https://gcc.gnu.org/bugzilla/show_bug.cgi?id=14708
--- Comment #9 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> --- An update after all these years: As Joseph S. Myers said in the gcc-help list in February 2005, "even -ffloat-store only deals with assignment, not casts": https://gcc.gnu.org/pipermail/gcc-help/2005-February/051031.html So, -ffloat-store did not really help to solve the issue, though those aware of it could replace casts by intermediate variables to ensure a conversion to the target precision with -ffloat-store. Rather ugly. Since then, the -fexcess-precision option has been added[*] for GCC 4.5 and should probably be recommended as a replacement for -ffloat-store. Or is there still any reason to use -ffloat-store? [*] PR323 comment 123 by Joseph S. Myers (November 2008).