Freeing memory for basic-blocks and edges

[Mike Stump]

On May 29, 2006, at 1:07 PM, sean yang wrote:
> For example, I know to allocate a chunk of memory to hold BB  
> information is done by "ggc_alloc_cleared()". But after a function  
> analysis/optimization is done, the memory should be freed.

   ggc_free (ptr);

can be used, but, if you use it, you have to be absolutely certain  
that there doesn't exist a reachable pointer to that memory,  
anywhere.  You must explicitly zero out any old pointers that pointed  
to the data, if those pointers would have been reachable otherwise.