njames93 added a comment. In D102369#2756493 <https://reviews.llvm.org/D102369#2756493>, @aaron.ballman wrote:
> I'm not opposed, but I don't know that this is really an improvement. We've > gone from a pretty simple code pattern to needing to spell out the type twice > with a type_trait, and all that we save is a call to `isa<>` within the > casting operation. While I agree this is strictly executing less code, it's > morally the same as the usual antipattern of "isa followed by cast should be > a dyn_cast". Is there evidence that this is a big performance win? In D102369#2756493 <https://reviews.llvm.org/D102369#2756493>, @aaron.ballman wrote: > I'm not opposed, but I don't know that this is really an improvement. We've > gone from a pretty simple code pattern to needing to spell out the type twice > with a type_trait, and all that we save is a call to `isa<>` within the > casting operation. While I agree this is strictly executing less code, it's > morally the same as the usual antipattern of "isa followed by cast should be > a dyn_cast". Is there evidence that this is a big performance win? To be honest, it would be much nicer if we could specialise `isa` to return false if there is From type is not a base class of the To type. However I'm not sure if that would break anything else. It's all part of the "Don't do at runtime whats known at compile time Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D102369/new/ https://reviews.llvm.org/D102369 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
