Re: redirect_edge_and_branch questions

[Andrew MacLeod <amacleod at redhat dot com>]

On Fri, 2004-10-01 at 17:49, Zdenek Dvorak wrote:
> Hello,
> 
> > Perhaps it would make sense to have function that takes list of
> > incomming edges to given basic block and create empty basic block before
> > redirecting the selected edges into it.  This operatinon should be
> > usefull at least for creating loop preheaders.
> 
> and its name is "make_forwarder_block" :-)

So I have converted over to make_forwarder_block, but I have a different
problem now.

make_forwarder_block eventually calls ssa_redirect_edge(). Ive removed
all the PHI nodes, so the PHI_NODE code doesnt do anything, but the
function has the annoying side effect of clearing the PENDING_STMT list
in that case. (it returns the arguemnts of the PHI in the stmt list I
guess. No PHIs, no stmts)

So what happens is that I redirect a bunch of edges to the new forwarder
block, and any edges which aren't redirected get their PENDING_STMT list
cleared.  I might be able to work around this, but it is a tad annoying.

When do we tell the cfg routines that we are not in SSA mode any more?
Do they differentiate between SSA and trees at all?  

Andrew