Promote single-precision constants to REAL*8 constants.
All single-precision REAL constants are promoted to REAL*8. Double-precision (REAL*8) constants are not changed. This option only applies to constants. To promote both constants and variables, see –xtypemap=spec.
Use this option flag carefully. It could cause interface problems when a subroutine or function expecting a REAL*4 argument is called with a REAL*4 constant that gets promoted to REAL*8. It could also cause problems with programs reading unformatted data files written by an unformatted write with REAL*4 constants on the I/O list.