On Wed, Sep 9, 2015 at 8:07 AM, Mathieu Malaterre <malat@xxxxxxxxxx> wrote: > Manuel, > > On Tue, Sep 8, 2015 at 11:31 PM, Manuel López-Ibáñez > <lopezibanez@xxxxxxxxx> 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 >> >> (If there is something that is not explained there, it would be better to >> expand the answer rather than reply here with bits of info.) > > Thanks for the link. However -in my case- the compile option > `-fexcess-precision=standard` does produce the same code as > `-ffloat-store`. At least for Meant to say `does not produce` > [...] > double div; /* OPJ_FLOAT64 */ > div = dd / dr; > if (div >= thresh) > [...] > > Is there a longer description for `-fexcess-precision=standard` which > explains case of failures ? >From a clean debian/sid 32bits chroot I can no longer reproduce this. In summary: 1. removed -ffast-math 2. add -std=c99 3. Change the code for an explicit storage of division (div = dd / dr) => issue solved ! Thx
