Excerpts from Segher Boessenkool's message of February 25, 2022 3:29 am: > On Thu, Feb 24, 2022 at 09:13:25PM +1000, Nicholas Piggin wrote: >> Excerpts from Arnd Bergmann's message of February 24, 2022 8:20 pm: >> > Again, there should be a minimum number of those .machine directives >> > in inline asm as well, which tends to work out fine as long as the >> > entire kernel is built with the correct -march= option for the minimum >> > supported CPU, and stays away from inline asm that requires a higher >> > CPU level. >> >> There's really no advantage to them, and they're ugly and annoying >> and if we applied the concept consistently for all asm they would grow >> to a very large number. > > The advantage is that you get machine code that *works*. There are > quite a few mnemonics that translate to different instructions with > different machine options! We like to get the intended instructions > instead of something that depends on what assembler options the user > has passed behind our backs. > >> The idea they'll give you good static checking just doesn't really >> pan out. > > That never was a goal of this at all. > > -many was very problematical for GCC itself. We no longer use it. You have the wrong context. We're not talking about -many vs .machine here. Thanks, Nick
