Add basic InstSimplify folds for CGetHigh and CSetFlags #697
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arichardson
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Now that we depend on C++14, we can use switches in constexpr functions and no longer need to pass two template parameters.
As part of this refactor some of the CHERI get intrinsics folding code. This refactoring introduces a minor change to getoffset folding as well: we no longer fold arbitrary getoffset(setoffset(A, B)) -> B since the setoffset could have changed the bounds interpretation and therefore also the result. This optimization is unlikely to make a difference in practise and is somewhat incorrect so I believe dropping it makes sense.
If we are setting the same value we just read we can simplify the sequence to just the original argument.
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Rebased, should hopefully be safe to merge. |
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Also some minor refactoring to allow sharing some code.
This somewhat regresses folding for CGetOffset but the existing fold was not safe.