Suddenly I need GMP and MPFR?

Suddenly I need GMP and MPFR?

[Rick Mann]

I tried to build (an AVR target) of GCC 4.3.0 on Mac OS X 10.5.2  
today, and it stopped with the following:

> checking for correct version of gmp.h... no
> configure: error: Building GCC requires GMP 4.1+ and MPFR 2.3.0+.

This is surprising, since I was able to build GCC-4.1.2 and even 4.2.1  
without it. Is this a new requirement?

Thanks for the education...

-- 
Rick

Re: Suddenly I need GMP and MPFR?

[Brian Dessent]

Rick Mann wrote:

> This is surprising, since I was able to build GCC-4.1.2 and even 4.2.1
> without it. Is this a new requirement?

See <http://gcc.gnu.org/gcc-4.3/changes.html>.  gcc 4.2.x only required
them if you enabled gfortran, but 4.3.0 and on require them
unconditionally.

Brian

Re: Suddenly I need GMP and MPFR?

[Rick Mann]

On Apr 18, 2008, at 1:01 PM, Brian Dessent wrote:

> See <http://gcc.gnu.org/gcc-4.3/changes.html>.  gcc 4.2.x only  
> required
> them if you enabled gfortran, but 4.3.0 and on require them
> unconditionally.


Thank you; I should've checked that first.

I'm not sure I understand how GCC uses these libraries. If I'm cross- 
compiling for AVR, shouldn't the library  be built on AVR? This  
creates a new chicken-and-egg problem, doesn't it?

If I build GMP/MPFR for Mac OS X using Xcode (assuming it'll even  
build; apparently there are issues with Apple's GCC), that will build  
libraries that execute on OS X/i386. Is that the only capacity in  
which GMP/MPFR are used by GCC? Or does it attempt to generate target  
code that uses it?

Thanks!

-- 
Rick

Re: Suddenly I need GMP and MPFR?

[David Daney]

Rick Mann wrote:
> 
> On Apr 18, 2008, at 1:01 PM, Brian Dessent wrote:
> 
>> See <http://gcc.gnu.org/gcc-4.3/changes.html>.  gcc 4.2.x only required
>> them if you enabled gfortran, but 4.3.0 and on require them
>> unconditionally.
> 
> 
> Thank you; I should've checked that first.
> 
> I'm not sure I understand how GCC uses these libraries. If I'm 
> cross-compiling for AVR, shouldn't the library  be built on AVR? This 
> creates a new chicken-and-egg problem, doesn't it?

No, the libraries are only used by the compiler proper.  They allow the 
compiler to do constant folding at compile time and get the same answer 
that the processor would have gotten.

> 
> If I build GMP/MPFR for Mac OS X using Xcode (assuming it'll even build; 
> apparently there are issues with Apple's GCC), that will build libraries 
> that execute on OS X/i386. Is that the only capacity in which GMP/MPFR 
> are used by GCC? 

Yes.


> Or does it attempt to generate target code that uses it?

No.

Re: Suddenly I need GMP and MPFR?

[Rick Mann]

On Apr 18, 2008, at 1:18 PM, David Daney wrote:

> Rick Mann wrote:
>> Thank you; I should've checked that first.
>> I'm not sure I understand how GCC uses these libraries. If I'm  
>> cross-compiling for AVR, shouldn't the library  be built on AVR?  
>> This creates a new chicken-and-egg problem, doesn't it?
>
> No, the libraries are only used by the compiler proper.  They allow  
> the compiler to do constant folding at compile time and get the same  
> answer that the processor would have gotten.
>
>> If I build GMP/MPFR for Mac OS X using Xcode (assuming it'll even  
>> build; apparently there are issues with Apple's GCC), that will  
>> build libraries that execute on OS X/i386. Is that the only  
>> capacity in which GMP/MPFR are used by GCC?
>
> Yes.
>
>
>> Or does it attempt to generate target code that uses it?
>
> No.


Thanks!

-- 
Rick