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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
- From: Paul Eggert <eggert at CS dot UCLA dot EDU>
- To: Thorsten Glaser <tg at mirbsd dot de>
- Cc: autoconf-patches at gnu dot org, bug-gnulib at gnu dot org, gcc at gcc dot gnu dot org
- Date: Wed, 17 Jan 2007 00:24:52 -0800
- Subject: Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
- References: <200612300047.kBU0lFwk014817@localhost.localdomain> <87bqlmkui3.fsf@penguin.cs.ucla.edu> <10612300508.AA08474@vlsi1.ultra.nyu.edu> <87psa1izpc.fsf@penguin.cs.ucla.edu> <45963E6D.5070203@t-online.de> <10612301301.AA14129@vlsi1.ultra.nyu.edu> <871wmht4ab.fsf@penguin.cs.ucla.edu> <Pine.BSM.4.64L.0701161826250.25568@herc.mirbsd.org>
Thorsten Glaser <tg@mirbsd.de> writes:
> Paul Eggert dixit:
>
>> [â] gcc -O2 makes no promises without
>> -fwrapv.
>
> gcc -O1 -fwrapv even doesn't work correctly for gcc3,
> and gcc2 and gcc <3.3(?) don't even have -fwrapv:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30477
The latter would not be a problem, since Autoconf would try -fwrapv on
a test module before using it to compile a real module.
Do you have a test case illustrating the gcc3 bug? If so,
perhaps Autoconf could include that in its test of -fwrapv.