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Re: Do C++ signed types have modulo semantics?

From: Steven Bosscher <stevenb at suse dot de>
To: Daniel Berlin <dberlin at dberlin dot org>
Cc: Ulrich Weigand <uweigand at de dot ibm dot com>, 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: Wed, 29 Jun 2005 20:32:16 +0200
Subject: Re: Do C++ signed types have modulo semantics?
References: <200506281202.j5SC27s7024579@53v30g15.boeblingen.de.ibm.com> <200506291846.34864.stevenb@suse.de> <1120068079.7612.31.camel@linux-009002219098.watson.ibm.com>

On Wednesday 29 June 2005 20:01, Daniel Berlin wrote:
> So i would advise anyone arguing against turning on -fwrapv simply
> because it doesn't seem to hurt us at O2.

wtf, "doesn't seem to hurt us at -O2".  Look again at the 64 bits
numbers!  Losing 5% on the fp benchmarks is a serious regression.
Even without exercising the heavy-ammo loop optimizers, -fwrapv is
a serious performance-hurter.

Gr.
Steven

Follow-Ups:
- Re: Do C++ signed types have modulo semantics?
  - From: Robert Dewar

References:
- Re: Do C++ signed types have modulo semantics?
  - From: Ulrich Weigand
- Re: Do C++ signed types have modulo semantics?
  - From: Steven Bosscher
- Re: Do C++ signed types have modulo semantics?
  - From: Daniel Berlin

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