After you load all modules that you need, you can issue one of the following commands to have a list of the flags invoked by the appropriate compiler wrapper:

Cray PE wrappers 
cc -### -craype-verbose (or ftn or CC in place of cc)

or

cc -v -craype-verbose (or ftn or CC in place of cc)

Depending on the Programming Environment that you have loaded, you might need to give a filename on the command line. In general, an empty file with the correct extension will be enough (e.g.:foo.c, foo.f90 or foo.C).
For instance, the Cray compiler requires a filename with the option -v. Note that Cray wrappers provide the verbose flag  as well.

You can find more information on Cray compiler wrappers using the Linux man utility (man cc, man CC or man ftn).