[Bug tree-optimization/126771] sub-optimal bool pattern for comparison converted to integer

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126771

--- Comment #2 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
>       /* We may directly use cond with narrowed type to avoid multiple cond
>          exprs with following result packing and perform single cond with
>          packed mask instead.  In case of widening we better make cond first
>          and then extract results.  */
>       if (TYPE_MODE (type) == TYPE_MODE (TREE_TYPE (lhs)))
>         type = TREE_TYPE (lhs);
> 
> ISTR on aarch64 SVE masks are still "unpacked", 

Sorta, we also support computed masks.

Computed masks, are from SVE2p1 and SME2's multi-vector operations.
These instead of having a xx bits per lane, use a specific encoding
to say how many registers they cover and what the lanes of these
registers are See [1] "SME2 Multi-vector predication"

We don't support these in the vectorizer yet but is on our roadmap.

[1]
https://developer.arm.com/community/arm-community-blogs/b/architectures-and-processors-blog/posts/part4-arm-sme2-introduction