On Mon, Jul 27, 2026 at 6:15 PM Tamar Christina <[email protected]> wrote:
>
> The 07/27/2026 08:21, H.J. Lu wrote:
> > When the size of record or array is smaller than the target alignment,
> > don't over align them and set DR_TARGET_ALIGNMENT to the reduced target
> > alignment. If the natural alignment isn't lower than the reduced target
> > alignment, set base_misaligned to false.
> >
>
> Definitely need Richi's input here, but I think changing DR_TARGET_ALIGNMENT
> overloads this value which is used for more than the alignment of the object
> but also used for this like peeling and versioning and runtime checks, so
> changing it to something that's less than
> targetm.vectorize.preferred_vector_alignment
We ask the backend for preferred vector parameters without
checking the data size. We shouldn't even try 32-byte vector
on a 20-byte data. Can we pass the data size to the backend
when asking for preferred vector parameters?
> could cause problems.
>
> I think your original patch was more correct, i.e. just refuse to change the
> alignment in vect_compute_data_ref_alignment and so leave it unaligned.
>
> Was there a specific reason you went with this approach instead?
>
I got GCC testsuite regressions with the other approach using
make check RUNTESTFLAGS="--target_board='unix{-m32\
-march=x86-64-v4,-march=x86-64-v4}'"
--
H.J.
