[Bug tree-optimization/126963] [17 Regression] 6% slowdown of lbm on Zen5 since r17-2817-g5e45cc08f3bbbf

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126963

--- Comment #3 from rguenther at suse dot de <rguenther at suse dot de> ---
On Thu, 20 Aug 2026, jmelcr at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126963
> 
> --- Comment #2 from Josef Melcr <jmelcr at gcc dot gnu.org> ---
> Yes, I verified the bisection before submitting the bug and ran it again just
> now, it does slow down. This lbm graph seems to be stable, though lbm can be
> pretty noisy. Could just be random changes slowing it down I guess?

Possibly.  At least it does hint at that the particular change of
copy-propagation causes downstream code generation changes (the
copy would not have prevailed for long even before the change).