[llvm] [Scalarizer] Fix oob crash on insertelement with PHI (PR #228460)

[Kyuwon Cho via llvm-commits]

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@@ -0,0 +1,20 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt %s -passes='function(scalarizer<load-store>,dce)' -S | FileCheck %s
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ChoKyuWon wrote:

I copied the constant-extractelement/extractelemental.ll.
https://github.com/llvm/llvm-project/blob/cb24ba3b310f7a97803fd2e975b62113efab93bc/llvm/test/Transforms/Scalarizer/constant-insertelement.ll#L2
https://github.com/llvm/llvm-project/blob/cb24ba3b310f7a97803fd2e975b62113efab93bc/llvm/test/Transforms/Scalarizer/constant-extractelement.ll#L2

They also handle the OOB extract/insert and seem to be similar issues, so I follow the old test cases.

https://github.com/llvm/llvm-project/pull/228460