[llvm] [SLP]Improve findReusedOrderedScalars and graph rotation. (PR #77529)

[Alexey Bataev via llvm-commits]

alexey-bataev wrote:

> [reduced3.zip](https://github.com/llvm/llvm-project/files/14450664/reduced3.zip)
> 
> please see the reproducer attached.
> 
> the difference I see after compiling with `-O3` is:
> 
> ```
>    %5 = select <4 x i1> %2, <4 x float> %3, <4 x float> %4
> -  %6 = shufflevector <4 x float> %5, <4 x float> poison, <4 x i32> <i32 2, i32 0, i32 3, i32 1>
> +  %6 = shufflevector <4 x float> %5, <4 x float> poison, <4 x i32> <i32 1, i32 2, i32 3, i32 0>
>    store <4 x float> %6, ptr %tmp.i.i4, align 8
> ```

Must be fixed by 45d82f33af9334907dde39cc69921c679299114e

https://github.com/llvm/llvm-project/pull/77529