[PATCH] D60832: [MemorySSA] LCSSA preserves MemorySSA.

Thu Apr 18 16:46:28 PDT 2019

asbirlea marked an inline comment as done.
asbirlea added inline comments.

================
Comment at: lib/Transforms/Utils/LCSSA.cpp:490-491
   PA.preserve<ScalarEvolutionAnalysis>();
+  // In the new pass manager, LCSSA must mark the AAManager as preserved too, in
+  // order to correctly preserve MemorySSA.
+  PA.preserve<MemorySSAAnalysis>();
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chandlerc wrote:
> Should the AA manager just preserve itself instead so that this isn't so confusing for users?
Sure?  I though it was stateless already, so preserved by default, but I'm unclear how to mark that.

This got me *very* confused in the first iteration of this patch, when I noticed a new AAManager being built for the LoopPassManager. Why would that happen?

Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D60832/new/

https://reviews.llvm.org/D60832