MaskRay added inline comments.
================ Comment at: clang/include/clang/Driver/Options.td:3193 +def mskip_rax_setup : Flag<["-"], "mskip-rax-setup">, Group<m_Group>, Flags<[NoXarchOption]>, + HelpText<"Skip setting up RAX register when passing variable arguments (x86 only)">; def mstackrealign : Flag<["-"], "mstackrealign">, Group<m_Group>, Flags<[CC1Option]>, ---------------- nickdesaulniers wrote: > I think GCC support `-mno-skip-rax-setup` as well. Can you please add that > (and tests for it) as well? We don't need to actually handle it, I think, > but we shouldn't warn about the flag being unsupported, for example. Consider `SimpleMFlag` ================ Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:96 +static cl::opt<bool> SkipRaxSetup( + "x86-skip-rax-setup", cl::init(false), ---------------- nickdesaulniers wrote: > If it's a command line option rather than encoded in the IR, then this won't > be handled correctly under LTO (we support building the x86 linux kernel > under LTO), unless the linker re-passes the flag. I've been trying to avoid > that by encoding this information properly in IR rather than rely on codegen > command line options which I find brittle. Please see > https://reviews.llvm.org/D103928 as an example. This depends on how frequent the feature is used. I see that `arch/x86/Makefile` may add `-mskip-rax-setup` which is presumably used by all C files, so a module flag metadata suffices. If there are mix-and-match cases for different modules (e.g. ssp/nossp) a function attribute may be used. If a feature is really obscure than I might not consider wasting an IR attribute on it. Arguably if a feature is sufficient obscure we may not want to port it from GCC at all. So "This fixes pr23258." in the description should state the use case to give archaeologists a hint why the feature is added. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D112413/new/ https://reviews.llvm.org/D112413 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
