[llvm] [SLP]Initial support for copyable elements (PR #147366)

[Alexey Bataev via llvm-commits]

alexey-bataev wrote:

> > Fixed in [9a3aedb](https://github.com/llvm/llvm-project/commit/9a3aedb093008b55fa2018396cebb9b4606a7453)
> 
> It seems that fixed the [reduced test case](https://github.com/llvm/llvm-project/pull/147366#issuecomment-3255446568), but the [original reproducer](https://github.com/llvm/llvm-project/pull/147366#issuecomment-3253228267) with fwd_txfm.bc still fails as before.

Hmm, I tried the original reproducer and it passes too:
```
opt --passes=slp-vectorizer ./fwd_txfm.bc -S
```
Are you using some different flags/options?

https://github.com/llvm/llvm-project/pull/147366