hahnjo wrote: ### Performance measurements with LLVM
I tested these patches for building LLVM itself with modules (`LLVM_ENABLE_MODULES=ON`). To work around https://github.com/llvm/llvm-project/issues/130795, I apply https://github.com/llvm/llvm-project/pull/131354 before building Clang. In terms of overall performance for the entire build, I'm not able to measure a difference in memory consumption because that is dominated by the linker. The run time performance is very noisy, so it's hard to make accurate statements but it looks unaffected as well. I did some measurements for individual files, chosen by searching for large object files and excluding generated files. For each version, I first build LLVM completely to populate the `module.cache` and then delete and rebuild only one object file. Run time performance is not hugely affected, it seems to get slightly faster with this PR. `Maximum resident set size (kbytes)` from `/usr/bin/time -v`: | object file | before* | `main` | this PR | | --- | --- | --- | --- | | `lib/Analysis/CMakeFiles/LLVMAnalysis.dir/ScalarEvolution.cpp.o` | 543100 | 515184 | 445784 | | `lib/Passes/CMakeFiles/LLVMPasses.dir/PassBuilder.cpp.o` | 923036 | 884160 | 805960 | | `lib/Transforms/IPO/CMakeFiles/LLVMipo.dir/AttributorAttributes.cpp.o` | 639184 | 600076 | 522512 | | `lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/SLPVectorizer.cpp.o` | 876580 | 857404 | 776572 | before*: reverting fb2c9d940ad87e6ae09e06c6915e0c925a4f87ec, c5e4afe6733c58e24023ede04275bbed3bde8240, 30ea0f0ce476bf4c12684a9a514af2ca660bbe44, 20e904950967c125abc1e91f57e5a373987ff016 on current `main` https://github.com/llvm/llvm-project/pull/133057 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
