why basic block 0 and 1 not in output graph

[Ian Lance Taylor]

tys lefering <twlevo@gmail.com> writes:

> using gcc-4.3.2 and tested gcc-4.5 development snapshot noticed that using
> 'gcc -da -dv test.c' to generate vcg graph output files these files do not have
> "basic block 0" and "basic block 1" in the vcg graph output.
>
> is this intended and what exactly represent block 0 and block 1 ?

Basic block 0 is the entry block.  Basic block 1 is the exit block.
Neither block contains any statements.  gcc used to use -1 and -2 for
these, but that was changed to simplify some data structures.

Ian