https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110891
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #3) > One thing I noticed (I don't know if causes the missed optimization) is that > we have before PRE: > ``` > <bb 4> [local count: 1073531371]: > if (a.0_1 != 0) > goto <bb 6>; [50.00%] > else > goto <bb 5>; [50.00%] > > <bb 5> [local count: 536765686]: > if (_28 == &d) > goto <bb 9>; [30.00%] > else > goto <bb 7>; [70.00%] > > <bb 6> [local count: 536765685]: > if (_28 == &d) > goto <bb 9>; [30.00%] > else > goto <bb 7>; [70.00%] > ``` > Which obvious should just be `if (_28 == &d) goto bb9; else goto bb7;` and > not check `a.0_1` at all. I wonder if ifcombine could optimize that instead of requiring PRE. I think that might even fix the issue too.
