https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113455
--- Comment #3 from Joseph S. Myers <jsm28 at gcc dot gnu.org> --- If you're linking with the version of the DFP arithmetic functions (__bid_adddd3 etc.) in libdfp rather than the libgcc version - check the link order carefully to make sure the right version is linked in - and they're not respecting the rounding mode, that would be a libdfp issue, not a GCC one. If you're doing arithmetic with constant operands, it might be folded at compile time; make sure you're using -frounding-math to avoid that.