- for (unsigned i = 0, ie = Scopes->getNumOperands(); i != ie; ++i)
- if (const MDNode *SMD = dyn_cast<MDNode>(Scopes->getOperand(i)))
- for (unsigned j = 0, je = NoAlias->getNumOperands(); j != je; ++j)
- if (const MDNode *NAMD = dyn_cast<MDNode>(NoAlias->getOperand(j)))
- if (!mayAlias(SMD, NAMD))
- return false;
+ // Collect the set of scope domains relevant to the noalias scopes.
+ SmallPtrSet<const MDNode *, 16> Domains;
+ for (unsigned i = 0, ie = NoAlias->getNumOperands(); i != ie; ++i)
+ if (const MDNode *NAMD = dyn_cast<MDNode>(NoAlias->getOperand(i)))
+ if (const MDNode *Domain = AliasScopeNode(NAMD).getDomain())
+ Domains.insert(Domain);
+
+ // We alias unless, for some domain, the set of noalias scopes in that domain
+ // is a superset of the set of alias scopes in that domain.
+ for (const MDNode *Domain : Domains) {
+ SmallPtrSet<const MDNode *, 16> NANodes, ScopeNodes;
+ collectMDInDomain(NoAlias, Domain, NANodes);
+ collectMDInDomain(Scopes, Domain, ScopeNodes);
+ if (!ScopeNodes.size())
+ continue;
+
+ // To not alias, all of the nodes in ScopeNodes must be in NANodes.
+ bool FoundAll = true;
+ for (const MDNode *SMD : ScopeNodes)
+ if (!NANodes.count(SMD)) {
+ FoundAll = false;
+ break;
+ }
+
+ if (FoundAll)
+ return false;
+ }