[flang-commits] [flang] [flang] Use alias analysis in lowering record assignments (PR #176483)

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https://github.com/jeanPerier commented:

Thanks for fixing this.
The fix looks correct, I am worried about the performance impact of doing this for all derived types. have you measured performance impact on SPEC or other app/benchmarks?

As I understand it, only SEQUENCE type can lead to such situation.

I think it may be worth updating the fir.type representation so that it can hold the SEQUENCE aspect and that this change can be restricted to SEQUENCE types (see for instance what is done with the `pack` flag `fir.type` in FIRTypes.td

BTW, can you add a `-emit-fir` test for the case from the bug report which is the one where we want to test that the generated code is not assuming the members do not overlap?

https://github.com/llvm/llvm-project/pull/176483