GCC aligns global data to 16 bytes if their size is >= 16 bytes. This patch
changes the exp_data struct slightly so that the fields are better aligned
and without gaps. As a result on targets that support them, more load-pair
instructions are used in exp.
The exp benchmark improves 2.5%, "144bits" by 7.2%, "768bits" by 12.7% on
Neoverse V2.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 5afaf99edb326fd9f36eb306a828d129a3a1d7f7)
(cherry picked from commit 5a08d049dc5037e89eb95bb1506652f0043fa39e)