On 2015.09.08 at 23:31 +0200, Manuel López-Ibáñez wrote: > On 08/09/15 22:05, Mathieu Malaterre wrote: > > > > Ok, I think I understand now. -O0 did produce code that is compatible > > with -ffloat-store. However I am still required to use -ffloat-store > > (explicitly) for any other optimization (at least required with -O2 in > > my case). > > You are not required to use -ffloat-store, neither is -ffloat-store guaranteed > to work. Please read https://gcc.gnu.org/wiki/FAQ#PR323 And please note that he whole issue has nothing to do with gcc. See e.g.: http://stackoverflow.com/questions/31973139/gcc-m32-option-changes-floating-point-rounding-when-not-running-valgrind for a similar example. -- Markus
