On Tue, Mar 28, 2023 at 12:43:34PM +0000, Richard Biener wrote:
> When forwprop simplifies the CFG the 2nd order opportunities by
> exposed degenerate PHIs are not realized. The following improves
> this by properly tracking executable edges and thus handling this
> for non-cyclic CFGs at least.
>
> This avoids the bogus diagnostic reported for the testcase in this PR.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
>
> OK?
>
> Thanks,
> Richard.
>
> PR tree-optimization/107087
> * tree-ssa-forwprop.cc (pass_forwprop::execute): Track
> executable regions to avoid useless work and to better
> propagate degenerate PHIs.
>
> * testsuite/g++.dg/pr107087.C: New testcase.
LGTM.
Jakub
