Message-Id: <199610211814.OAA10948@delorie.com>
From: "Troy D. Van Horn" <trvanhor AT UCollege DOT edu>
Subject: Re: DJGPP V2.01 loop unrolling bug
To: dj AT delorie DOT com
Date: Mon, 21 Oct 1996 13:13:52 CDT
Cc: trvanhor AT SNOOPY DOT UCollege DOT edu, djgpp AT delorie DOT com
In-Reply-To: <199610211243.IAA17669@delorie.com>; from "DJ Delorie" at Oct 21, 96 8:43 am

 
> 
> > In which djgpp version was/is the loop unrolling bug supressed ?
> > I DID experience the bug using djgpp v2.0 and gcc 2.7.2.
> 
> It was supressed in the lib/specs file for djgpp v2.00 by adding
> -fno-strength-reduce to the C and C++ option sections:
> 
>    *cpp:
>    %{posix:-D_POSIX_SOURCE}
>    
>    *cc1:
>    -fno-strength-reduce
>    
>    *cc1plus:
>    -fno-strength-reduce
>    
>    *endfile:
> 
     Aren't loop unrolling and strenth reducing two different
optimizations? I was under the impression that 2.7.2.1 fixed the strenth-
reduce bug, and thus it is no longer disabled in the SPECS file, but that
2.7.2.1 totally disabled loop-unrolling because there is a place in the
Linux souce where a bug in this optimization could cause problems. At least
this is what I read from several postings from a newsgroup archive.

Troy...