adjust codegen of casting between arrays and vectors

* bitcasting is still better when the size_in_bits aligns with the ABI
   size of the element type. Logic is reworked to do bitcasting when
   possible
 * rather than using insertelement/extractelement to work with arrays,
   store/load elements directly. This matches codegen for arrays
   elsewhere.
558b4ac1f0Andrew Kelley committed on 9/18/2019, 2:24:28 PMparent0e3ca4c
2 files changedLine totals unavailable