With -mcpu=generic the loop alignment is currently 4. All but one of the
supported cores use 8 or higher. Since using 8 provides performance gains
on several cores, it is best to use that by default. As discussed in [1],
the jump alignment has no effect on performance, yet has a relatively high
codesize cost [2], so setting it to 4 is best. This gives a 0.2% overall
codesize improvement as well as performance gains in several benchmarks.
gcc/
* config/aarch64/aarch64.c (generic_tunings): Set jump alignment to 4.
Set loop alignment to 8.
[1] https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00574.html
[2] https://gcc.gnu.org/ml/gcc-patches/2016-06/msg02075.html
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@247608 138bc75d-0d04-0410-961f-82ee72b054a4