https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108968
--- Comment #6 from Andrew Cooper <andrew.cooper3 at citrix dot com> --- (In reply to David Malcolm from comment #5) > Minimal reproducer: https://godbolt.org/z/E6EEY1WT6 > > Am I right in understanding that: > register unsigned long sp asm("rsp"); > is intended as a way to read the %rsp register? Ultimately, yes. More generally, this just creates a way to access the specific register. It is the only way for example to create an asm constraint on e.g. %r8, so the following is common to see for MSABI: register unsigned long param asm ("%r8"); param = 4; asm ("tdcall/whatever" : "+r" (param) ...); (Example here is from Intel's new TDX technology, but the actual asm instruction isn't important.)
