[PATCH] D94717: [LoopNest] Consider loop nest with inner loop guard using outer loop induction variable to be perfect

[Bardia Mahjour via Phabricator via llvm-commits]

bmahjour requested changes to this revision.
bmahjour added inline comments.
This revision now requires changes to proceed.


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Comment at: llvm/lib/Analysis/LoopInfo.cpp:408
+      return GuardBI;
+  } while ((USBB = USBB->getUniqueSuccessor()));
+
----------------
apart from checking that the control flow can be simplified, we also need to check to make sure that the chain of BBs don't contain unsafe instructions (or at least check that they are empty).


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Comment at: llvm/test/Analysis/LoopNestAnalysis/imperfectnest.ll:428
-
-; Test an imperfect loop nest of the form:
-;   for (int i = 0; i < nx; ++i)
----------------
Whitney wrote:
> This test case should be considered as imperfect, as the user branch is not the inner loop guard.
the user branch is behaving as a guard so we can allow it per the current definition of a loop guard.


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https://reviews.llvm.org/D94717