https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80928
--- Comment #30 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #29)
> So a testcase for missed outer loop induction SLP (and nested cycle SLP) is
> for example
>
> int a[1024];
> void foo (unsigned n)
> {
> for (int i = 0; i < 1020; i += 4)
> {
> int suma = a[i];
> int sumb = a[i+1];
> int sumc = a[i+2];
> int sumd = a[i+3];
> for (unsigned j = 0; j < 17; ++j)
> {
> suma = (suma ^ i) + 1;
> sumb = (sumb ^ i) + 2;
> sumc = (sumc ^ i) + 3;
> sumd = (sumd ^ i) + 4;
> }
> a[i] = suma;
> a[i+1] = sumb;
> a[i+2] = sumc;
> a[i+3] = sumd;
> }
> }
Actually this is still not an inner loop induction in outer loop vectorization.
But missed nested cycle SLP handling. I have a patch for this in testing.
