This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: [tree-ssa] DCE and conditionals
- From: law at redhat dot com
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: Andrew MacLeod <amacleod at redhat dot com>, gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Mon, 05 May 2003 14:54:57 -0600
- Subject: Re: [tree-ssa] DCE and conditionals
- Reply-to: law at redhat dot com
In message <20030505201105.GA28303@tornado.toronto.redhat.com>, Diego Novillo w
rites:
>On Mon, May 05, 2003 at 08:31:47AM -0400, Andrew MacLeod wrote:
>After fixing the flow graph linearizer, this should be converted
>into:
>
> if ((void)0)
> (void)0;
> else
> (void)0;
> lab:
> a_5 = PHI <a_1, a_0, a_4>
>
>Note how the COND_EXPR is only kept because it provides the
>structure needed to feed that PHI node. If all 'a's coalesce
>together, then SSA->normal could remove the empty skeleton for
>the if().
The useless crud zapper already catches this (yes, I'm finally
back from our little adventure in sin city).
jeff