swift

181b2f1f - Optimizer: eliminate `struct_extract`s of an owned `struct` where the `struct_extract`s are inside a borrow scope

Optimizer: eliminate `struct_extract`s of an owned `struct` where the `struct_extract`s are inside a borrow scope This is done by splitting the `begin_borrow` of the whole struct into individual borrows of the fields (for trivial fields no borrow is needed). And then sinking the `struct` to it's consuming use(s). ``` %3 = struct $S(%nonTrivialField, %trivialField) // owned ... %4 = begin_borrow %3 %5 = struct_extract %4, #S.nonTrivialField %6 = struct_extract %4, #S.trivialField use %5, %6 end_borrow %4 ... end_of_lifetime %3 ``` -> ``` ... %5 = begin_borrow %nonTrivialField use %5, %trivialField end_borrow %5 ... %3 = struct $S(%nonTrivialField, %trivialField) end_of_lifetime %3 ``` This optimization is important for Array code where the Array buffer is constantly wrapped into structs and then extracted again to access the buffer.