[llvm] [LV] Simplify epilogue VF selection by comparing against MaxTripCount (PR #186185)

[Hassnaa Hamdi via llvm-commits]

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@@ -10,7 +10,7 @@ target triple = "aarch64-unknown-linux-gnu"
 define void @foo(ptr noalias nocapture readonly %p, ptr noalias nocapture %q, i64 %len) #0 {
 ; CHECK-EPILOG:      vec.epilog.ph:
 ; CHECK-EPILOG:      vec.epilog.vector.body:
-; CHECK-EPILOG:        load <8 x i16>
+; CHECK-EPILOG:        load <4 x i16>
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hassnaaHamdi wrote:

Previously, when we can't calculate `MaxTripCount` -because rem iter is not fixed- we don't consider the cost of the remaining iterations when we compare between the most profitable VFs.
Now, we consider the `MaxTripCount` in all cases, that's why we chose VF of 4 whose cost is less.

https://github.com/llvm/llvm-project/pull/186185