[llvm] [polly] [AST] Don't merge memory locations in AliasSetTracker (PR #65731)

[Bruno De Fraine via llvm-commits]

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@@ -317,62 +262,67 @@ AliasSet *AliasSetTracker::findAliasSetForUnknownInst(Instruction *Inst) {
 }
 
 AliasSet &AliasSetTracker::getAliasSetFor(const MemoryLocation &MemLoc) {
+  // The alias sets are indexed with a map from the memory locations' pointer
+  // values. If the memory location is already registered, we can find it in the
+  // alias set associated with its pointer.
+  AliasSet *&MapEntry = PointerMap[MemLoc.Ptr];
+  if (MapEntry) {
+    AliasSet *AS = MapEntry->getForwardedTarget(*this);
+    if (llvm::is_contained(AS->MemoryLocs, MemLoc)) {
+      if (AS != MapEntry) {
+        AS->addRef();
+        MapEntry->dropRef(*this);
+        MapEntry = AS;
+      }
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brunodf-snps wrote:

Yes, if MapEntry is pointing to a forwarding alias set, we change MapEntry to point to the forward target instead, so next time we end up there directly (and by removing the pointer to the forwarding alias set, it may get cleaned up).

https://github.com/llvm/llvm-project/pull/65731