intel/lower_mem_access_bit_sizes: Compute alignments automatically

Because dup_mem_intrinsic() retains the SSA offset from the original
intrinsic and only modifies it by adding a constant, we can compute the
alignment based on the original alignment and the constant offset.  This
is both easier and more accurate.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19580>
1 file changed