[PATCH] D25682: [LoopUnroll] Keep the loop test only on the first iteration of max-or-zero loops

[John Brawn via llvm-commits]

john.brawn added inline comments.


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Comment at: lib/Analysis/ScalarEvolution.cpp:5741
         MustExitMaxBECount = EL.MaxNotTaken;
-      else {
+        MustExitMaxOrZero = EL.MaxOrZero;
+      } else {
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sbaranga wrote:
> Does this work with more than one loop exit and with predicated loop exits?
> 
> I'm not certain this would hold if we have at least one loop exit that doesn't dominate the latch, given the very strict definition (the backedge gets taken exactly 0 or MaxNotTaken times).
That's handled down on line 5759 - MaxOrZero is set to false on loops with more than one exit.


Repository:
  rL LLVM

https://reviews.llvm.org/D25682