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

[Hans Wennborg via llvm-commits]

zmodem wrote:

> Are you using some different flags/options?

I ran it like this: `opt -O3 /tmp/fwd_txfm.bc -o /dev/null`

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