+void RegisterMaps::computeComposites() {
+ for (SubRegMaps::const_iterator sri = SubReg.begin(), sre = SubReg.end();
+ sri != sre; ++sri) {
+ Record *Reg1 = sri->first;
+ const SubRegMap &SRM1 = sri->second;
+ for (SubRegMap::const_iterator i1 = SRM1.begin(), e1 = SRM1.end();
+ i1 != e1; ++i1) {
+ Record *Idx1 = i1->first;
+ Record *Reg2 = i1->second;
+ // Ignore identity compositions.
+ if (Reg1 == Reg2)
+ continue;
+ // If Reg2 has no subregs, Idx1 doesn't compose.
+ if (!SubReg.count(Reg2))
+ continue;
+ const SubRegMap &SRM2 = SubReg[Reg2];
+ // Try composing Idx1 with another SubRegIndex.
+ for (SubRegMap::const_iterator i2 = SRM2.begin(), e2 = SRM2.end();
+ i2 != e2; ++i2) {
+ std::pair<Record*,Record*> IdxPair(Idx1, i2->first);
+ Record *Reg3 = i2->second;
+ // OK Reg1:IdxPair == Reg3. Find the index with Reg:Idx == Reg3.
+ for (SubRegMap::const_iterator i1d = SRM1.begin(), e1d = SRM1.end();
+ i1d != e1d; ++i1d) {
+ // Ignore identity compositions.
+ if (Reg2 == Reg3)
+ continue;
+ if (i1d->second == Reg3) {
+ std::pair<CompositeMap::iterator,bool> Ins =
+ Composite.insert(std::make_pair(IdxPair, i1d->first));
+ // Conflicting composition?
+ if (!Ins.second && Ins.first->second != i1d->first) {
+ errs() << "Error: SubRegIndex " << getQualifiedName(Idx1)
+ << " and " << getQualifiedName(IdxPair.second)
+ << " compose ambiguously as "
+ << getQualifiedName(Ins.first->second) << " or "
+ << getQualifiedName(i1d->first) << "\n";
+ abort();
+ }
+ }
+ }
+ }
+ }
+ }
+
+ // We don't care about the difference between (Idx1, Idx2) -> Idx2 and invalid
+ // compositions, so remove any mappings of that form.
+ for (CompositeMap::iterator i = Composite.begin(), e = Composite.end();
+ i != e;) {
+ CompositeMap::iterator j = i;
+ ++i;
+ if (j->first.second == j->second)
+ Composite.erase(j);
+ }
+}
+