https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111522
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |WAITING Ever confirmed|0 |1 Last reconfirmed| |2023-09-21 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- I think this is just broken code. It does: #define HWY_BEFORE_NAMESPACE() \ HWY_PUSH_ATTRIBUTES("altivec,vsx,power8-vector" \ ",cpu=power10") But does not do a pop before the main function. And then you are testing on power8 which obvious does not have all of the instructions as power10 ... Why it works without -flto is just pure accident not using the instructions that are not in power8. Anyways I suspect this is too much reduced testcase. So you might need to provide the original one.