https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92712
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Known to work| |7.5.0
Keywords| |missed-optimization
Last reconfirmed| |2019-11-28
CC| |rguenth at gcc dot gnu.org
Ever confirmed|0 |1
Summary|Performance regression with |[8/9/10 Regression]
|assumed values |Performance regression with
| |assumed values
Target Milestone|--- |8.4
Known to fail| |9.2.0
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
This is final value replacement becoming more correct wrt undefined overflow I
guess.
final value replacement:
x_6 = PHI <x_5(3)>
with expr: (const int) ((unsigned int) t_1(D) + 4294967295) * v_3(D) + v_3(D)
final stmt:
x_6 = _14 + v_3(D);
Here we fail to optimize (t - 1)*v + v to t * v. Not sure how the t >= 0
assert helped but we likely get rid of that earlier and earlier.
