-fprecision=p

Initialize floating-point precision mode on x86.

x86:77

p is either single, double, or extended.

Initialize the floating-point hardware precision mode on x86 platforms to single, double, or extended. Compile the main program with this option. (See the Floating-Point chapter of the Fortran Programming Guide.)

The default, when -fprecision is not specified, is -fprecision=extended.