[PATCH] D86156: [BFI] Preserve BFI information through loop passes via VH callbacks inside LoopStandardAnalysisResults

Alina Sbirlea via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Wed Aug 26 16:54:50 PDT 2020


asbirlea added inline comments.


================
Comment at: llvm/lib/Passes/PassBuilder.cpp:522
   FPM.addPass(createFunctionToLoopPassAdaptor(
-      std::move(LPM2), /*UseMemorySSA=*/false, DebugLogging));
+      std::move(LPM2), /*UseMemorySSA=*/false, /*UseBlockFrequencyInfo=*/true,
+      DebugLogging));
----------------
It doesn't look like `UseBlockFrequencyInfo` is used for LPM2 here and below. Would it make sense to set it to `false` at this point?



================
Comment at: llvm/test/Other/pass-pipelines.ll:57
 ; CHECK-O2: Loop Pass Manager
-; CHECK-O2-NOT: Manager
+; Requiring block frequency for LICM will place ICM and rotation under separate Loop Pass Manager
 ; FIXME: We shouldn't be pulling out to simplify-cfg and instcombine and
----------------
Add `; CHECK-O2: Loop Pass Manager` along with this comment.


Please consider if splitting the loop pass pipeline has any effects on optimizations. This is for the legacyPM only, so those who switched to the newPM will not be affected.
The solution may be to mark the analyses preserved in loop unswitch.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D86156/new/

https://reviews.llvm.org/D86156



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