[PATCH] D27324: IPO: Introduce ThinLTOBitcodeWriter pass.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc added a comment.

With a timer for the thin-link phase (https://github.com/pcc/llvm-project/commit/9f389f9d1c16c34d32d040cfb55aa69e97d9ad9f) the timings are:

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   6.2637 ( 28.1%)   0.2148 ( 10.6%)   6.4785 ( 26.7%)   6.2113 ( 25.5%)  LTO::addRegularLTO
   5.1410 ( 23.1%)   0.6442 ( 31.7%)   5.7852 ( 23.8%)   5.7871 ( 23.8%)  LTO::runThinLTO thin-link
   5.1463 ( 23.1%)   0.5565 ( 27.4%)   5.7028 ( 23.5%)   5.7000 ( 23.4%)  lto::backend opt
   4.4082 ( 19.8%)   0.3652 ( 18.0%)   4.7735 ( 19.7%)   5.0972 ( 20.9%)  LTO::addThinLTO
   1.2965 (  5.8%)   0.2523 ( 12.4%)   1.5487 (  6.4%)   1.5487 (  6.4%)  lto::backend codegen
  22.2557 (100.0%)   2.0330 (100.0%)  24.2887 (100.0%)  24.3442 (100.0%)  Total

So that's 5.0972 + 5.7871 = 10.8843s for the sequential parts of ThinLTO and  6.2113 + 5.7000 + 1.5487 = 13.4600s for regular LTO.


https://reviews.llvm.org/D27324