[PATCH] D81236: Improve LegacyPassManager API to correctly report modified status

[serge via Phabricator via llvm-commits]

serge-sans-paille marked 2 inline comments as done.
serge-sans-paille added inline comments.


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Comment at: llvm/lib/Transforms/IPO/LoopExtractor.cpp:135
+  bool Changed = false;
+  LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>(F, &Changed).getLoopInfo();
 
----------------
ekatz wrote:
> jdoerfert wrote:
> > ekatz wrote:
> > > Maybe I am missing something, but isn't `LoopExtractor` dependent on `BreakCriticalEdges`? I mean, what are the transformations that the `LoopInfo` analysis depends on?
> > > what are the transformations that the LoopInfo analysis depends on?
> > 
> > No transformations:
> > 
> > ```
> >   void LoopInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {                                                                                                                                              
> >     AU.setPreservesAll();
> >     AU.addRequiredTransitive<DominatorTreeWrapperPass>();
> >   }
> >   
> > ```
> So why would the `Changed` ever be set to `true`?
It's set to True because of the on the fly pass evaluation: asking for `LoopInfo` triggers the whole dependencies, including `BreakCriticalEdges`. That's why the API change I propose only impacts on the fly passes.


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  https://reviews.llvm.org/D81236/new/

https://reviews.llvm.org/D81236