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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
From: |
Gabriel Dos Reis |
Subject: |
Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..." |
Date: |
29 Dec 2006 17:40:11 +0100 |
Andrew Pinski <address@hidden> writes:
| >
| > Paul Eggert <address@hidden> writes:
| >
| > > * NEWS: AC_PROG_CC, AC_PROG_CXX, and AC_PROG_OBJC now take an
| > > optional second argument specifying the default optimization
| > > options for GCC. These optimizations now default to "-O2 -fwrapv"
| > > instead of to "-O2". This partly attacks the problem reported by
| > > Ralf Wildenhues in
| > > <http://lists.gnu.org/archive/html/bug-gnulib/2006-12/msg00084.html>
| > > and in <http://gcc.gnu.org/ml/gcc/2006-12/msg00459.html>.
| >
| > Does anybody think that Paul's proposed patch to autoconf would be
| > better than changing VRP?
|
| I think both ways are incorrect way forward.
| What about coding the loops like:
|
| if (sizeof(time_t) == sizeof(unsigned int))
| {
| // do loop using unsigned int
| // convert to time_t and then see if an overflow happened
| }
| //etc. for the other type
Yuck.
If the above is the only without Autoconf change, I would highly
recommend Autoconf change if GCC optimizers highly value benchmarks
over running real world code.
-- Gaby
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", (continued)
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paolo Bonzini, 2006/12/20
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paul Eggert, 2006/12/21
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paolo Bonzini, 2006/12/21
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paul Eggert, 2006/12/21
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paolo Bonzini, 2006/12/21
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paul Eggert, 2006/12/21
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Russ Allbery, 2006/12/21
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paul Eggert, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Ian Lance Taylor, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Andrew Pinski, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...",
Gabriel Dos Reis <=
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Andrew Pinski, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gabriel Dos Reis, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Thomas Neumann, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Andrew Pinski, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gabriel Dos Reis, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Florian Weimer, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Daniel Jacobowitz, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Richard Guenther, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Paul Eggert, 2006/12/29
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Richard Kenner, 2006/12/30