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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."

From: Bernd Schmidt <bernds_cb1 at t-online dot de>
To: Paul Eggert <eggert at CS dot UCLA dot EDU>
Cc: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>, autoconf-patches at gnu dot org, bug-gnulib at gnu dot org, gcc at gcc dot gnu dot org
Date: Sat, 30 Dec 2006 11:39:40 +0100
Subject: Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
References: <200612291732.kBTHWNkC024013@localhost.localdomain> <871wmipecd.fsf@mid.deneb.enyo.de> <20061229215223.GA25381@nevyn.them.org> <84fc9c000612291357x7c6568ecvb19bdb94d923d137@mail.gmail.com> <87odpmkzqs.fsf@penguin.cs.ucla.edu> <10612300026.AA05792@vlsi1.ultra.nyu.edu> <87fyaykx4b.fsf@penguin.cs.ucla.edu>

Paul Eggert wrote:

(2) In the current SPEC, how many programs benefit from undefined overflow
semantics and how much does each benefit?


Those questions are more for the opponents of -fwrapv, so
I'll let them answer them.  But why are they relevant?

It's relevant in a "did my system just become 50% slower because of a change in autoconf defaults" sort of way.

(3) How many programs are known to rely on wrap semantics?  For each:
  (a) How hard was it to determine there was a problem with that assumption?

I'm not sure what you're asking for here.

Actual data, rather than handwaving. Which programs are affected? Show us all the broken code that you are actually aware of. You are making this out to be a huge problem, so let's see why.

Bernd

References:
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Andrew Pinski
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Florian Weimer
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Daniel Jacobowitz
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Richard Guenther
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Paul Eggert
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Richard Kenner
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Paul Eggert

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