+ // Undefined shuffle mask -> undefined value.
+ if (isa<UndefValue>(Mask)) return UndefValue::get(V1->getType());
+
+ unsigned MaskNumElts = cast<VectorType>(Mask->getType())->getNumElements();
+ unsigned SrcNumElts = cast<VectorType>(V1->getType())->getNumElements();
+ const Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
+
+ // Loop over the shuffle mask, evaluating each element.
+ SmallVector<Constant*, 32> Result;
+ for (unsigned i = 0; i != MaskNumElts; ++i) {
+ Constant *InElt = GetVectorElement(Mask, i);
+ if (InElt == 0) return 0;
+
+ if (isa<UndefValue>(InElt))
+ InElt = UndefValue::get(EltTy);
+ else if (ConstantInt *CI = dyn_cast<ConstantInt>(InElt)) {
+ unsigned Elt = CI->getZExtValue();
+ if (Elt >= SrcNumElts*2)
+ InElt = UndefValue::get(EltTy);
+ else if (Elt >= SrcNumElts)
+ InElt = GetVectorElement(V2, Elt - SrcNumElts);
+ else
+ InElt = GetVectorElement(V1, Elt);
+ if (InElt == 0) return 0;
+ } else {
+ // Unknown value.
+ return 0;
+ }
+ Result.push_back(InElt);
+ }
+
+ return ConstantVector::get(&Result[0], Result.size());
+}
+
+Constant *llvm::ConstantFoldExtractValueInstruction(const Constant *Agg,
+ const unsigned *Idxs,
+ unsigned NumIdx) {
+ // Base case: no indices, so return the entire value.
+ if (NumIdx == 0)
+ return const_cast<Constant *>(Agg);
+
+ if (isa<UndefValue>(Agg)) // ev(undef, x) -> undef
+ return UndefValue::get(ExtractValueInst::getIndexedType(Agg->getType(),
+ Idxs,
+ Idxs + NumIdx));
+
+ if (isa<ConstantAggregateZero>(Agg)) // ev(0, x) -> 0
+ return
+ Constant::getNullValue(ExtractValueInst::getIndexedType(Agg->getType(),
+ Idxs,
+ Idxs + NumIdx));
+
+ // Otherwise recurse.
+ return ConstantFoldExtractValueInstruction(Agg->getOperand(*Idxs),
+ Idxs+1, NumIdx-1);
+}
+
+Constant *llvm::ConstantFoldInsertValueInstruction(const Constant *Agg,
+ const Constant *Val,
+ const unsigned *Idxs,
+ unsigned NumIdx) {
+ // Base case: no indices, so replace the entire value.
+ if (NumIdx == 0)
+ return const_cast<Constant *>(Val);
+
+ if (isa<UndefValue>(Agg)) {
+ // Insertion of constant into aggregate undef
+ // Optimize away insertion of undef
+ if (isa<UndefValue>(Val))
+ return const_cast<Constant*>(Agg);
+ // Otherwise break the aggregate undef into multiple undefs and do
+ // the insertion
+ const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
+ unsigned numOps;
+ if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
+ numOps = AR->getNumElements();
+ else
+ numOps = cast<StructType>(AggTy)->getNumElements();
+ std::vector<Constant*> Ops(numOps);
+ for (unsigned i = 0; i < numOps; ++i) {
+ const Type *MemberTy = AggTy->getTypeAtIndex(i);
+ const Constant *Op =
+ (*Idxs == i) ?
+ ConstantFoldInsertValueInstruction(UndefValue::get(MemberTy),
+ Val, Idxs+1, NumIdx-1) :
+ UndefValue::get(MemberTy);
+ Ops[i] = const_cast<Constant*>(Op);
+ }
+ if (isa<StructType>(AggTy))
+ return ConstantStruct::get(Ops);
+ else
+ return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
+ }
+ if (isa<ConstantAggregateZero>(Agg)) {
+ // Insertion of constant into aggregate zero
+ // Optimize away insertion of zero
+ if (Val->isNullValue())
+ return const_cast<Constant*>(Agg);
+ // Otherwise break the aggregate zero into multiple zeros and do
+ // the insertion
+ const CompositeType *AggTy = cast<CompositeType>(Agg->getType());
+ unsigned numOps;
+ if (const ArrayType *AR = dyn_cast<ArrayType>(AggTy))
+ numOps = AR->getNumElements();
+ else
+ numOps = cast<StructType>(AggTy)->getNumElements();
+ std::vector<Constant*> Ops(numOps);
+ for (unsigned i = 0; i < numOps; ++i) {
+ const Type *MemberTy = AggTy->getTypeAtIndex(i);
+ const Constant *Op =
+ (*Idxs == i) ?
+ ConstantFoldInsertValueInstruction(Constant::getNullValue(MemberTy),
+ Val, Idxs+1, NumIdx-1) :
+ Constant::getNullValue(MemberTy);
+ Ops[i] = const_cast<Constant*>(Op);
+ }
+ if (isa<StructType>(AggTy))
+ return ConstantStruct::get(Ops);
+ else
+ return ConstantArray::get(cast<ArrayType>(AggTy), Ops);
+ }
+ if (isa<ConstantStruct>(Agg) || isa<ConstantArray>(Agg)) {
+ // Insertion of constant into aggregate constant
+ std::vector<Constant*> Ops(Agg->getNumOperands());
+ for (unsigned i = 0; i < Agg->getNumOperands(); ++i) {
+ const Constant *Op =
+ (*Idxs == i) ?
+ ConstantFoldInsertValueInstruction(Agg->getOperand(i),
+ Val, Idxs+1, NumIdx-1) :
+ Agg->getOperand(i);
+ Ops[i] = const_cast<Constant*>(Op);
+ }
+ Constant *C;
+ if (isa<StructType>(Agg->getType()))
+ C = ConstantStruct::get(Ops);
+ else
+ C = ConstantArray::get(cast<ArrayType>(Agg->getType()), Ops);
+ return C;
+ }
+