bool visitICmpInst(ICmpInst& inst) {
// errs() << "got icmp instruction! " << inst << '\n';
bool changed = false;
if (inst.getPredicate() == CmpInst::ICMP_EQ) {
assert(inst.getNumOperands() == 2);
if (inst.getOperand(1) == processing) {
inst.swapOperands();
changed = true;
any_changes = true;
}
assert(dyn_cast<Instruction>(inst.getOperand(0)) == processing);
Value* other = inst.getOperand(1);
if (isa<ConstantPointerNull>(other)) {
if (VERBOSITY("opt") >= 2) {
errs() << inst << '\n';
errs() << "replacing with false!\n";
}
Value* new_value = ConstantInt::getFalse(other->getContext());
inst.replaceAllUsesWith(new_value);
inst.eraseFromParent();
changed = true;
any_changes = true;
}
}
return changed;
}
void RAFlowFunction::visitBranchInst(BranchInst &BI){
RALatticePoint* inRLP = new RALatticePoint(*(info_in_casted.back()));
info_in_casted.pop_back();
if (BI.isUnconditional()) {
for (std::map<Value *, LatticePoint *>::iterator it=out_map.begin(); it != out_map.end(); ++it){
Value* elm = it->first;
out_map[elm] = new RALatticePoint(*inRLP);
}
}
else{
Value* cond = BI.getCondition();
if (isa<ICmpInst>(cond)) {
// may affect elements of our lattice.
std::pair<Use*, Use *> branches = helper::getBranches(BI);
Use* true_branch = branches.first;
Use* false_branch = branches.second;
/*
errs() << "Examining instruction" << BI << "\n";
errs() << "True branch is " << * (true_branch->get()) << "\n";
errs() << "False branch is " << * (false_branch->get()) << "\n";
*/
ICmpInst* cmp = cast<ICmpInst>(cond);
std::pair<Use*, Use *> operands = helper::getOperands(*cmp);
Use* right_hand_side = operands.second;
Use* left_hand_side = operands.first;
/*
errs() << "Comparison " << *cmp << "\n";
errs() << "Left hand side is " << * (left_hand_side->get()) << "\n";
errs() << "Right hand side is " << * (right_hand_side->get()) << "\n";
*/
ConstantRange* lhs_range;
ConstantRange* rhs_range;
if (inRLP->representation.count(left_hand_side->get()) > 0) {
lhs_range = inRLP->representation[left_hand_side->get()];
}
else if (isa<ConstantInt>(left_hand_side->get())) {
ConstantInt* C2 = cast<ConstantInt>(left_hand_side->get());
lhs_range = new ConstantRange(C2->getValue());
}
else{
lhs_range = new ConstantRange(32, false);
}
if (inRLP->representation.count(right_hand_side->get()) > 0) {
rhs_range = inRLP->representation[right_hand_side->get()];
}
else if (isa<ConstantInt>(right_hand_side->get())) {
ConstantInt* C2 = cast<ConstantInt>(right_hand_side->get());
rhs_range = new ConstantRange(C2->getValue());
}
else{
rhs_range = new ConstantRange(32, false);
}
/*
errs() << "Left hand side has range ";
lhs_range->print(errs());
errs() << "\nRight hand side has range ";
rhs_range->print(errs());
errs() << " \n ";
*/
// First we compute the restrictions that cmp makes upon the regions.
//errs() << " Compare looks like " << *cmp << "\n";
int predicate = 0;
if (cmp->isSigned()) {
predicate = cmp->getSignedPredicate();
}
else{
predicate = cmp->getUnsignedPredicate();
}
ConstantRange true_branch_lhs_restriction = ConstantRange::makeICmpRegion(predicate, *rhs_range);
/*
errs() << "True branch lhs_restriction: ";
true_branch_lhs_restriction.print(errs());
errs() << "\n";
*/
ConstantRange false_branch_lhs_restriction = (ConstantRange(32, true)).difference(true_branch_lhs_restriction);
/*
errs() << "False branch lhs_restriction: ";
false_branch_lhs_restriction.print(errs());
errs() << "\n";
*/
cmp->swapOperands();
//errs() << " After swapping, compare looks like " << *cmp << "\n";
ConstantRange true_branch_rhs_restriction = ConstantRange::makeICmpRegion(predicate,*lhs_range);
/*
errs() << "\nTrue branch rhs_restriction: ";
true_branch_rhs_restriction.print(errs());
errs() << " is it wrapped range? " << true_branch_rhs_restriction.isSignWrappedSet() << " is it empty? " << true_branch_rhs_restriction.isEmptySet() << " what is its size? " << true_branch_rhs_restriction.getSetSize() << "\n";
*/
ConstantRange false_branch_rhs_restriction = (ConstantRange(32, true)).difference(true_branch_rhs_restriction);
/*
errs() << "False branch rhs_restriction: ";
false_branch_rhs_restriction.print(errs());
errs() << "\n";
*/
cmp->swapOperands();
// Next we intersect the ranges with the resulting restrictions.
ConstantRange* true_branch_lhs_range = new ConstantRange(lhs_range->getBitWidth(), true);
ConstantRange* false_branch_lhs_range = new ConstantRange(lhs_range->getBitWidth(), true);
ConstantRange* true_branch_rhs_range = new ConstantRange(rhs_range->getBitWidth(), true);
ConstantRange* false_branch_rhs_range = new ConstantRange(rhs_range->getBitWidth(), true);
*true_branch_lhs_range = lhs_range->intersectWith(true_branch_lhs_restriction);
*false_branch_lhs_range = lhs_range->intersectWith(false_branch_lhs_restriction);
*true_branch_rhs_range = rhs_range->intersectWith(true_branch_rhs_restriction);
*false_branch_rhs_range = rhs_range->intersectWith(false_branch_rhs_restriction);
/*
errs() << "True branch lhs range ";
true_branch_lhs_range->print(errs());
errs() << "\n";
errs() << "False branch lhs range ";
false_branch_lhs_range->print(errs());
errs() << "\n";
errs() << "True branch rhs range ";
true_branch_rhs_range->print(errs());
errs() << "\n";
errs() << "False branch rhs range ";
false_branch_rhs_range->print(errs());
errs() << "\n";
*/
RALatticePoint* true_branchRLP = new RALatticePoint(*inRLP);
RALatticePoint* false_branchRLP = new RALatticePoint(*inRLP);
true_branchRLP->isBottom = false;
true_branchRLP->isTop = false;
false_branchRLP->isBottom = false;
false_branchRLP->isTop = false;
if (inRLP->representation.count(left_hand_side->get()) > 0){
//errs() << "\nIn if statement for lhs \n";
true_branchRLP->representation[left_hand_side->get()] = true_branch_lhs_range;
false_branchRLP->representation[left_hand_side->get()] = false_branch_lhs_range;
/*
errs() << "True branch lhs range ";
true_branch_lhs_range->print(errs());
errs() << "\n";
errs() << "False branch lhs range ";
false_branch_lhs_range->print(errs());
errs() << "\n";
*/
}
if (inRLP->representation.count(right_hand_side->get()) > 0){
//errs() << "\nIn if statement for rhs \n";
true_branchRLP->representation[right_hand_side->get()] = true_branch_rhs_range;
false_branchRLP->representation[right_hand_side->get()] = false_branch_rhs_range;
/*
errs() << "True branch rhs range ";
true_branch_rhs_range->print(errs());
errs() << "\n";
errs() << "False branch rhs range ";
false_branch_rhs_range->print(errs());
errs() << "\n";
*/
}
/*
info_out.push_back(true_branchRLP);
info_out.push_back(false_branchRLP);
*/
out_map[true_branch->get()] = true_branchRLP;
/*
errs() << "\nTrue branch lattice point is ";
true_branchRLP->printToErrs();
*/
out_map[false_branch->get()] = false_branchRLP;
/*
errs() << "\nFalse branch lattice point is ";
false_branchRLP->printToErrs();
*/
}
else{
// does not affect our lattice.
for (std::map<Value *, LatticePoint *>::iterator it=out_map.begin(); it != out_map.end(); ++it){
Value* elm = it->first;
out_map[elm] = new RALatticePoint(*inRLP);
}
}
}
}
