[Bug tree-optimization/38723] default definitions not in avail_out

["dberlin at dberlin dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from dberlin at gcc dot gnu dot org  2009-01-04 22:35 -------
Subject: Re:  New: default definitions not in avail_out

At one time we pretended they were defined in the entry block, and
IIRC, it worked out okay.
Dunno what happened to this :)


On Sun, Jan 4, 2009 at 1:40 PM, rguenth at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
> FRE does not optimize
>
> int i;
> int foo (void)
> {
>  int j;
>  i = j;
>  return i;
> }
>
> because j_1(D) is never in AVAIL_OUT, so we do not find a leader for it.
>
> We can fix this by either pretending used default definitions are defined
> in the entry block or by treating default definitions the same as constants
> during elimination.
>
> Danny?
>
>
> --
>           Summary: default definitions not in avail_out
>           Product: gcc
>           Version: 4.4.0
>            Status: UNCONFIRMED
>          Keywords: missed-optimization
>          Severity: enhancement
>          Priority: P3
>         Component: tree-optimization
>        AssignedTo: unassigned at gcc dot gnu dot org
>        ReportedBy: rguenth at gcc dot gnu dot org
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38723
>
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-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38723