jasonliu added inline comments.
================ Comment at: clang/test/CodeGen/ppc32-struct-return.c:53 + +// AIX-SVR4: fatal error: error in backend: -msvr4-struct-return not supported on AIX + ---------------- jasonliu wrote: > sfertile wrote: > > jasonliu wrote: > > > If certain front end option is not supported on certain target, I think > > > it makes more sense to have a standard diagnostic in the driver > > > component, instead of "crash" in the backend. > > > i.e. What if we specify this option on a Windows machine? Maybe we should > > > pursue the same behavior. > > Its not that we don't intend to support the option on AIX, but that support > > for the option takes further verification on AIX. Since there is a > > difference how AIX justifies subregister sized values in its argument > > passing, we can't just assume that this option will pack the return values > > the same way on AIX and Linux. > > > > The focus of this patch was originally to enable and verify the proper IR > > generation of va-arg/va-lis/va-start, however the scope of the patch has > > kept growing. If there are codegen differences in packing the return > > register with the svr4-return option enabled it will grow this patch once > > again. The fatal error lets us limit the scope of this patch, while not > > silently emiting bad codegen if there is a difference in how gcc > > initializes the return registers. If during verification we decide we > > don't want to support the option on AIX, then adopting a standard > > diagnostic in the driver component becomes the appropriate behavior. > It wasn't clear for me from the code that this is not a permanent thing. In > that case, does it make sense to leave a TODO here and say we need to > re-evaluate this in the future to decide if we want to support it or not on > AIX? > On another note, I'm not sure if this is really needed on AIX target though. > But I guess we could discuss it down the road. Just to avoid ambiguity, I meant I'm not sure if we really need this *option* on AIX. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D76360/new/ https://reviews.llvm.org/D76360 _______________________________________________ cfe-commits mailing list firstname.lastname@example.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits