[flang-commits] [flang] [flang] Use fir.declare/fir.dummy_scope for TBAA tags attachments. (PR #92472)

[Tom Eccles via flang-commits]

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@@ -30,8 +30,15 @@ using namespace mlir;
 
 static bool isDummyArgument(mlir::Value v) {
   auto blockArg{mlir::dyn_cast<mlir::BlockArgument>(v)};
-  if (!blockArg)
+  if (!blockArg) {
+    auto defOp = v.getDefiningOp();
+    if (defOp) {
+      if (auto declareOp = mlir::dyn_cast<fir::DeclareOp>(defOp))
+        if (declareOp.getDummyScope())
+          return true;
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tblah wrote:

This will work for TBAA because of the separate trees.

I'm worried users of `fir::AliasAnalysis::alias` might get confused here. It will see a dummy argument and then say it doesn't alias, but that dummy argument will definitely alias with something in the function into which it was inlined.

https://github.com/llvm/llvm-project/pull/92472