mirror of
https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30305 91177308-0d34-0410-b5e6-96231b3b80d8
838 lines
27 KiB
C++
838 lines
27 KiB
C++
//===-- PredicateSimplifier.cpp - Path Sensitive Simplifier -----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Nick Lewycky and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===------------------------------------------------------------------===//
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//
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// Path-sensitive optimizer. In a branch where x == y, replace uses of
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// x with y. Permits further optimization, such as the elimination of
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// the unreachable call:
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//
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// void test(int *p, int *q)
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// {
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// if (p != q)
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// return;
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//
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// if (*p != *q)
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// foo(); // unreachable
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// }
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//
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//===------------------------------------------------------------------===//
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//
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// This optimization works by substituting %q for %p when protected by a
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// conditional that assures us of that fact. Properties are stored as
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// relationships between two values.
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//
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//===------------------------------------------------------------------===//
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#define DEBUG_TYPE "predsimplify"
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#include "llvm/Transforms/Scalar.h"
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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/Statistic.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/Debug.h"
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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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Statistic<>
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NumInstruction("predsimplify", "Number of instructions removed");
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Statistic<>
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NumSwitchCases("predsimplify", "Number of switch cases removed");
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Statistic<>
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NumBranches("predsimplify", "Number of branches made unconditional");
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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>(V1)) {
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if (!isa<Constant>(V2)) {
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return true;
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}
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} else if (isa<Argument>(V1)) {
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if (!isa<Constant>(V2) && !isa<Argument>(V2)) {
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return true;
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}
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}
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if (User *U = dyn_cast<User>(V2)) {
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for (User::const_op_iterator I = U->op_begin(), E = U->op_end();
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I != E; ++I) {
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if (*I == V1) {
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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 choice 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(V2, V1))
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std::swap(V1, V2);
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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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unsigned countLeaders() const {
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return leaders.size();
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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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assert(I <= leaders.size() && "Invalid iterator.");
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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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std::set<Value *> Unique;
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for (unsigned i = 1, e = leaders.size()+1; i != e; ++i) {
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Unique.insert(getLeader(i));
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os << i << ". " << *getLeader(i) << ": [";
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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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assert(Unique.size() == leaders.size() && "Duplicate leaders.");
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for (typename std::map<ElemTy, unsigned>::const_iterator
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I = mapping.begin(), E = mapping.end(); I != E; ++I) {
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assert(I->second != 0 && "Zero iterator in mapping.");
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assert(I->second <= leaders.size() &&
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"Invalid iterator found in mapping.");
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}
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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(E2, E1)) std::swap(E1, E2);
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iterator I1 = findLeader(E1),
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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 0;
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}
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if (!I1 && I2) {
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mapping[E1] = I2;
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std::swap(getLeader(I2), E1);
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return 0;
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}
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if (I1 && !I2) {
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mapping[E2] = I1;
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return 0;
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}
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if (I1 == I2) return 0;
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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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if (I1 > I2) --I1;
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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 I2;
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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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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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NE
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};
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Value *canonicalize(Value *V) const {
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Value *C = lookup(V);
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return C ? C : V;
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}
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Value *lookup(Value *V) const {
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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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return union_find.empty();
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}
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void addEqual(Value *V1, Value *V2) {
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// If %x = 0. and %y = -0., seteq %x, %y is true, but
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// copysign(%x) is not the same as copysign(%y).
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if (V1->getType()->isFloatingPoint()) return;
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order(V1, V2);
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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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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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void addNotEqual(Value *V1, Value *V2) {
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// If %x = NAN then seteq %x, %x is false.
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if (V1->getType()->isFloatingPoint()) return;
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// For example, %x = setne int 0, 0 causes "0 != 0".
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if (isa<Constant>(V1) && isa<Constant>(V2)) return;
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DEBUG(std::cerr << "not equal: " << *V1 << " and " << *V2 << "\n");
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if (findProperty(NE, V1, V2) != Properties.end())
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return; // found.
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// Add the property.
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SynonymIterator I1 = union_find.findOrInsert(V1),
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I2 = union_find.findOrInsert(V2);
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// Technically this means that the block is unreachable.
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if (I1 == I2) return;
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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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PropertyIterator findProperty(Ops Opcode, Value *V1, Value *V2) {
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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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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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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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findProperty(Ops Opcode, Value *V1, Value *V2) const {
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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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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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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 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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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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switch (Opcode) {
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case EQ:
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if (invert) addNotEqual(V1, V2);
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else addEqual(V1, V2);
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break;
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case NE:
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if (invert) addEqual(V1, V2);
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else addNotEqual(V1, V2);
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break;
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default:
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assert(0 && "Unknown property opcode.");
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}
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}
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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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order(V1, V2);
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if (BinaryOperator *BO = dyn_cast<BinaryOperator>(V2)) {
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switch (BO->getOpcode()) {
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case Instruction::SetEQ:
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if (V1 == ConstantBool::True)
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add(Opcode, BO->getOperand(0), BO->getOperand(1), false);
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if (V1 == ConstantBool::False)
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add(Opcode, BO->getOperand(0), BO->getOperand(1), true);
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break;
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case Instruction::SetNE:
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if (V1 == ConstantBool::True)
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add(Opcode, BO->getOperand(0), BO->getOperand(1), true);
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if (V1 == ConstantBool::False)
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add(Opcode, BO->getOperand(0), BO->getOperand(1), false);
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break;
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case Instruction::SetLT:
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case Instruction::SetGT:
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if (V1 == ConstantBool::True)
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add(Opcode, BO->getOperand(0), BO->getOperand(1), true);
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break;
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case Instruction::SetLE:
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case Instruction::SetGE:
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if (V1 == ConstantBool::False)
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add(Opcode, BO->getOperand(0), BO->getOperand(1), true);
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break;
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case Instruction::And:
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if (V1 == ConstantBool::True) {
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add(Opcode, ConstantBool::True, BO->getOperand(0), false);
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add(Opcode, ConstantBool::True, BO->getOperand(1), false);
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}
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break;
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case Instruction::Or:
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if (V1 == ConstantBool::False) {
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add(Opcode, ConstantBool::False, BO->getOperand(0), false);
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add(Opcode, ConstantBool::False, BO->getOperand(1), false);
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}
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break;
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case Instruction::Xor:
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if (V1 == ConstantBool::True) {
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if (BO->getOperand(0) == ConstantBool::True)
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add(Opcode, ConstantBool::False, BO->getOperand(1), false);
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if (BO->getOperand(1) == ConstantBool::True)
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add(Opcode, ConstantBool::False, BO->getOperand(0), false);
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}
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if (V1 == ConstantBool::False) {
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if (BO->getOperand(0) == ConstantBool::True)
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add(Opcode, ConstantBool::True, BO->getOperand(1), false);
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if (BO->getOperand(1) == ConstantBool::True)
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add(Opcode, ConstantBool::True, BO->getOperand(0), false);
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}
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break;
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default:
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break;
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}
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} else if (SelectInst *SI = dyn_cast<SelectInst>(V2)) {
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if (Opcode != EQ && Opcode != NE) return;
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ConstantBool *True = (Opcode==EQ) ? ConstantBool::True
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: ConstantBool::False,
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*False = (Opcode==EQ) ? ConstantBool::False
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: ConstantBool::True;
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if (V1 == SI->getTrueValue())
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addEqual(SI->getCondition(), True);
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else if (V1 == SI->getFalseValue())
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addEqual(SI->getCondition(), False);
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else if (Opcode == EQ)
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assert("Result of select not equal to either value.");
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}
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}
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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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static const char *OpcodeTable[] = { "EQ", "NE" };
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unsigned int size = union_find.countLeaders();
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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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assert((*I).I1 <= size && "Invalid property.");
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assert((*I).I2 <= size && "Invalid property.");
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}
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os << "\n";
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}
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#endif
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std::vector<Property> Properties;
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};
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/// PredicateSimplifier - This class is a simplifier that replaces
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/// one equivalent variable with another. It also tracks what
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/// can't be equal and will solve setcc instructions when possible.
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class PredicateSimplifier : public FunctionPass {
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public:
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bool runOnFunction(Function &F);
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virtual void getAnalysisUsage(AnalysisUsage &AU) const;
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private:
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// Try to replace the Use of the instruction with something simpler.
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Value *resolve(SetCondInst *SCI, const PropertySet &);
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Value *resolve(BinaryOperator *BO, const PropertySet &);
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Value *resolve(SelectInst *SI, const PropertySet &);
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Value *resolve(Value *V, const PropertySet &);
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// Used by terminator instructions to proceed from the current basic
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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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DTNodeType *Current, DTNodeType *Next);
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void proceedToSuccessor(PropertySet &CurrentPS,
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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(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(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 &);
|
|
|
|
DominatorTree *DT;
|
|
bool modified;
|
|
};
|
|
|
|
RegisterPass<PredicateSimplifier> X("predsimplify",
|
|
"Predicate Simplifier");
|
|
}
|
|
|
|
FunctionPass *llvm::createPredicateSimplifierPass() {
|
|
return new PredicateSimplifier();
|
|
}
|
|
|
|
bool PredicateSimplifier::runOnFunction(Function &F) {
|
|
DT = &getAnalysis<DominatorTree>();
|
|
|
|
modified = false;
|
|
PropertySet KnownProperties;
|
|
visitBasicBlock(DT->getRootNode(), KnownProperties);
|
|
return modified;
|
|
}
|
|
|
|
void PredicateSimplifier::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.addRequired<DominatorTree>();
|
|
}
|
|
|
|
// resolve catches cases addProperty won't because it wasn't used as a
|
|
// condition in the branch, and that visit won't, because the instruction
|
|
// was defined outside of the scope that the properties apply to.
|
|
Value *PredicateSimplifier::resolve(SetCondInst *SCI,
|
|
const PropertySet &KP) {
|
|
// Attempt to resolve the SetCondInst to a boolean.
|
|
|
|
Value *SCI0 = resolve(SCI->getOperand(0), KP),
|
|
*SCI1 = resolve(SCI->getOperand(1), KP);
|
|
|
|
ConstantIntegral *CI1 = dyn_cast<ConstantIntegral>(SCI0),
|
|
*CI2 = dyn_cast<ConstantIntegral>(SCI1);
|
|
|
|
if (!CI1 || !CI2) {
|
|
PropertySet::ConstPropertyIterator NE =
|
|
KP.findProperty(PropertySet::NE, SCI0, SCI1);
|
|
|
|
if (NE != KP.Properties.end()) {
|
|
switch (SCI->getOpcode()) {
|
|
case Instruction::SetEQ:
|
|
return ConstantBool::False;
|
|
case Instruction::SetNE:
|
|
return ConstantBool::True;
|
|
case Instruction::SetLE:
|
|
case Instruction::SetGE:
|
|
case Instruction::SetLT:
|
|
case Instruction::SetGT:
|
|
break;
|
|
default:
|
|
assert(0 && "Unknown opcode in SetCondInst.");
|
|
break;
|
|
}
|
|
}
|
|
return SCI;
|
|
}
|
|
|
|
switch(SCI->getOpcode()) {
|
|
case Instruction::SetLE:
|
|
case Instruction::SetGE:
|
|
case Instruction::SetEQ:
|
|
if (CI1->getRawValue() == CI2->getRawValue())
|
|
return ConstantBool::True;
|
|
else
|
|
return ConstantBool::False;
|
|
case Instruction::SetLT:
|
|
case Instruction::SetGT:
|
|
case Instruction::SetNE:
|
|
if (CI1->getRawValue() == CI2->getRawValue())
|
|
return ConstantBool::False;
|
|
else
|
|
return ConstantBool::True;
|
|
default:
|
|
assert(0 && "Unknown opcode in SetContInst.");
|
|
break;
|
|
}
|
|
}
|
|
|
|
Value *PredicateSimplifier::resolve(BinaryOperator *BO,
|
|
const PropertySet &KP) {
|
|
if (SetCondInst *SCI = dyn_cast<SetCondInst>(BO))
|
|
return resolve(SCI, KP);
|
|
|
|
Value *lhs = resolve(BO->getOperand(0), KP),
|
|
*rhs = resolve(BO->getOperand(1), KP);
|
|
ConstantIntegral *CI1 = dyn_cast<ConstantIntegral>(lhs);
|
|
ConstantIntegral *CI2 = dyn_cast<ConstantIntegral>(rhs);
|
|
|
|
if (!CI1 || !CI2) return BO;
|
|
|
|
Value *V = ConstantExpr::get(BO->getOpcode(), CI1, CI2);
|
|
if (V) return V;
|
|
return BO;
|
|
}
|
|
|
|
Value *PredicateSimplifier::resolve(SelectInst *SI, const PropertySet &KP) {
|
|
Value *Condition = resolve(SI->getCondition(), KP);
|
|
if (Condition == ConstantBool::True)
|
|
return resolve(SI->getTrueValue(), KP);
|
|
else if (Condition == ConstantBool::False)
|
|
return resolve(SI->getFalseValue(), KP);
|
|
return SI;
|
|
}
|
|
|
|
Value *PredicateSimplifier::resolve(Value *V, const PropertySet &KP) {
|
|
if (isa<Constant>(V) || isa<BasicBlock>(V) || KP.empty()) return V;
|
|
|
|
V = KP.canonicalize(V);
|
|
|
|
DEBUG(std::cerr << "peering into " << *V << "\n");
|
|
|
|
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(V))
|
|
return resolve(BO, KP);
|
|
else if (SelectInst *SI = dyn_cast<SelectInst>(V))
|
|
return resolve(SI, KP);
|
|
|
|
return V;
|
|
}
|
|
|
|
void PredicateSimplifier::visitBasicBlock(DTNodeType *DTNode,
|
|
PropertySet &KnownProperties) {
|
|
BasicBlock *BB = DTNode->getBlock();
|
|
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) {
|
|
visitInstruction(I++, DTNode, KnownProperties);
|
|
}
|
|
}
|
|
|
|
void PredicateSimplifier::visitInstruction(Instruction *I,
|
|
DTNodeType *DTNode,
|
|
PropertySet &KnownProperties) {
|
|
|
|
DEBUG(std::cerr << "Considering instruction " << *I << "\n");
|
|
DEBUG(KnownProperties.debug(std::cerr));
|
|
|
|
// Try to replace the whole instruction.
|
|
Value *V = resolve(I, KnownProperties);
|
|
assert(V->getType() == I->getType() && "Instruction type mutated!");
|
|
if (V != I) {
|
|
modified = true;
|
|
++NumInstruction;
|
|
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 = resolve(Oper, KnownProperties);
|
|
assert(V->getType() == Oper->getType() && "Operand type mutated!");
|
|
if (V != Oper) {
|
|
modified = true;
|
|
++NumVarsReplaced;
|
|
DEBUG(std::cerr << "resolving " << *I);
|
|
I->setOperand(i, V);
|
|
DEBUG(std::cerr << "into " << *I);
|
|
}
|
|
}
|
|
|
|
if (TerminatorInst *TI = dyn_cast<TerminatorInst>(I))
|
|
visit(TI, DTNode, KnownProperties);
|
|
else if (LoadInst *LI = dyn_cast<LoadInst>(I))
|
|
visit(LI, DTNode, KnownProperties);
|
|
else if (StoreInst *SI = dyn_cast<StoreInst>(I))
|
|
visit(SI, DTNode, KnownProperties);
|
|
else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I))
|
|
visit(BO, DTNode, KnownProperties);
|
|
}
|
|
|
|
void PredicateSimplifier::proceedToSuccessor(PropertySet &CurrentPS,
|
|
PropertySet &NextPS,
|
|
DTNodeType *Current,
|
|
DTNodeType *Next) {
|
|
if (Next->getBlock()->getSinglePredecessor() == Current->getBlock())
|
|
proceedToSuccessor(NextPS, Current, Next);
|
|
else
|
|
proceedToSuccessor(CurrentPS, Current, Next);
|
|
}
|
|
|
|
void PredicateSimplifier::proceedToSuccessor(PropertySet &KP,
|
|
DTNodeType *Current,
|
|
DTNodeType *Next) {
|
|
if (Current->properlyDominates(Next))
|
|
visitBasicBlock(Next, KP);
|
|
}
|
|
|
|
void PredicateSimplifier::visit(TerminatorInst *TI, DTNodeType *Node,
|
|
PropertySet &KP) {
|
|
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
|
|
visit(BI, Node, KP);
|
|
return;
|
|
}
|
|
if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
|
|
visit(SI, Node, KP);
|
|
return;
|
|
}
|
|
|
|
for (unsigned i = 0, E = TI->getNumSuccessors(); i != E; ++i) {
|
|
BasicBlock *BB = TI->getSuccessor(i);
|
|
PropertySet KPcopy(KP);
|
|
proceedToSuccessor(KPcopy, Node, DT->getNode(TI->getSuccessor(i)));
|
|
}
|
|
}
|
|
|
|
void PredicateSimplifier::visit(BranchInst *BI, DTNodeType *Node,
|
|
PropertySet &KP) {
|
|
if (BI->isUnconditional()) {
|
|
proceedToSuccessor(KP, Node, DT->getNode(BI->getSuccessor(0)));
|
|
return;
|
|
}
|
|
|
|
Value *Condition = BI->getCondition();
|
|
|
|
BasicBlock *TrueDest = BI->getSuccessor(0),
|
|
*FalseDest = BI->getSuccessor(1);
|
|
|
|
if (Condition == ConstantBool::True) {
|
|
FalseDest->removePredecessor(BI->getParent());
|
|
BI->setUnconditionalDest(TrueDest);
|
|
modified = true;
|
|
++NumBranches;
|
|
proceedToSuccessor(KP, Node, DT->getNode(TrueDest));
|
|
return;
|
|
} else if (Condition == ConstantBool::False) {
|
|
TrueDest->removePredecessor(BI->getParent());
|
|
BI->setUnconditionalDest(FalseDest);
|
|
modified = true;
|
|
++NumBranches;
|
|
proceedToSuccessor(KP, Node, DT->getNode(FalseDest));
|
|
return;
|
|
}
|
|
|
|
PropertySet TrueProperties(KP), FalseProperties(KP);
|
|
DEBUG(std::cerr << "true set:\n");
|
|
TrueProperties.addEqual(ConstantBool::True, Condition);
|
|
DEBUG(TrueProperties.debug(std::cerr));
|
|
DEBUG(std::cerr << "false set:\n");
|
|
FalseProperties.addEqual(ConstantBool::False, Condition);
|
|
DEBUG(FalseProperties.debug(std::cerr));
|
|
|
|
PropertySet KPcopy(KP);
|
|
proceedToSuccessor(KP, TrueProperties, Node, DT->getNode(TrueDest));
|
|
proceedToSuccessor(KPcopy, FalseProperties, Node, DT->getNode(FalseDest));
|
|
}
|
|
|
|
void PredicateSimplifier::visit(SwitchInst *SI, DTNodeType *DTNode,
|
|
PropertySet KP) {
|
|
Value *Condition = SI->getCondition();
|
|
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.union_find.getLeader(I->I1),
|
|
*V2 = KP.union_find.getLeader(I->I2);
|
|
|
|
// 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;
|
|
|
|
unsigned i = SI->findCaseValue(CI);
|
|
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);
|
|
|
|
DTNodeType *Node = DT->getNode(SI->getParent()),
|
|
*DefaultNode = DT->getNode(SI->getSuccessor(0));
|
|
if (!Node->dominates(DefaultNode)) DefaultNode = NULL;
|
|
|
|
for (unsigned I = 1, E = SI->getNumCases(); I < E; ++I) {
|
|
ConstantInt *CI = SI->getCaseValue(I);
|
|
|
|
BasicBlock *SuccBB = SI->getSuccessor(I);
|
|
PropertySet copy(KP);
|
|
if (SuccBB->getSinglePredecessor()) {
|
|
PropertySet NewProperties(KP);
|
|
NewProperties.addEqual(Condition, CI);
|
|
proceedToSuccessor(copy, NewProperties, DTNode, DT->getNode(SuccBB));
|
|
} else
|
|
proceedToSuccessor(copy, DTNode, DT->getNode(SuccBB));
|
|
|
|
if (DefaultNode)
|
|
DefaultProperties.addNotEqual(Condition, CI);
|
|
}
|
|
|
|
if (DefaultNode)
|
|
proceedToSuccessor(DefaultProperties, DTNode, DefaultNode);
|
|
}
|
|
|
|
void PredicateSimplifier::visit(LoadInst *LI, DTNodeType *,
|
|
PropertySet &KP) {
|
|
Value *Ptr = LI->getPointerOperand();
|
|
KP.addNotEqual(Constant::getNullValue(Ptr->getType()), Ptr);
|
|
}
|
|
|
|
void PredicateSimplifier::visit(StoreInst *SI, DTNodeType *,
|
|
PropertySet &KP) {
|
|
Value *Ptr = SI->getPointerOperand();
|
|
KP.addNotEqual(Constant::getNullValue(Ptr->getType()), Ptr);
|
|
}
|
|
|
|
void PredicateSimplifier::visit(BinaryOperator *BO, DTNodeType *,
|
|
PropertySet &KP) {
|
|
Instruction::BinaryOps ops = BO->getOpcode();
|
|
|
|
switch (ops) {
|
|
case Instruction::Div:
|
|
case Instruction::Rem: {
|
|
Value *Divisor = BO->getOperand(1);
|
|
KP.addNotEqual(Constant::getNullValue(Divisor->getType()), Divisor);
|
|
break;
|
|
}
|
|
default:
|
|
break;
|
|
}
|
|
}
|