[PATCH] D27324: IPO: Introduce ThinLTOBitcodeWriter pass.

[Peter Collingbourne via Phabricator via llvm-commits]

pcc added a comment.

Here are the results after applying https://github.com/pcc/llvm-project/commit/07bc98867d232add3bd823a7e6e0b1257ff836ca to collect more timing information:

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
  190.1413 ( 94.1%)   1.2036 ( 59.0%)  191.3449 ( 93.8%)  191.2808 ( 93.8%)  lto::backend opt
   6.3190 (  3.1%)   0.2526 ( 12.4%)   6.5716 (  3.2%)   6.2862 (  3.1%)  LTO::addRegularLTO
   4.5287 (  2.2%)   0.3791 ( 18.6%)   4.9079 (  2.4%)   5.1791 (  2.5%)  LTO::addThinLTO
   1.0622 (  0.5%)   0.2041 ( 10.0%)   1.2663 (  0.6%)   1.2656 (  0.6%)  lto::backend codegen
  202.0513 (100.0%)   2.0394 (100.0%)  204.0907 (100.0%)  204.0117 (100.0%)  Total

In other words: as expected, most of the regular LTO time is being spent in the optimizer, and the time spent in the backend is quite small.


https://reviews.llvm.org/D27324