https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118687
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> --- If you want the compiler to synthetize the constant, why don't you use asm ("" : "=r" (ret) : "0" (0x0123456789abcdefull)); (of course in this case why not just return 0x0123456789abcdefull). In any case, ask for the constant to be in either some register or a selected specific register.