search for: copy_if_different

...stimate is adjusted down to only a couple of hundred in many cases probably due to this. I can confirm that tablegen-erated files do the right thing and that it's based on the output of tablegen. Our cmake scripts do it by having llvm-tblgen write to a temporary file and then use 'cmake -E copy_if_different' to update the real one when necessary. Once ninja has run the copy_if_different command it re-checks the dependencies and culls the ones it doesn't need. > On Fri, Jul 7, 2017 at 6:47 AM Nemanja Ivanovic via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org&...

Hi everyone, I have felt for quite some time that during my regular LLVM workflow, CMake recompiles a lot of files after I update to the latest ToT (which I do more than once per week). Of course, this wasn't really based on any real data, just felt like every time I update (even if it's a day or two later), we end up recompiling everything. For a while I assumed that patches touch a few

FWIW, tablegen does not update timestamps for .inc files, if their contents is unchanged, so if you somehow affect a .td file's timestamp (without changing its contents) it will trigger rebuild of the corresponding .inc file with all subsequent incremental make builds. At the same time, this will not trigger rebuilding any targets dependent on this .inc file, since it is not modified. From