https://github.com/cgmb commented:
Thanks @yxsamliu! To add a bit more context, this was my original email that raised the topic: > I wonder if we should consider revisiting the decision to default clang to > gfx906 [1]. I came across how that decision was made shortly after it was > implemented, and at the time I thought it was silly not to default to > `native`. The decision was made to change the default from gfx803 to gfx906 > because the former wasn’t supported, but AMD dropped support for the latter > shortly thereafter. Using the same criteria as that previous decision, we > should be changing the default again to something newer. > > However, the default of "some random GPU architecture that changes every few > releases" is just plain bad. If a user tries to run a program that was built > for gfx906 only because nothing else was specified, the most likely result > will be that the program doesn’t work on their machine. I’m not sure what the > current behaviour of the HIP Runtime is, but historically, running a program > built for a different GPU than your own would result in a crash that might > not even include an error message. > > My workstations all have gfx906 GPUs, but this is arguably worse! It means > that when I work on build scripts, if I make a mistake and fail to specify > the target architecture somewhere, the built result will still work on my > machine! This hides errors in my build scripts, which then become a problem > when I share those scripts with others working on different hardware. Even > for my own work, I wouldn’t want to depend on gfx906 being the default > target. My scripts would all break when I update clang to some future version. > > I would suggest that we should either (a) change the default GPU target to > `native` and make the failure to detect the user’s GPU into a hard compiler > error, or (b) change the default GPU target to SPIR-V so that it works on > every machine. > > [1]: > https://discourse.llvm.org/t/rfc-let-clang-use-system-gpu-as-default-offload-arch-for-hip/66950/5 https://github.com/llvm/llvm-project/pull/139281 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
