Actually, for all the perl work I've done on Solaris, I've used the gcc-built perl and the gcc suite from sunfreeware. Much easier to get real work done with that.
At least the last time I compared them, gcc produced code that was quite noticeably slower. Now this doesn't matter if you're writing your code in perl (if speed were all important you'd use C or FORTRAN or some related evil), but it does matter for some XS modules.