https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87733
--- Comment #27 from Rich Felker <bugdal at aerifal dot cx> --- Also just realized: > Rich, forcing "n" to be in "$r10" seems to do the trick? Is that a reasonable solution for you? It doesn't even work, because the syscall clobbers basically all call-clobbered registers. Current kernels are preserving at least $25 (t9) and $28 (gp) and the syscall argument registers, so $25 may be usable, but it was deemed not clear in 2012. I'm looking back through musl git history, and this is actually why the "i" alternative was wanted -- in basically all uses, "i" is satisfiable, and avoids needing to setup a stack frame and spill a call-saved register to the stack in order to use it to hold the syscall number to reload on restart.
