MPC required in one week.

MPC required in one week.

[Kaveh R. GHAZI]

The patch which makes the MPC library a hard requirement for GCC
bootstrapping has been approved today.  As promised, I'll wait one week
before applying it to give everyone a chance to install MPC on their
systems.

You can download mpc-0.8 from either of these two locations:
ftp://gcc.gnu.org/pub/gcc/infrastructure/mpc-0.8.tar.gz
http://www.multiprecision.org/mpc/download/mpc-0.8.tar.gz

The current GCC infrastructure supports both in-tree builds as well as the
expected --with-mpc= configure flag.  If you're installing MPC in a
non-standard directory, I recommend building it with --disable-shared to
avoid needing to set LD_LIBRARY_PATH when running GCC.  (The same issue
arises with gmp/mpfr.)

Of course, let me know of any problems.

		--Kaveh

Re: MPC required in one week.

[Michael Witten]

On Mon, Nov 30, 2009 at 12:04 AM, Kaveh R. GHAZI <ghazi@caip.rutgers.edu> wrote:
> The patch which makes the MPC library a hard requirement for GCC
> bootstrapping has been approved today.

Out of curiosity and ignorance: Why, specifically, is MPC going to be
a hard requirement?

On the prerequisites page, MPC is currently described with: "Having
this library will enable additional optimizations on complex numbers."

Does that mean that such optimizations are now an important
requirement? or is MPC being used for something else?

Re: MPC required in one week.

[Kaveh R. Ghazi]

From: "Michael Witten" <mfwitten@gmail.com>

> On Mon, Nov 30, 2009 at 12:04 AM, Kaveh R. GHAZI <ghazi@caip.rutgers.edu> 
> wrote:
>> The patch which makes the MPC library a hard requirement for GCC
>> bootstrapping has been approved today.
>
> Out of curiosity and ignorance: Why, specifically, is MPC going to be
> a hard requirement?

Some of the benefits are noted here:

http://gcc.gnu.org/gcc-4.5/changes.html#mpcopts

Re: MPC required in one week.

[Paolo Bonzini]

On 11/30/2009 09:47 PM, Michael Witten wrote:
> On Mon, Nov 30, 2009 at 12:04 AM, Kaveh R. GHAZI<ghazi@caip.rutgers.edu>  wrote:
>> The patch which makes the MPC library a hard requirement for GCC
>> bootstrapping has been approved today.
>
> Out of curiosity and ignorance: Why, specifically, is MPC going to be
> a hard requirement?
>
> On the prerequisites page, MPC is currently described with: "Having
> this library will enable additional optimizations on complex numbers."
>
> Does that mean that such optimizations are now an important
> requirement? or is MPC being used for something else?

They are a requirement for Fortran, but it's (much) simpler to do them 
for all front-ends.

Paolo

Re: MPC required in one week.

[Silvius Rus]

On Tue, Dec 1, 2009 at 2:25 AM, Paolo Bonzini <bonzini@gnu.org> wrote:
>
> On 11/30/2009 09:47 PM, Michael Witten wrote:
>>
>> On Mon, Nov 30, 2009 at 12:04 AM, Kaveh R. GHAZI<ghazi@caip.rutgers.edu>  wrote:
>>>
>>> The patch which makes the MPC library a hard requirement for GCC
>>> bootstrapping has been approved today.
>>
>> Out of curiosity and ignorance: Why, specifically, is MPC going to be
>> a hard requirement?
>>
>> On the prerequisites page, MPC is currently described with: "Having
>> this library will enable additional optimizations on complex numbers."
>>
>> Does that mean that such optimizations are now an important
>> requirement? or is MPC being used for something else?
>
> They are a requirement for Fortran, but it's (much) simpler to do them for all front-ends.
>
> Paolo
>

On the flip side, it's not necessarily easy to get it to work.  On my
build system, apt-get doesn't find it.  Downloading and installing the
.deb manually triggers 3 missing deps.
ftp://gcc.gnu.org/pub/gcc/infrastructure/ is unresponsive, so I had to
look around for the source.  Installing from source fails with a
libgmp abi message during configuration, so now I need to fiddle with
it.  Like many, I don't use fortran much, so this is pure overhead at
this point.

It could be just that my build system is such that it's more difficult
to bring in this change than is in the average case.  I'm not arguing
against change, especially when it brings improved performance, but I
think it's worth reinforcing that bringing in a library dependence is
not free.  (Looking at this issue oblivious of the maintenance and
development burden, it would have been nice to have a transitional
--no-mpc configure option.)

Silvius

Re: MPC required in one week.

[Jie Zhang]

On 12/27/2009 03:05 PM, Silvius Rus wrote:
> On the flip side, it's not necessarily easy to get it to work.  On my
> build system, apt-get doesn't find it.  Downloading and installing the
> .deb manually triggers 3 missing deps.

apt-get install libmpc-dev

libmpc-dev is already in squeeze and sid if you are using Debian.


Jie

Re: MPC required in one week.

[Jie Zhang]

On 12/01/2009 06:25 PM, Paolo Bonzini wrote:
> On 11/30/2009 09:47 PM, Michael Witten wrote:
>> On Mon, Nov 30, 2009 at 12:04 AM, Kaveh R.
>> GHAZI<ghazi@caip.rutgers.edu> wrote:
>>> The patch which makes the MPC library a hard requirement for GCC
>>> bootstrapping has been approved today.
>>
>> Out of curiosity and ignorance: Why, specifically, is MPC going to be
>> a hard requirement?
>>
>> On the prerequisites page, MPC is currently described with: "Having
>> this library will enable additional optimizations on complex numbers."
>>
>> Does that mean that such optimizations are now an important
>> requirement? or is MPC being used for something else?
>
> They are a requirement for Fortran, but it's (much) simpler to do them
> for all front-ends.
>
Actually the bug mentioned in 4.5 release page under MPC is a C bug.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30789

So it seems not only just for Fortran.


Jie