// TODO: Try to normalize newly added/modified edge.
}
+ // Does this Cost vector have any register options ?
+ template <typename VectorT>
+ bool hasRegisterOptions(const VectorT &V) {
+ unsigned VL = V.getLength();
+
+ // An empty or spill only cost vector does not provide any register option.
+ if (VL <= 1)
+ return false;
+
+ // If there are registers in the cost vector, but all of them have infinite
+ // costs, then ... there is no available register.
+ for (unsigned i = 1; i < VL; ++i)
+ if (V[i] != std::numeric_limits<PBQP::PBQPNum>::infinity())
+ return true;
+
+ return false;
+ }
// \brief Find a solution to a fully reduced graph by backpropagation.
//
RawVector v = G.getNodeCosts(NId);
+ // Although a conservatively allocatable node can be allocated to a register,
+ // spilling it may provide a lower cost solution. Assert here that spilling
+ // is done by choice, not because there were no register available.
+ if (G.getNodeMetadata(NId).isConservativelyAllocatable())
+ assert(hasRegisterOptions(v) && "A conservatively allocatable node "
+ "must have available register options");
+
for (auto EId : G.adjEdgeIds(NId)) {
const Matrix& edgeCosts = G.getEdgeCosts(EId);
if (NId == G.getEdgeNode1Id(EId)) {