How can I get the dump file which is in SSA form ?

[Qiang Huang]

   I used the command bellow:

        gcc -fdump-tree-ssa hello.c

   to dump the file in SSA form. However, I can't find the file in the
directory.It seems that the file wasn't dumped at all.

   I tried this in different version of GCC,but it was the same in the
GCC4.1.1,4.2.3 and 4.3.0.

   I wonder that if someone could tell me the exact reason~Thanks a lot~