[PATCH] D93686: [LoopUnroll] Fix a crash

[Serguei Katkov via Phabricator via llvm-commits]

skatkov marked 2 inline comments as done.
skatkov added inline comments.


================
Comment at: llvm/lib/Transforms/Utils/LoopUnroll.cpp:404
+        dbgs() << "Can't unroll; a conditional latch must exit the loop");
+    return LoopUnrollResult::Unmodified;
+  }
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fhahn wrote:
> Does this need updating? At this point, we could have peeled the loop and thus change it I think. 
> 
> Also, by moving the early exit to after peeling, we now expose more cases to peeling. Can peeling handle the case of the early exit properly?
I'm sorry I do not follow what you mean here. Could you please elaborate on what should be changed?

The only earlier return we do not do now for peeling is
!LatchBI || (LatchBI->isConditional() && !LatchIsExiting)

Loop peeling has its own guard canPeel() which is also triggered in computePeelCount.
Peeling guard requires that latch is a conditional exiting block.
So nothing new we are introducing.


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  https://reviews.llvm.org/D93686/new/

https://reviews.llvm.org/D93686