[PATCH] D124119: [InstCombine] Combine instructions of type or/and where AND masks can be combined.

Mon May 30 05:44:52 PDT 2022

alexfh added a comment.

Hi Biplob,
This commit has increased compilation time of certain translation units by a large factor. It raised from ~7s to at least 20 minutes. -ftime-report shows that the code previously put already quite a heavy load on InstCombinePass:

  Total Execution Time: 6.0698 seconds (6.0699 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   2.0465 ( 34.4%)   0.0269 ( 23.8%)   2.0734 ( 34.2%)   2.0734 ( 34.2%)  InstCombinePass
   1.4016 ( 23.5%)   0.0360 ( 31.8%)   1.4376 ( 23.7%)   1.4376 ( 23.7%)  ModuleInlinerWrapperPass
   1.3901 ( 23.3%)   0.0360 ( 31.8%)   1.4261 ( 23.5%)   1.4262 ( 23.5%)  DevirtSCCRepeatedPass
   0.3090 (  5.2%)   0.0001 (  0.1%)   0.3091 (  5.1%)   0.3091 (  5.1%)  SROAPass

However after this change some parts of the algorithm may have become exponential. At least I haven't seen the compilation finish yet. We're trying to come up with an isolated test case, but please consider reverting the commit while working on a fix. Thanks!

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124119/new/

https://reviews.llvm.org/D124119