[llvm] Patch tryCanonicalizeStructToVector to handle split slice tails (PR #201434)

[Yaxun Liu via llvm-commits]

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@@ -5131,20 +5131,27 @@ static FixedVectorType *tryCanonicalizeStructToVector(StructType *STy,
   if (StructSize != VectorSize)
     return nullptr;
 
-  for (const Slice &S : P) {
+  auto IsMemIntrinsicOnlySlice = [](const Slice &S) {
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yxsamliu wrote:

This helper also accepts dead/no-use slices plus lifetime/debug intrinsics, not only MemIntrinsic users. Maybe name it something like `IsAllowedStructToVectorSlice` or `IsIgnorableOrMemIntrinsicSlice` to make the policy clearer.

https://github.com/llvm/llvm-project/pull/201434