CC 5.5 compiler flag to issue 64bit porting warnings on sparc-solaris

Hello,

We have a full working product which runs successfully on 32bit sparc-solaris m/c with CC 5.5 compiler
We are porting our 32 bit application to 64bit. That is we are migrating from 32bit to 64bit on sparc solaris machine
So we need compiler flag which issues 64 bit porting issues from exsting 32bit application.
We tried with CC 5.5 compiler options like -xarch=v9, and -xport64=full to get porting issues. But we are not getting any porting issues or warnings.
Please tell us some option to get porting warnings or issues.
We are using CC 5.5 compiler on sparc-solaris-sun m/c.

Thanks
shobha