[Mlir-commits] [mlir] [mlir][Transforms] Dialect conversion: Simplify handling of dropped arguments (PR #96207)

[Markus Böck]

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@@ -246,6 +246,13 @@ depending on the situation.
 
     -   An argument materialization is used when converting the type of a block
         argument during a [signature conversion](#region-signature-conversion).
+        The new block argument types are specified in a `SignatureConversion`
+        object. An original block argument can be converted into multiple
+        block arguments, which is not supported everywhere in the dialect
+        conversion. (E.g., adaptors support only a single replacement value for
+        each original value.) Therefore, an argument materialization is used to
+        convert potentially multiple new block arguments back into a single SSA
+        value.
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zero9178 wrote:

Is this just for the purpose of adaptors? What is the type of that one single value (the old type?). This seems a bit odd from a consistency perspective as that means the adaptors sees a value of the old type, not new. I don't think this can be fixed either without transitioning to the 1toN adaptors but the limitation may be worth documenting here.

https://github.com/llvm/llvm-project/pull/96207