[Bug target/112470] [11/12/13/14 regression] [AARCH64] stack-protector vulnerability fixing solution impact code size and performance

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112470

--- Comment #10 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The instruction increase is 2:
        sub     sp, sp, #128
...
        stp     x29, x30, [sp, 112]

vs:
        stp     x29, x30, [sp, -128]!


and
        ldp     x29, x30, [sp, 112]
...
        add     sp, sp, 128

vs:
        ldp     x29, x30, [sp], 128

Depending on the core, the performance might be the same.

Without a full performance testcase which shows the difference, it is hard to
tell if this is an issue overall or just some one that shows up in one small
testcase.