[llvm] [LoopInterchange] Ignore the cost-model, force interchange if legal (PR #148858)

[Ryotaro Kasuga via llvm-commits]

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@@ -2,6 +2,10 @@
 ; RUN:     -pass-remarks-output=%t -disable-output
 ; RUN: FileCheck -input-file %t --check-prefix=PROFIT-CACHE %s
 
+; RUN: opt < %s -passes=loop-interchange -cache-line-size=64 \
+; RUN:     -pass-remarks-output=%t -disable-output -loop-interchange-force=true
+; RUN: FileCheck -input-file %t --check-prefix=PROFIT-VEC %s
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kasuga-fj wrote:

Could you please add another test case? Interchanging the loops in this test would be beneficial in perspective of vectorizatoin (i.e., `isProfitableForVectorization` returns true in this case) because it makes the innermost loop vectorizable. It would be ideal to add a case where interchanging is *definitely* unprofitable.

https://github.com/llvm/llvm-project/pull/148858