On December 15, 2017 8:10:33 PM GMT+01:00, Jeff Law <l...@redhat.com> wrote: >On 12/14/2017 12:32 PM, Richard Biener wrote: >> >> On x86_64 all xmm registers are caller saved for example. That means >all FP regs and all vectors. (yeah, stupid ABI decision....) >But that's precisely what I would expect if one was looking to maintain >backwards compatibility within the core runtime libraries. > >If you make something callee-saved, then you have to have space for it >in the setjmp buffer. Expanding that buffer is an ABI change and thus >*highly* discouraged.
Yes. But the initial 64bit ABI already had 8 xmm regs. Probably all used for parameter passing as well, but... For all further extensions I agree. Richard. >jeff
