Re: [tree-ssa, RFC] CFG transparent RTL expansion

[Andrew MacLeod <amacleod at redhat dot com>]

On Fri, 2003-12-19 at 11:23, law@redhat.com wrote:
> In message <1071801428.21456.162.camel@p4>, Andrew MacLeod writes:
>  >This implements something which isnt actually used yet (ie, no
>  >collection emitted/done). If I read it correctly, just a proof of
>  >concept of a persistant CFG. So lets skip to how it would actually be
>  >used. And excuse my lackof knowledge about how gcc collects profile info
>  >:-)
> Another potential use would be to detect when the tree->rtl lowering
> process creates new blocks.  This _may_ be interesting in that it may
> be an indication that rather than a block-local CSE we may want to run
> something a little more extensive.  
> 
> If it's not obvious, I'm thinking about how we start trimming down the
> first stage RTL optimizers -- knowing if new blocks were created may be
> useful in determining which early RTL optimizers to run or what mode to
> run them in (block-local or extended-basic-blocks).

Yeah, Since the driving force behind keeping the CFG live through rtl is
to keep profiling information, we should try to list other things that
would either benefit from this, or be impacted so that we have multiple
reasons.

Andrew