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Re: Loop unrolling
- To: egcs-patches at cygnus dot com, egcs at cygnus dot com, pfeifer at dbai dot tuwien dot ac dot at
- Subject: Re: Loop unrolling
- From: mrs at wrs dot com (Mike Stump)
- Date: Mon, 1 Jun 1998 16:32:24 -0700
- Cc: tim at wagner dot princeton dot edu
> Date: Mon, 1 Jun 1998 12:57:21 +0200 (MET DST)
> From: Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at>
> To: egcs-patches@cygnus.com, egcs@cygnus.com
> cc: Tim Hollebeek <tim@wagner.princeton.edu>
> As a matter of fact, is there still any strong reason not to delete
> empty loops in general?
I don't think we should.
> > Morover, with @samp{-funroll-loops} small ``empty'' loops indeed are
> > removed, so the current behavior is both sub-optimal and inconsistent
> > and may well change in the future.
I don't think this should go in the docs. I think it is a bug in the
unroller that gcc optimizes away an empty loop. I think this should
be fixed. I think the docs can admit the current bug, but should not
call it anything but a bug.