thakis added a comment. In https://reviews.llvm.org/D52193#1241067, @aganea wrote:
> @thakis > clang-cl isn't supposed to do (explicit) registry accesses when you > hold it right (pass in -fms-compatibility-version etc). Have you seen > registry access costs, or is that speculation? > > Please see this log: F7268226: clang-cl-log.zip > <https://reviews.llvm.org/F7268226> - the child `clang-cl -cc1` takes about > ~117ms until it gets into the global initializers. This is on my Haswell PC. > On the Skylake, this takes "only" ~60ms. > This probably explains why Ninja is slower on the Skylake when using > `clang-cl` as a compiler. There should be a shorter codepath maybe when only > a single .cpp is being compiled, and avoid running the child process. Huh, interesting! I had a local hack years ago where I had measured how much not spawning a subprocess for cc1 saves (it looked like https://reviews.llvm.org/D52411) and over here it didn't do anything. Can you check if patching that in helps you a lot? If so, we should reconsider doing something like that. Repository: rC Clang https://reviews.llvm.org/D52193 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
