Jakub Jelinek <ja...@redhat.com> writes:
> On Wed, Feb 28, 2018 at 02:20:27PM +0000, Richard Sandiford wrote:
>> GCC 6 and 7 would vectorise:
>>
>> void
>> f (unsigned long incx, unsigned long incy,
>> float *restrict dx, float *restrict dy)
>> {
>> unsigned long ix = 0, iy = 0;
>> for (unsigned long i = 0; i < 512; ++i)
>> {
>> dy[iy] += dx[ix];
>> ix += incx;
>> iy += incy;
>> }
>> }
>>
>> without first proving that incy is nonzero. This is a regression from
>> GCC 5. It was fixed on trunk in r223486, which versioned the loop based
>
> Are you sure about the revision? This one is from 2015 and so should be in
> all of GCC 6/7/8.
Oops, that was when the bug started. r256644 was the fix.
