http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58234
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- First FD_ZERO comes from glibc so this is not a GCC bug. Second this question should go to ICC rather than GCC since it is their compiler which is causing the complaint in the end rather than GCC. And third the inline-asm is correct to begin with as both rcx and rdi are changed by "rep;stosl/stosq" so having an output constraints is correct; otherwise the compiler could decide to reuse those values that were in them.