pengfei added a comment. In D118527#3281488 <https://reviews.llvm.org/D118527#3281488>, @craig.topper wrote:
> I believe the design here was supposed to be that "generic" would be updated > in X86.td on an ongoing basis to be more modern. So that if users pass > -mtune=generic it would evolve over time. > > This matches gcc behavior > > ‘generic’ > Produce code optimized for the most common IA32/AMD64/EM64T processors. If > you know the CPU on which your code will run, then you should use the > corresponding -mtune or -march option instead of -mtune=generic. But, if you > do not know exactly what CPU users of your application will have, then you > should use this option. > > As new processors are deployed in the marketplace, the behavior of this > option will change. Therefore, if you upgrade to a newer version of GCC, code > generation controlled by this option will change to reflect the processors > that are most common at the time that version of GCC is released. > > There is no -march=generic option because -march indicates the instruction > set the compiler can use, and there is no generic instruction set applicable > to all processors. In contrast, -mtune indicates the processor (or, in this > case, collection of processors) for which the code is optimized. Thanks for the information, I'll try the other way, thanks Craig! Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D118527/new/ https://reviews.llvm.org/D118527 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
