[Bug rtl-optimization/118739] [15 Regression] wrong code at -O{s,3} with "-fno-tree-forwprop -fno-tree-vrp" on x86_64-linux-gnu since r15-268-g9dbff9c05520a7

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118739

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
So indeed the bisected revision just restored a previous change which was
originally done by Segher, r14-9692-g839bc42772ba7a, not sure if the issue
would reproduce between that and the initial reversion in
r14-9885-g109f1b28fc94c9

I don't know much of combines CCmode handling nor of CC vs CCNO to be of
any help here, but it does look like a genuine combine issue.