https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87079
sandra at gcc dot gnu.org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2018-11-02 CC| |sandra at gcc dot gnu.org Assignee|unassigned at gcc dot gnu.org |sandra at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from sandra at gcc dot gnu.org --- This looks like a problem with the nios2 instruction costs. Things are going wrong in expand_widening_mult (in expmed.c); compiling with -O2 takes the expand_binop path at the end to use the provided umulsidi3 expander, but with -Os it thinks the expand_mult_const path is better. I'll try to poke at this some more and come up with a patch.