Last I played with 68k target gcc it was back in the 2.95 time. Back then gcc produced far worse code for 68k than SAS/C. I don't know if things has changed since, but in general -O2 with the flag specifying the CPU target (in this case -m68060) is usually the best choice.
I don't think it ever got a lot better in later versions. Last time I checked, it wouldn't even output scaled indexed addressing modes on 020+.
