[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
From: |
Andrew Pinski |
Subject: |
Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..." |
Date: |
Sat, 30 Dec 2006 19:42:05 -0500 (EST) |
>
> Andrew Pinski wrote:
>
> >> -fwrapv-in-all-cases-except-loop-bounds
> >
> >
> > Again, please don't this the default for Fortran as integer
> > overflow has been undefined since at least 1977 so I don't think
> > it is a good idea for GCC in general anyways as evidence of Fortran.
> >
> > -- Pinski
>
> Well the question is whether the optimization buys anything
> in practice for other than the loop bound case, I am guessing
> it does not, and if that is the case there is an argument
> for uniformity.
It does buy you something for code like:
if (a - 10 < 20)
that might show up in a hot loop. So we are able to remove one extra
instruction.
In fact I think this code does show up in GCC and most likely other places.
Oh and it is a very simple optimization that I added and I don't want it
removed for C
or Fortran or C++ for that matter.
Thanks,
Andrew Pinski
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", (continued)
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gabriel Dos Reis, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Richard Guenther, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gabriel Dos Reis, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Richard Guenther, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gabriel Dos Reis, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Robert Dewar, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gabriel Dos Reis, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Andrew Pinski, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gabriel Dos Reis, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Robert Dewar, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...",
Andrew Pinski <=
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Robert Dewar, 2006/12/30
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Vincent Lefevre, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Robert Dewar, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Richard Kenner, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Vincent Lefevre, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Robert Dewar, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Vincent Lefevre, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Robert Dewar, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Vincent Lefevre, 2006/12/31
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ...", Gerald Pfeifer, 2006/12/31