With a recent gfortran, the following compiles, but generates the wrong results:
! http://gcc.gnu.org/ml/fortran/2005-04/msg00139.html real*8 :: a integer*8 :: i1,i2 a=.4999999999999999444888487687421729788184165954589843750_8 i2=NINT(.4999999999999999444888487687421729788184165954589843750_8) i1=NINT(a) ! 0.499999999999999944488848768742 0 0 write(6,'(F40.30,2I2)') a,i1,i2 IF (i1.NE.i2) CALL ABORT() a=4503599627370497.0_8 i1=NINT(a,KIND=8) i2=NINT(4503599627370497.0_8,KIND=8) ! 4503599627370497 4503599627370497 4503599627370497 write(6,*) 4503599627370497_8,i1,i2 IF (i1.NE.i2) CALL ABORT() END -- Summary: wrong code generated with gfortran Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jv244 at cam dot ac dot uk http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31202