[llvm] [X86][BF16] Support INSERT_SUBVECTOR and CONCAT_VECTORS (PR #76485)

[Simon Pilgrim via llvm-commits]

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@@ -372,31 +372,11 @@ entry:
 
 ;; FIXME: This should generate the same output as above, but let's fix the crash first.
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RKSimon wrote:

Remove FIXME?

https://github.com/llvm/llvm-project/pull/76485