Patches have been submitted by ARM to address the new Straight Line Speculation (SLS) vulnerability.
Using this bug to keep track of the status upstream, and then to determine what we do in Gentoo (like before, bug 646758, but maybe with more success here).
Patch series: https://gcc.gnu.org/pipermail/gcc-patches/2020-June/547520.html
To be clear, I do not expect toolchain@ to add these patches themselves before they are accepted upstream -- this is just to keep track.
The fixes are being backported to 9.x and 10.x: https://gcc.gnu.org/pipermail/gcc-patches/2020-July/550369.html.