On Thu, Nov 7, 2024 at 9:00 AM Jakub Jelinek <ja...@redhat.com> wrote: > > On Thu, Nov 07, 2024 at 08:47:34AM +0100, Uros Bizjak wrote: > > Maybe we should always recognize "redzone", even for targets without > > it. This is the way we recognize "cc" even for targets without CC reg > > (e.g. alpha). This would simplify the definition and processing - if > > the hook returns NULL_RTX (the default), then it (obviously) won't be > > added to the clobber list. > > Dunno, am open to that, but thought it would be just weird if one says > "redzone" on targets which don't have such a concept.
Let's look at the situation with x86_32 and x86_64. The "redzone" for the former is just an afterthought, so we can safely say that it doesn't support it. So, the code that targets both targets (e.g. linux kernel) would (in a pedantic way) have to redefine many shared asm defines, one to have clobber and one without it. We don't want that, we want one definition and "let's compiler sort it out". For targets without clobber concept, well - don't add it to the clobber list if it is always ineffective. One *can* add "cc" to all alpha asms, but well.. ;) Uros.
