Hacker News Reader

The article lists features potentially responsible for Clang's gaining popularity, among them was fast compile times. I've always read that LLVM's compile times are terrible and that is, for instance, one of the reasons for Rusts slow compile times. Has this changed or is he only making claims about the Clang front end?

View on HN

I haven't used clang much in recent years but i remember back when it was first introduced clang was faster than gcc while producing only slightly slower (or sometimes comparable) code.

Most likely compile times slowed down as clang and llvm became more complex, but early clang was faster enough for people to switch to it - and then just stayed with it (this isn't a unique case, people switched to Chrome from Firefox because Chrome was much faster and they stayed with Chrome even after Chrome became slower and Firefox faster).

In any case the comparison was with gcc (and perhaps msvc), not all types of compilers.

I haven't seen any recent comparisons but the most recent benchmark I saw was that gcc/clang were close. I'm sure the speeds vary quite a bit depending on project size, options, available RAM, etc. IIRC using LTO makes linking significantly more resource intensive and I would assume this is where most of the disparities in performance are.

Reply on news.ycombinator.com