jthackray wrote: > LGTM. Does this actually fix the build time regression from the previous > patch?
Apologies for the delay; I wasn't working yesterday. Using a Graviton c8g.8xlarge instance, with a `ninja` build, I don't see a large build time regression. However, this is compiling in parallel, and I appreciate that official `llvmbot` builders may be building sequentially, which may see them take (wall-clock) longer (even if CPU used time is similar). Build times are also quite compiler-dependent. GCC takes a _lot_ longer than clang, especially for the previously-mentioned RISC-V file `riscv_vector_builtin_cg.inc`, about 3.3MB in size, that gets #included. Using clang 18 to compile a full `ninja` build after a `ninja clean` of the entire `llvm-project` source tree: ``` Before CGBuiltin.cpp split: real 351.41 user 10275.13 sys 471.73 After CGBuiltin.cpp split: real 353.28 user 10342.80 sys 472.39 After removing superfluous header files: real 353.46 user 10337.66 sys 474.88 ``` i.e. 2 seconds longer build time. However, with gcc 13 compiling, using `ninja` a full build of `llvm-project`, I see: ``` Before CGBuiltin.cpp split: real 631.64 user 11160.92 sys 685.47 After CGBuiltin.cpp split: real 574.28 user 11214.63 sys 691.98 ``` If only `CGBuiltin.cpp` and `ARM.cpp` is touched/updated, I see a large difference (this was what prompted me to investigate originally as I was updating ARM intrinsics; it turns out the vast majority of the time is spent compiling the RISC-V code (`riscv_vector_builtin_cg.inc`, ~3.3MB in size) which was previously #included in `CGBuiltin.cpp`): ``` clang 18 - before CGBuiltin.cpp split: real 35.47 user 39.84 sys 3.08 clang 18 - after split: real 16.00 user 30.02 sys 3.44 ``` and: ``` gcc 13 - before CGBuiltin.cpp split: real 397.02 (yes, it takes 5 minutes on Graviton 4 to recompile CGBuiltin.cpp) user 400.35 sys 5.54 gcc 13 - after split: real 49.55 user 65.88 sys 5.29 ``` https://github.com/llvm/llvm-project/pull/132495 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
