+ // Expand any composed subreg indices.
+ // If dsub_2 has ComposedOf = [qsub_1, dsub_0], and this register has a
+ // qsub_1 subreg, add a dsub_2 subreg. Keep growing Indices and process
+ // expanded subreg indices recursively.
+ for (unsigned i = 0; i != Indices.size(); ++i) {
+ CodeGenSubRegIndex *Idx = Indices[i];
+ const CodeGenSubRegIndex::CompMap &Comps = Idx->getComposites();
+ CodeGenRegister *SR = SubRegs[Idx];
+ const SubRegMap &Map = SR->getSubRegs(RegBank);
+
+ // Look at the possible compositions of Idx.
+ // They may not all be supported by SR.
+ for (CodeGenSubRegIndex::CompMap::const_iterator I = Comps.begin(),
+ E = Comps.end(); I != E; ++I) {
+ SubRegMap::const_iterator SRI = Map.find(I->first);
+ if (SRI == Map.end())
+ continue; // Idx + I->first doesn't exist in SR.
+ // Add I->second as a name for the subreg SRI->second, assuming it is
+ // orphaned, and the name isn't already used for something else.
+ if (SubRegs.count(I->second) || !Orphans.erase(SRI->second))
+ continue;
+ // We found a new name for the orphaned sub-register.
+ SubRegs.insert(std::make_pair(I->second, SRI->second));
+ Indices.push_back(I->second);
+ }
+ }
+