[llvm] [InstCombine] Fold `umax/umin(nuw_shl(z, x), nuw_shl(z, y)) -> nuw_shl(z, umax/umin(x, y))` and `umax/umin(nuw_shl(x, z), nuw_shl(y, z)) -> nuw_shl(umax/umin(x, y), z)` (PR #131076)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw requested changes to this pull request.

After this patch, InstCombine cannot fold the following pattern: https://godbolt.org/z/eadW6T8nb
```
define i8 @umin_of_add_nuw_r(i8 %a, i8 %b, i8 %c) {
  %add1 = add nuw i8 %b, %a
  %add2 = add nuw i8 %a, %c
  %min = call i8 @llvm.umin.i8(i8 %add1, i8 %add2)
  ret i8 %min
}
```

https://github.com/llvm/llvm-project/pull/131076