On Thu, Jul 11, 2019 at 7:14 PM 'Nick Desaulniers' via Clang Built Linux <clang-built-linux@xxxxxxxxxxxxxxxx> wrote: > > On Thu, Jul 11, 2019 at 5:28 AM Arnd Bergmann <arnd@xxxxxxxx> wrote: > > clang does not like an inline assembly with a "=q" contraint for > > a 64-bit output: > > Seems like starting in GCC 7, GCC may not like it either: > https://godbolt.org/z/UyBUfh > it simply warns then proceeds with code gen. Another difference may > come from when GCC vs Clang perform dead code elimination (DCE) vs > semantic analysis. Right, I also had the idea to work around it with a set of __builtin_choos_expr() instead of the switch()/case but did not complete that patch as the percpu code is rather complex and this would touch lots of code. Arnd
