-mfpmath=387 used on x86_64 is supposed to force gcc to use 387 for floating point{math. However, even with the option, gcc generates cvtts{s,d}2* instead of fistp* for floating-point to integer conversion.
This makes a difference if/when the extra precision of 387 makes difference to the conversion - which -mfpmath=387 is supposed to prevent. -- Summary: -mfpmath=387 doesn't use fistp for double-to-integer conversion Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: seongbae dot park at gmail dot com GCC host triplet: i686-unknown-linux-gnu GCC target triplet: x86_64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29337