http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60206
--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- On Fri, 14 Feb 2014, pinskia at gcc dot gnu.org wrote: > I think the real issue __FP_FRAC_SUB_4 needs to be fixed not to use inline-asm > but normal C code. The normal C code should be able to produce as good as the > inline-asm code now too. Does GCC do a good job of detecting add-with-carry and subtract-with-borrow patterns (i.e. detecting the comparison that corresponds to the carry flag and its use in a subsequent operation)? (The Clang __builtin_addc* / __builtin_subc* functions might also be a useful addition for this sort of purpose.)