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Do I understand correctly this is the fix and the removal of nop shifts is a separate optimization, or is that required as well?
FWIW, I would prefer we not do these ad-hoc opts in lowering (instead tracing back the where the frontend "failed at its job" and so on).
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@SingleAccretion it's pretty normal to duplicate peepholes accross phases and we already do it. Front-end didn't fail here, only rationalizer managed to fold this:
into
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maybe some day we'll get a DSL for transformations which will be compiled into morph and lower at the same time (that's how some C++ compilers work today)
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Is it really worth to add this optimization in lower that only has hits in fuzzer generated code?
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@jakobbotsch not really, but the diff found 4 more cases and we still don't have collections for real-world apps to judge. but let me remove it since it raised concerns by you two
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PTAL