[llvm] [Attributor]: allow more than one offset for a pass through user in AAPointerInfo (PR #94416)

[Johannes Doerfert via llvm-commits]

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@@ -1607,11 +1607,20 @@ ChangeStatus AAPointerInfoFloating::updateImpl(Attributor &A) {
     //
     // The RHS is a reference that may be invalidated by an insertion caused by
     // the LHS. So we ensure that the side-effect of the LHS happens first.
+
+    if (!OffsetInfoMap.contains(Usr)) {
+      auto &UsrOI = OffsetInfoMap[Usr];
+      auto &PtrOI = OffsetInfoMap[CurPtr];
+      UsrOI = PtrOI;
+      Follow = true;
+      return true;
+    }
+
     auto &UsrOI = OffsetInfoMap[Usr];
     auto &PtrOI = OffsetInfoMap[CurPtr];
     assert(!PtrOI.isUnassigned() &&
            "Cannot pass through if the input Ptr was not visited!");
-    UsrOI = PtrOI;
+    UsrOI.merge(PtrOI);
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jdoerfert wrote:

We need a test.

https://github.com/llvm/llvm-project/pull/94416