Vector: Remove now unnecessary uses of undefined #552
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Sail 0.18 contains the vector_init primitive, to make initialising vectors with defined values easier. We can use this in some places where the vector code was creating an uninitalised vector, only to then initialize it later. Second, we can remove some uses of undefined by refactoring slightly how init_masked_result is used, which has the added benefit of making mask immutable. Some additional constraints need to be added to use the vector_init primitive. Sail's pattern completeness checker is now smarter than before, so some wildcard cases can also be safely removed.
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A few refactorings to the vector extension:
Sail 0.18 contains the vector_init primitive, to make initialising vectors with defined values easier. We can use this in some places where the vector code was creating an uninitialised vector, only to then initialise it later.
Second, we can remove some uses of undefined by refactoring slightly how
init_masked_resultis used, which has the added benefit of making the mask immutable.Sail's pattern completeness checker is now smarter than before, so some wildcard cases in matches can also be safely removed without causing any warnings.
We can also remove some asserts by adding an overload for the default division operator for the positive cases where truncating division and the SMT solver's euclidian division are the same, so the type system can just infer the facts those assertions were guaranteeing.
One thing I noticed is the
read_vmask_carryfunction doesn't seem to be doing anything, as it looks like it is only called withvm=0b0where it is then the same asread_vmask. I didn't make any changes to this in this PR however.