I->second == I2) I->second = I1;
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else if (I->second > I2) --I->second;
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}
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leaders.erase(leaders.begin() + I2 - 1);
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return true;
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}
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/// Returns an iterator pointing to the synonym set containing
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/// element e. If none exists, a new one is created and returned.
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iterator findOrInsert(ElemTy e) {
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iterator I = findLeader(e);
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if (I) return I;
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leaders.push_back(e);
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I = leaders.size();
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mapping[e] = I;
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return I;
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}
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};
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/// Represents the set of equivalent Value*s and provides insertion
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/// and fast lookup. Also stores the set of inequality relationships.
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class PropertySet {
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struct Property;
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class EquivalenceClasses<Value *> union_find;
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public:
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class Synonyms<Value *, compare> union_find;
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typedef std::vector<Property>::iterator PropertyIterator;
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typedef std::vector<Property>::const_iterator ConstPropertyIterator;
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typedef Synonyms<Value *, compare>::iterator SynonymIterator;
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enum Ops {
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EQ,
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@ -98,10 +226,9 @@ namespace {
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}
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Value *lookup(Value *V) const {
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EquivalenceClasses<Value *>::member_iterator SI =
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union_find.findLeader(V);
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if (SI == union_find.member_end()) return NULL;
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return *SI;
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Synonyms<Value *, compare>::iterator SI = union_find.findLeader(V);
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if (!SI) return NULL;
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return union_find.getLeader(SI);
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}
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bool empty() const {
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@ -117,7 +244,18 @@ namespace {
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if (isa<Constant>(V2)) return; // refuse to set false == true.
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DEBUG(std::cerr << "equal: " << *V1 << " and " << *V2 << "\n");
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union_find.unionSets(V1, V2);
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SynonymIterator deleted = union_find.unionSets(V1, V2);
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if (deleted) {
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SynonymIterator replacement = union_find.findLeader(V1);
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// Move Properties
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for (PropertyIterator I = Properties.begin(), E = Properties.end();
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I != E; ++I) {
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if (I->I1 == deleted) I->I1 = replacement;
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else if (I->I1 > deleted) --I->I1;
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if (I->I2 == deleted) I->I2 = replacement;
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else if (I->I2 > deleted) --I->I2;
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}
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}
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addImpliedProperties(EQ, V1, V2);
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}
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@ -130,7 +268,9 @@ namespace {
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return; // found.
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// Add the property.
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Properties.push_back(Property(NE, V1, V2));
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SynonymIterator I1 = union_find.findOrInsert(V1),
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I2 = union_find.findOrInsert(V2);
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Properties.push_back(Property(NE, I1, I2));
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addImpliedProperties(NE, V1, V2);
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}
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@ -138,22 +278,12 @@ namespace {
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assert(Opcode != EQ && "Can't findProperty on EQ."
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"Use the lookup method instead.");
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V1 = canonicalize(V1);
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V2 = canonicalize(V2);
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SynonymIterator I1 = union_find.findLeader(V1),
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I2 = union_find.findLeader(V2);
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if (!I1 || !I2) return Properties.end();
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// Does the property already exist?
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for (PropertyIterator I = Properties.begin(), E = Properties.end();
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I != E; ++I) {
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if (I->Opcode != Opcode) continue;
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I->V1 = canonicalize(I->V1);
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I->V2 = canonicalize(I->V2);
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if ((I->V1 == V1 && I->V2 == V2) ||
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(I->V1 == V2 && I->V2 == V1)) {
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return I; // Found.
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}
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}
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return Properties.end();
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return
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find(Properties.begin(), Properties.end(), Property(Opcode, I1, I2));
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}
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ConstPropertyIterator
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@ -161,35 +291,33 @@ namespace {
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assert(Opcode != EQ && "Can't findProperty on EQ."
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"Use the lookup method instead.");
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V1 = canonicalize(V1);
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V2 = canonicalize(V2);
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SynonymIterator I1 = union_find.findLeader(V1),
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I2 = union_find.findLeader(V2);
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if (!I1 || !I2) return Properties.end();
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// Does the property already exist?
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for (ConstPropertyIterator I = Properties.begin(),
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E = Properties.end(); I != E; ++I) {
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if (I->Opcode != Opcode) continue;
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Value *v1 = canonicalize(I->V1),
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*v2 = canonicalize(I->V2);
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if ((v1 == V1 && v2 == V2) ||
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(v1 == V2 && v2 == V1)) {
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return I; // Found.
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}
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}
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return Properties.end();
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return
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find(Properties.begin(), Properties.end(), Property(Opcode, I1, I2));
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}
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private:
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// Represents Head OP [Tail1, Tail2, ...]
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// For example: %x != %a, %x != %b.
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struct Property {
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Property(Ops opcode, Value *v1, Value *v2)
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: Opcode(opcode), V1(v1), V2(v2)
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struct VISIBILITY_HIDDEN Property {
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typedef Synonyms<Value *, compare>::iterator Iter;
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Property(Ops opcode, Iter i1, Iter i2)
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: Opcode(opcode), I1(i1), I2(i2)
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{ assert(opcode != EQ && "Equality belongs in the synonym set, "
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"not a property."); }
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bool operator==(const Property &P) const {
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return (Opcode == P.Opcode) &&
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((I1 == P.I1 && I2 == P.I2) ||
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(I1 == P.I2 && I2 == P.I1));
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}
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Ops Opcode;
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Value *V1, *V2;
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Iter I1, I2;
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};
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void add(Ops Opcode, Value *V1, Value *V2, bool invert) {
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@ -207,7 +335,7 @@ namespace {
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}
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}
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// Finds the properties implied by a equivalence and adds them too.
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// Finds the properties implied by an equivalence and adds them too.
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// Example: ("seteq %a, %b", true, EQ) --> (%a, %b, EQ)
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// ("seteq %a, %b", false, EQ) --> (%a, %b, NE)
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void addImpliedProperties(Ops Opcode, Value *V1, Value *V2) {
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@ -286,14 +414,15 @@ namespace {
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public:
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#ifdef DEBUG
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void debug(std::ostream &os) const {
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for (EquivalenceClasses<Value*>::iterator I = union_find.begin(),
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E = union_find.end(); I != E; ++I) {
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if (!I->isLeader()) continue;
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for (EquivalenceClasses<Value*>::member_iterator MI =
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union_find.member_begin(I); MI != union_find.member_end(); ++MI)
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std::cerr << **MI << " ";
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std::cerr << "\n--\n";
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static const char *OpcodeTable[] = { "EQ", "NE" };
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union_find.debug(os);
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for (std::vector<Property>::const_iterator I = Properties.begin(),
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E = Properties.end(); I != E; ++I) {
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os << (*I).I1 << " " << OpcodeTable[(*I).Opcode] << " "
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<< (*I).I2 << "\n";
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}
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os << "\n";
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}
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#endif
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@ -319,22 +448,24 @@ namespace {
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// block to the next. Verifies that "current" dominates "next",
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// then calls visitBasicBlock.
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void proceedToSuccessor(PropertySet &CurrentPS, PropertySet &NextPS,
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DominatorTree::Node *Current, DominatorTree::Node *Next);
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DTNodeType *Current, DTNodeType *Next);
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void proceedToSuccessor(PropertySet &CurrentPS,
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DominatorTree::Node *Current, DominatorTree::Node *Next);
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DTNodeType *Current, DTNodeType *Next);
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// Visits each instruction in the basic block.
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void visitBasicBlock(DominatorTree::Node *DTNode,
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PropertySet &KnownProperties);
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void visitBasicBlock(DTNodeType *DTNode, PropertySet &KnownProperties);
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// Tries to simplify each Instruction and add new properties to
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// the PropertySet. Returns true if it erase the instruction.
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void visitInstruction(Instruction *I, DTNodeType *, PropertySet &);
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// For each instruction, add the properties to KnownProperties.
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void visit(Instruction *I, DominatorTree::Node *, PropertySet &);
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void visit(TerminatorInst *TI, DominatorTree::Node *, PropertySet &);
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void visit(BranchInst *BI, DominatorTree::Node *, PropertySet &);
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void visit(SwitchInst *SI, DominatorTree::Node *, PropertySet);
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void visit(LoadInst *LI, DominatorTree::Node *, PropertySet &);
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void visit(StoreInst *SI, DominatorTree::Node *, PropertySet &);
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void visit(BinaryOperator *BO, DominatorTree::Node *, PropertySet &);
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void visit(TerminatorInst *TI, DTNodeType *, PropertySet &);
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void visit(BranchInst *BI, DTNodeType *, PropertySet &);
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void visit(SwitchInst *SI, DTNodeType *, PropertySet);
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void visit(LoadInst *LI, DTNodeType *, PropertySet &);
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void visit(StoreInst *SI, DTNodeType *, PropertySet &);
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void visit(BinaryOperator *BO, DTNodeType *, PropertySet &);
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DominatorTree *DT;
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bool modified;
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@ -421,18 +552,11 @@ Value *PredicateSimplifier::resolve(BinaryOperator *BO,
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if (SetCondInst *SCI = dyn_cast<SetCondInst>(BO))
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return resolve(SCI, KP);
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DEBUG(std::cerr << "BO->getOperand(1) = " << *BO->getOperand(1) << "\n");
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Value *lhs = resolve(BO->getOperand(0), KP),
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*rhs = resolve(BO->getOperand(1), KP);
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ConstantIntegral *CI1 = dyn_cast<ConstantIntegral>(lhs);
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ConstantIntegral *CI2 = dyn_cast<ConstantIntegral>(rhs);
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DEBUG(std::cerr << "resolveBO: lhs = " << *lhs
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<< ", rhs = " << *rhs << "\n");
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if (CI1) DEBUG(std::cerr << "CI1 = " << *CI1);
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if (CI2) DEBUG(std::cerr << "CI2 = " << *CI2);
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if (!CI1 || !CI2) return BO;
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Value *V = ConstantExpr::get(BO->getOpcode(), CI1, CI2);
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@ -464,27 +588,28 @@ Value *PredicateSimplifier::resolve(Value *V, const PropertySet &KP) {
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return V;
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}
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void PredicateSimplifier::visitBasicBlock(DominatorTree::Node *DTNode,
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void PredicateSimplifier::visitBasicBlock(DTNodeType *DTNode,
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PropertySet &KnownProperties) {
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BasicBlock *BB = DTNode->getBlock();
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for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
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visit(I, DTNode, KnownProperties);
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visitInstruction(I, DTNode, KnownProperties);
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}
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}
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void PredicateSimplifier::visit(Instruction *I, DominatorTree::Node *DTNode,
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void PredicateSimplifier::visitInstruction(Instruction *I,
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DTNodeType *DTNode,
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PropertySet &KnownProperties) {
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DEBUG(std::cerr << "Considering instruction " << *I << "\n");
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DEBUG(KnownProperties.debug(std::cerr));
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// Try to replace whole instruction.
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// Try to replace the whole instruction.
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Value *V = resolve(I, KnownProperties);
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assert(V && "resolve not supposed to return NULL.");
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if (V != I) {
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modified = true;
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++NumInstruction;
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I->replaceAllUsesWith(V);
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I->eraseFromParent();
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return;
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}
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@ -513,8 +638,9 @@ void PredicateSimplifier::visit(Instruction *I, DominatorTree::Node *DTNode,
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}
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void PredicateSimplifier::proceedToSuccessor(PropertySet &CurrentPS,
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PropertySet &NextPS, DominatorTree::Node *Current,
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DominatorTree::Node *Next) {
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PropertySet &NextPS,
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DTNodeType *Current,
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DTNodeType *Next) {
|
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if (Next->getBlock()->getSinglePredecessor() == Current->getBlock())
|
||||
proceedToSuccessor(NextPS, Current, Next);
|
||||
else
|
||||
@ -522,13 +648,14 @@ void PredicateSimplifier::proceedToSuccessor(PropertySet &CurrentPS,
|
||||
}
|
||||
|
||||
void PredicateSimplifier::proceedToSuccessor(PropertySet &KP,
|
||||
DominatorTree::Node *Current, DominatorTree::Node *Next) {
|
||||
DTNodeType *Current,
|
||||
DTNodeType *Next) {
|
||||
if (Current->properlyDominates(Next))
|
||||
visitBasicBlock(Next, KP);
|
||||
}
|
||||
|
||||
void PredicateSimplifier::visit(TerminatorInst *TI,
|
||||
DominatorTree::Node *Node, PropertySet &KP){
|
||||
void PredicateSimplifier::visit(TerminatorInst *TI, DTNodeType *Node,
|
||||
PropertySet &KP) {
|
||||
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
|
||||
visit(BI, Node, KP);
|
||||
return;
|
||||
@ -545,8 +672,8 @@ void PredicateSimplifier::visit(TerminatorInst *TI,
|
||||
}
|
||||
}
|
||||
|
||||
void PredicateSimplifier::visit(BranchInst *BI,
|
||||
DominatorTree::Node *Node, PropertySet &KP){
|
||||
void PredicateSimplifier::visit(BranchInst *BI, DTNodeType *Node,
|
||||
PropertySet &KP) {
|
||||
if (BI->isUnconditional()) {
|
||||
proceedToSuccessor(KP, Node, DT->getNode(BI->getSuccessor(0)));
|
||||
return;
|
||||
@ -586,41 +713,44 @@ void PredicateSimplifier::visit(BranchInst *BI,
|
||||
proceedToSuccessor(KPcopy, FalseProperties, Node, DT->getNode(FalseDest));
|
||||
}
|
||||
|
||||
void PredicateSimplifier::visit(SwitchInst *SI,
|
||||
DominatorTree::Node *DTNode, PropertySet KP) {
|
||||
void PredicateSimplifier::visit(SwitchInst *SI, DTNodeType *DTNode,
|
||||
PropertySet KP) {
|
||||
Value *Condition = SI->getCondition();
|
||||
DEBUG(assert(Condition == KP.canonicalize(Condition) &&
|
||||
"Instruction wasn't already canonicalized?"));
|
||||
assert(Condition == KP.canonicalize(Condition) &&
|
||||
"Instruction wasn't already canonicalized?");
|
||||
|
||||
// If there's an NEProperty covering this SwitchInst, we may be able to
|
||||
// eliminate one of the cases.
|
||||
for (PropertySet::ConstPropertyIterator I = KP.Properties.begin(),
|
||||
E = KP.Properties.end(); I != E; ++I) {
|
||||
if (I->Opcode != PropertySet::NE) continue;
|
||||
Value *V1 = KP.canonicalize(I->V1),
|
||||
*V2 = KP.canonicalize(I->V2);
|
||||
if (V1 != Condition && V2 != Condition) continue;
|
||||
Value *V1 = KP.union_find.getLeader(I->I1),
|
||||
*V2 = KP.union_find.getLeader(I->I2);
|
||||
|
||||
// Is one side a number?
|
||||
ConstantInt *CI = dyn_cast<ConstantInt>(KP.canonicalize(I->V1));
|
||||
if (!CI) CI = dyn_cast<ConstantInt>(KP.canonicalize(I->V2));
|
||||
// Find a Property with a ConstantInt on one side and our
|
||||
// Condition on the other.
|
||||
ConstantInt *CI = NULL;
|
||||
if (V1 == Condition)
|
||||
CI = dyn_cast<ConstantInt>(V2);
|
||||
else if (V2 == Condition)
|
||||
CI = dyn_cast<ConstantInt>(V1);
|
||||
|
||||
if (!CI) continue;
|
||||
|
||||
if (CI) {
|
||||
unsigned i = SI->findCaseValue(CI);
|
||||
if (i != 0) {
|
||||
if (i != 0) { // zero is reserved for the default case.
|
||||
SI->getSuccessor(i)->removePredecessor(SI->getParent());
|
||||
SI->removeCase(i);
|
||||
modified = true;
|
||||
++NumSwitchCases;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Set the EQProperty in each of the cases BBs,
|
||||
// and the NEProperties in the default BB.
|
||||
PropertySet DefaultProperties(KP);
|
||||
|
||||
DominatorTree::Node *Node = DT->getNode(SI->getParent()),
|
||||
DTNodeType *Node = DT->getNode(SI->getParent()),
|
||||
*DefaultNode = DT->getNode(SI->getSuccessor(0));
|
||||
if (!Node->dominates(DefaultNode)) DefaultNode = NULL;
|
||||
|
||||
@ -644,20 +774,20 @@ void PredicateSimplifier::visit(SwitchInst *SI,
|
||||
proceedToSuccessor(DefaultProperties, DTNode, DefaultNode);
|
||||
}
|
||||
|
||||
void PredicateSimplifier::visit(LoadInst *LI,
|
||||
DominatorTree::Node *, PropertySet &KP) {
|
||||
void PredicateSimplifier::visit(LoadInst *LI, DTNodeType *,
|
||||
PropertySet &KP) {
|
||||
Value *Ptr = LI->getPointerOperand();
|
||||
KP.addNotEqual(Constant::getNullValue(Ptr->getType()), Ptr);
|
||||
}
|
||||
|
||||
void PredicateSimplifier::visit(StoreInst *SI,
|
||||
DominatorTree::Node *, PropertySet &KP) {
|
||||
void PredicateSimplifier::visit(StoreInst *SI, DTNodeType *,
|
||||
PropertySet &KP) {
|
||||
Value *Ptr = SI->getPointerOperand();
|
||||
KP.addNotEqual(Constant::getNullValue(Ptr->getType()), Ptr);
|
||||
}
|
||||
|
||||
void PredicateSimplifier::visit(BinaryOperator *BO,
|
||||
DominatorTree::Node *, PropertySet &KP) {
|
||||
void PredicateSimplifier::visit(BinaryOperator *BO, DTNodeType *,
|
||||
PropertySet &KP) {
|
||||
Instruction::BinaryOps ops = BO->getOpcode();
|
||||
|
||||
switch (ops) {
|
||||
@ -670,8 +800,4 @@ void PredicateSimplifier::visit(BinaryOperator *BO,
|
||||
default:
|
||||
break;
|
||||
}
|
||||
|
||||
// Some other things we could do:
|
||||
// In f=x*y, if x != 1 && y != 1 then f != x && f != y.
|
||||
// In f=x+y, if x != 0 then f != y and if y != 0 then f != x.
|
||||
}
|
||||
|
||||
@ -0,0 +1,28 @@
|
||||
; RUN: llvm-as < %s | opt -predsimplify -disable-output
|
||||
|
||||
void %safe_strcpy(uint %size1) {
|
||||
entry:
|
||||
%tmp = seteq uint %size1, 0 ; <bool> [#uses=1]
|
||||
br bool %tmp, label %return, label %strlen.exit
|
||||
|
||||
strlen.exit: ; preds = %entry
|
||||
%tmp = cast ulong 0 to uint ; <uint> [#uses=2]
|
||||
%tmp6 = setlt uint %tmp, %size1 ; <bool> [#uses=1]
|
||||
br bool %tmp6, label %cond_true7, label %cond_false19
|
||||
|
||||
cond_true7: ; preds = %strlen.exit
|
||||
%tmp9 = seteq uint %tmp, 0 ; <bool> [#uses=1]
|
||||
br bool %tmp9, label %cond_next15, label %cond_true10
|
||||
|
||||
cond_true10: ; preds = %cond_true7
|
||||
ret void
|
||||
|
||||
cond_next15: ; preds = %cond_true7
|
||||
ret void
|
||||
|
||||
cond_false19: ; preds = %strlen.exit
|
||||
ret void
|
||||
|
||||
return: ; preds = %entry
|
||||
ret void
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user