[flang-commits] [flang] [flang] Remove materialization workaround in type converter (PR #98743)

[Matthias Springer via flang-commits]

matthias-springer wrote:

Note: Type conversions do not know the context in which they are converting a type. But each pattern can be initialized with a different type converter.

That's the basic idea behind this PR. I tried the same for the workaround in `XReboxOpConversion`, but without success:
```c++
    // Inside a fir.global, the input box was produced as an llvm.struct<>
    // because objects cannot be handled in memory inside a fir.global body that
    // must be constant foldable. However, the type translation are not
    // contextual, so the fir.box<T> type of the operation that produced the
    // fir.box was translated to an llvm.ptr<llvm.struct<>> and the MLIR pass
    // manager inserted a builtin.unrealized_conversion_cast that was inserted
    // and needs to be removed here.
    if (isInGlobalOp(rewriter))
      if (auto unrealizedCast =
              loweredBox.getDefiningOp<mlir::UnrealizedConversionCastOp>())
        loweredBox = unrealizedCast.getInputs()[0];
```

Maybe the type conversion in that pattern is truly context-specific.


https://github.com/llvm/llvm-project/pull/98743