https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88842
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-01-15
Component|other |tree-optimization
Ever confirmed|0 |1
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
void foo(int a, int b, int c, int d, int e, int *res) {
res[0] = (e * a) * d;
res[1] = (e * b) * d;
res[2] = (e * c) * d;
}
associating (e * d) allows CSE. Only possible when there's no overflow
(-fwrapv or unsigned types).
The issue is that reassoc is a "local" optimization, associating single
chains rather than looking at multiple chains at once.
And of course reassoc isn't "integrated" with CSE.
