[PATCH] D143631: [LTO] Don't let InstCombine re-sink the vastly more expensive fdiv

[Nikita Popov via Phabricator via llvm-commits]

nikic added reviewers: fhahn, dmgreen.
nikic added a comment.

Compile-time: http://llvm-compile-time-tracker.com/compare.php?from=6c5ba7cddfa2210e9ddb12ab6f016b84db9a8b23&to=ef44d3f482b284ee11a5335d8c714f7eceb3dea7&stat=instructions:u

Post-link numbers are:

  kc.link 	 	30147M 	30326M (+0.59%)
  sqlite3.link 	 	40914M 	41303M (+0.95%)
  consumer-typeset.link 	36935M 	37405M (+1.27%)
  bullet.link 	 	27582M 	27914M (+1.20%)
  tramp3d-v4.link 	137504M 139271M (+1.29%)
  pairlocalalign.link 	19476M 	19686M (+1.08%)
  clamscan.link 	 	56907M 	57439M (+0.93%)
  lencod.link 	 	102321M 102803M (+0.47%)
  SPASS.link 	 	51517M 	52669M (+2.24%)
  7zip-benchmark.link 	106003M 105851M (-0.14%)

Despite that, I'm on board with this change.



================
Comment at: llvm/lib/Passes/PassBuilderPipelines.cpp:1259
+               /*AllowSpeculation=*/true),
+      /*UseMemorySSA=*/true, /*UseBlockFrequencyInfo=*/true));
+
----------------
UseBlockFrequencyInfo should stay false.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D143631/new/

https://reviews.llvm.org/D143631