https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110908
--- Comment #5 from zach-gcc at cs dot stanford.edu --- I am implementing software fault isolation on top of GCC and would like for GCC to only ever store addresses in x30. Use of x30 in its link register role is desired (saving/restoring etc. is good), but I would not like GCC to use x30 for general-purpose arithmetic. I'm not even sure that GCC ever does that to begin with, but LLVM does and the `-ffixed-x30` option prevents LLVM from doing so (while retaining x30's role as the link register).
