Re: SSA for Trees - PRE implementation

[Daniel Berlin <dberlin at dberlin dot org>]

On Jan 8, 2004, at 2:06 PM, Sidney Bennett wrote:

> I see some work has been done on using SSA in GCC.  According to the 
> GCC
> internals manual, only constant propagation and dead-code elimination 
> are
> implemented, but http://gcc.gnu.org/projects/tree-ssa includes a 
> longer list
> of SSA passes, including Partial Redundancy Elimination.  Is an SSA 
> PRE pass
> complete or available?

Yes.

It's in the file tree-ssa-pre.c

It does load PRE and regular PRE, but not the strength reduction 
extensions yet.

>  Is anyone working on it?
Yes. (Me)
>   I've recently attempted an
> SSA PRE implementation based on the Kennedy, et.al. paper and met with
> significant difficulties.

Non-surprising :P

>  I am curious if others have found success or if
> they have found similar problems.
>
> Sid