+ /*
+ Perms inserted before the constraint handling phase are considered to be
+ correctly precolored. These Perms arise during the ABI handling phase.
+ */
+ if(insn->has_constraints) {
+ firm_dbg_module_t *dbg = alloc_env->constr_dbg;
+ const arch_env_t *aenv = env->birg->main_env->arch_env;
+ int n_regs = env->cls->n_regs;
+ bitset_t *bs = bitset_alloca(n_regs);
+ bitset_t *non_ignore = bitset_alloca(n_regs);
+ ir_node **alloc_nodes = alloca(n_regs * sizeof(alloc_nodes[0]));
+ bipartite_t *bp = bipartite_new(n_regs, n_regs);
+ int *assignment = alloca(n_regs * sizeof(assignment[0]));
+ pmap *partners = pmap_create();
+
+ int i, n_alloc;
+ long col;
+ const ir_edge_t *edge;
+ ir_node *perm = NULL;
+
+ /*
+ prepare the constraint handling of this node.
+ Perms are constructed and Copies are created for constrained values
+ interfering with the instruction.
+ */
+ perm = pre_process_constraints(alloc_env, &insn);
+
+ /* find suitable in operands to the out operands of the node. */
+ pair_up_operands(alloc_env, insn);
+
+ /*
+ look at the in/out operands and add each operand (and its possible partner)
+ to a bipartite graph (left: nodes with partners, right: admissible colors).
+ */
+ for(i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
+ operand_t *op = &insn->ops[i];
+
+ /*
+ If the operand has no partner or the partner has not been marked
+ for allocation, determine the admissible registers and mark it
+ for allocation by associating the node and its partner with the
+ set of admissible registers via a bipartite graph.
+ */
+ if(!op->partner || !pmap_contains(partners, op->partner->carrier)) {
+
+ pmap_insert(partners, op->carrier, op->partner ? op->partner->carrier : NULL);
+ alloc_nodes[n_alloc] = op->carrier;