This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Do C++ signed types have modulo semantics?
- From: Steven Bosscher <stevenb at suse dot de>
- To: Ulrich Weigand <uweigand at de dot ibm dot com>
- Cc: gcc at gcc dot gnu dot org, Robert Dewar <dewar at adacore dot com>, Mark Mitchell <mark at codesourcery dot com>, Michael Veksler <VEKSLER at il dot ibm dot com>, Paul Koning <pkoning at equallogic dot com>, gdr at integrable-solutions dot net, nathan at codesourcery dot com
- Date: Tue, 28 Jun 2005 14:09:02 +0200
- Subject: Re: Do C++ signed types have modulo semantics?
- References: <200506281202.j5SC27s7024579@53v30g15.boeblingen.de.ibm.com>
On Tuesday 28 June 2005 14:02, Ulrich Weigand wrote:
> Steven Bosscher wrote:
> > Anyway, I've started a SPEC run with "-O2" vs. "-O2 -fwrapv". Let's see
> > how big the damage would be ;-)
>
> Please make sure to include a 64-bit target, where it actually makes any
> difference. (I recall performance degradations of 20-30% in some
> SPECfp cases from getting induction variable reduction wrong ...)
Yeah, I'm testing on an AMD64 box, both 64 bits and 32 bits.
Gr.
Steven