[PATCH] D98263: [LoopInterchange] fix tightlyNested() in LoopInterchange legality

[Whitney Tsang via Phabricator via llvm-commits]

Whitney added a comment.

I am fine with this change now, but in the future we should try to

1. Use utilities in LoopNest as much as possible
2. Loosen the definition perfect loop nest in LoopNest
3. Make the transformation more generic to handle more cases, e.g. the newly added test `interchange_07`.



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Comment at: llvm/test/Transforms/LoopInterchange/not-interchanged-tightly-nested.ll:12
 @D = common global [100 x [100 x [100 x i32]]] zeroinitializer
+ at E = common global [100 x [100 x i64]] zeroinitializer
 
----------------
can we reuse the existing global arrays?


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Comment at: llvm/test/Transforms/LoopInterchange/not-interchanged-tightly-nested.ll:108
+
+;; The following Loop is not considered tightly nested and is not interchanged.
+; CHECK: Not interchanging loops. Cannot prove legality.
----------------
Please add comment for why it is not considered tightly nested. 
Is it because we expect the outer loop header to have a conditional branch?


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  https://reviews.llvm.org/D98263/new/

https://reviews.llvm.org/D98263