https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90774
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-06-07
Component|middle-end |tree-optimization
Ever confirmed|0 |1
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
The veclower pass already does this but is appearantly confused by missed
association:
<bb 2> [local count: 1073741825]:
_18 = k_17(D) / 2;
_1 = {_18, _18, _18, _18};
_2 = _1 + num_19(D);
_21 = p_20(D) * 6234;
_3 = {_21, _21, _21, _21};
the + num_19(D) done early makes it a vector result early. Associating
that in a different way would help.
So as Andrew says this is a reassoc heuristic issue.
Doing
return num + (1 + k / 2 + p * 6234 + 75 * h + j / 3452 + 53 * w + x / 820 +
4 * u + y + 25 + 829 / 3 * (3452/3));
also does what you want this.
