[llvm] [SLP]Initial support for copyable elements (non-schedulable only) (PR #140279)

[Alexey Bataev via llvm-commits]

alexey-bataev wrote:

> A reduced C++ repro: [reduced.ii.gz](https://github.com/user-attachments/files/22383908/reduced.ii.gz)
> 
> ```
> $ build/bin/clang -cc1 -triple thumbv7-unknown-linux-android29 -Os -emit-obj -fprofile-instrument=llvm -vectorize-slp /tmp/reduced.ii
> ```
> 
> An IR reproducer based on the above: [reduced.ll.gz](https://github.com/user-attachments/files/22383919/reduced.ll.gz)
> 
> ```
> $ build/bin/opt -passes='default<O3>,slp-vectorizer' /tmp/reduced.ll -o - | build/bin/llc -filetype=asm -o -
> ```
> 
> Could you take a look?

I checked the original reproducer and the reduced one, used the debug version of the compiler. It does not look like SLP vectorizer is an issue here, even with the debug version of the compiler it passed fast. Looks like a backend issue, llc crashes after peephole-opt pass.   

https://github.com/llvm/llvm-project/pull/140279