Re: [PATCH 14/16] tree-ssa-loop-niter.c: use gimple_phi in a few places

[Andrew MacLeod <amacleod at redhat dot com>]

On 12/13/2013 10:58 AM, David Malcolm wrote:
>   {
>     gimple stmt = SSA_NAME_DEF_STMT (x);
> @@ -2162,7 +2162,7 @@ chain_of_csts_start (struct loop *loop, tree x)
>     if (gimple_code (stmt) == GIMPLE_PHI)
>       {
>         if (bb == loop->header)
> -	return stmt;
> +	return stmt->as_a_gimple_phi ();
>   
>         return NULL;
>       }
> @@ -2195,10 +2195,10 @@ chain_of_csts_start (struct loop *loop, tree x)
>   
>      If such phi node exists, it is returned, otherwise NULL is returned.  */

I dislike separating the checking of gimple_code () and the following 
as_a.   I rather envisioned this sort of thing as being more of an 
abstraction improvement if we never have to check gimple_code()...   
Then you are also less locked into a specific implementation.

So something more like:

if (gimple_phi phi = stmt->dyncast_gimple_phi ())
  {
     if (bb == loop->header)
       return phi;
  }


IMO anyway...

Andrew