[gentoo-dev] GCC 4.8 unmasking

[gentoo-dev] GCC 4.8 unmasking

[Ryan Hill]

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I don't see any reason to keep this masked other than bug #416069, which
needs to be fixed anyways.  How does Friday sound?

https://bugs.gentoo.org/416069  xorg-2.eclass: add --disable-selective-werror to configure
https://bugs.gentoo.org/461954  GCC 4.8 porting



-- 
Ryan Hill                        psn: dirtyepic_sk
   gcc-porting/toolchain/wxwidgets @ gentoo.org

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Re: [gentoo-dev] GCC 4.8 unmasking

[Luca Barbato]

On 13/08/13 03:41, Ryan Hill wrote:
> I don't see any reason to keep this masked other than bug #416069, which
> needs to be fixed anyways.  How does Friday sound?
> 
> https://bugs.gentoo.org/416069  xorg-2.eclass: add --disable-selective-werror to configure
> https://bugs.gentoo.org/461954  GCC 4.8 porting

gcc-4.8 can miscompile libc

http://gcc.gnu.org/bugzilla//show_bug.cgi?id=56888

We should make sure we do not get bitten by this.

lu

[gentoo-dev] Re: GCC 4.8 unmasking

[Ryan Hill]

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On Tue, 13 Aug 2013 07:13:13 +0200
Luca Barbato <lu_zero@gentoo.org> wrote:

> On 13/08/13 03:41, Ryan Hill wrote:
> > I don't see any reason to keep this masked other than bug #416069, which
> > needs to be fixed anyways.  How does Friday sound?
> > 
> > https://bugs.gentoo.org/416069  xorg-2.eclass: add
> > --disable-selective-werror to configure https://bugs.gentoo.org/461954  GCC
> > 4.8 porting
> 
> gcc-4.8 can miscompile libc
> 
> http://gcc.gnu.org/bugzilla//show_bug.cgi?id=56888
> 
> We should make sure we do not get bitten by this.

We don't build glibc with -O3.  Other libc's should either not use -O3 or
use -fno-tree-loop-distribute-patterns where applicable.


-- 
Ryan Hill                        psn: dirtyepic_sk
   gcc-porting/toolchain/wxwidgets @ gentoo.org

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Re: [gentoo-dev] Re: GCC 4.8 unmasking

[Luca Barbato]

On 14/08/13 01:40, Ryan Hill wrote:
> On Tue, 13 Aug 2013 07:13:13 +0200
> Luca Barbato <lu_zero@gentoo.org> wrote:
> 
>> On 13/08/13 03:41, Ryan Hill wrote:
>>> I don't see any reason to keep this masked other than bug #416069, which
>>> needs to be fixed anyways.  How does Friday sound?
>>>
>>> https://bugs.gentoo.org/416069  xorg-2.eclass: add
>>> --disable-selective-werror to configure https://bugs.gentoo.org/461954  GCC
>>> 4.8 porting
>>
>> gcc-4.8 can miscompile libc
>>
>> http://gcc.gnu.org/bugzilla//show_bug.cgi?id=56888
>>
>> We should make sure we do not get bitten by this.
> 
> We don't build glibc with -O3.  Other libc's should either not use -O3 or
> use -fno-tree-loop-distribute-patterns where applicable.
> 

On certain arches the memcpy tranformation happens even on lower
optimization levels or so I saw reported.


lu

[gentoo-dev] Re: GCC 4.8 unmasking

[Ryan Hill]

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On Wed, 14 Aug 2013 17:56:42 +0200
Luca Barbato <lu_zero@gentoo.org> wrote:

> > We don't build glibc with -O3.  Other libc's should either not use -O3 or
> > use -fno-tree-loop-distribute-patterns where applicable.
> 
> On certain arches the memcpy tranformation happens even on lower
> optimization levels or so I saw reported.

I don't see how that could happen without -ftree-loop-distribute-patterns.  Can
you dig up a link?


-- 
Ryan Hill                        psn: dirtyepic_sk
   gcc-porting/toolchain/wxwidgets @ gentoo.org

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