bool CallAnalyzer::visitICmp(ICmpInst &I) {
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
// First try to handle simplified comparisons.
if (!isa<Constant>(LHS))
if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
LHS = SimpleLHS;
if (!isa<Constant>(RHS))
if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
RHS = SimpleRHS;
if (Constant *CLHS = dyn_cast<Constant>(LHS))
if (Constant *CRHS = dyn_cast<Constant>(RHS))
if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) {
SimplifiedValues[&I] = C;
return true;
}
// Otherwise look for a comparison between constant offset pointers with
// a common base.
Value *LHSBase, *RHSBase;
APInt LHSOffset, RHSOffset;
llvm::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS);
if (LHSBase) {
llvm::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS);
if (RHSBase && LHSBase == RHSBase) {
// We have common bases, fold the icmp to a constant based on the
// offsets.
Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset);
Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset);
if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) {
SimplifiedValues[&I] = C;
++NumConstantPtrCmps;
return true;
}
}
}
// If the comparison is an equality comparison with null, we can simplify it
// for any alloca-derived argument.
if (I.isEquality() && isa<ConstantPointerNull>(I.getOperand(1)))
if (isAllocaDerivedArg(I.getOperand(0))) {
// We can actually predict the result of comparisons between an
// alloca-derived value and null. Note that this fires regardless of
// SROA firing.
bool IsNotEqual = I.getPredicate() == CmpInst::ICMP_NE;
SimplifiedValues[&I] = IsNotEqual ? ConstantInt::getTrue(I.getType())
: ConstantInt::getFalse(I.getType());
return true;
}
// Finally check for SROA candidates in comparisons.
Value *SROAArg;
DenseMap<Value *, int>::iterator CostIt;
if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) {
if (isa<ConstantPointerNull>(I.getOperand(1))) {
accumulateSROACost(CostIt, InlineConstants::InstrCost);
return true;
}
disableSROA(CostIt);
}
return false;
}
bool GambasPass::runOnFunction(Function &F){
IRBuilder<> Builder(F.getContext());
bool changed = false;
for(Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
for(BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ){
ICmpInst* ICI = dyn_cast<ICmpInst>(I);
CallInst* CI = dyn_cast<CallInst>(I++);
if (ICI && ICI->hasMetadata() && ICI->getMetadata("unref_slt") && dyn_cast<LoadInst>(ICI->getOperand(0))){
ICI->replaceAllUsesWith(ConstantInt::get(ICI->getType(), false));
ICI->eraseFromParent();
changed = true;
continue;
}
if (!CI)
continue;
Function* callee = CI->getCalledFunction();
if (callee == NULL || !callee->isDeclaration())
continue;
StringRef name = callee->getName();
if (name == "JR_release_variant" || name == "JR_borrow_variant"){
ConstantInt* vtype_int = dyn_cast<ConstantInt>(CI->getArgOperand(0));
if (!vtype_int)
continue;
uint64_t vtype = vtype_int->getZExtValue();
if (TYPE_is_string(vtype) || TYPE_is_object(vtype))
continue;
CI->eraseFromParent();
changed = true;
} else if (name == FUNCTION_NAME(__finite)){
ConstantFP* op = dyn_cast<ConstantFP>(CI->getArgOperand(0));
if (!op)
continue;
int val = __finite(op->getValueAPF().convertToDouble());
Constant* res = ConstantInt::get(CI->getType(), val);
CI->replaceAllUsesWith(res);
CI->eraseFromParent();
changed = true;
} else if (name == FUNCTION_NAME(__isnan)){
ConstantFP* op = dyn_cast<ConstantFP>(CI->getArgOperand(0));
if (!op)
continue;
int val = __isnan(op->getValueAPF().convertToDouble());
Constant* res = ConstantInt::get(CI->getType(), val);
CI->replaceAllUsesWith(res);
CI->eraseFromParent();
changed = true;
} else if (name == FUNCTION_NAME(__isinf)){
ConstantFP* op = dyn_cast<ConstantFP>(CI->getArgOperand(0));
if (!op)
continue;
int val = __isinf(op->getValueAPF().convertToDouble());
Constant* res = ConstantInt::get(CI->getType(), val);
CI->replaceAllUsesWith(res);
CI->eraseFromParent();
changed = true;
}
}
}
return changed;
}
