wenlei added a comment. In D77484#1965976 <https://reviews.llvm.org/D77484#1965976>, @tejohnson wrote:
> In D77484#1965629 <https://reviews.llvm.org/D77484#1965629>, @wenlei wrote: > > > > Ok then it does sound like these could be handled on a per-function > > > basis, similar to how -fno-builtin* are handled. I.e. a function > > > attribute to indicate the veclib, which would then be naturally preserved > > > during LTO even after merging/importing across modules. Similar to how > > > -fno-builtin* are handled, these would need to be examined when inlining > > > (see the new TargetLibraryInfo::areInlineCompatible). Presumably we would > > > want to block inlining between functions with different veclib attributes > > > in the LTO backends. > > > > @tejohnson, we could do that. But then on the other hand, technically > > almost everything for module or whole program can be passed as a function > > attribute, and yet we have switches passed to backend for many of those > > things. Wondering what's the convention or rule (if there's one) we want to > > follow? Specifically, if we only use function attributes for stuff that's > > indeed going to be different between functions, then vectlib isn't in that > > category; or if we use function attributes for the greatest flexibility > > whenever we can, then many other things should be function attributes too > > (though it's essentially duplication in IR, and probably not the most > > efficient). > > > Passing the option through the driver to the linker is the legacy approach. > But it isn't really scalable and has other issues, so we've been moving > towards having all the necessary info in the IR itself. For one, this helps > deal with cases where different options were specified for different source > files. For another, it keeps the same build behavior with LTO and non-LTO. > I.e. for this option, if the build system specified it for the cc compiles > but not the links, it would work for O2 > <https://reviews.llvm.org/owners/package/2/> but not for LTO if it had to be > propagated via the linker. It would work for LTO if it was propagated via the > IR. Makes sense, thanks for clarification. I created D77632 <https://reviews.llvm.org/D77632> to make vect lib setting a per-function attribute. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D77484/new/ https://reviews.llvm.org/D77484 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
