Re: [avr-libc-dev] New release?

[Dmitry K.]

On Thursday 29 November 2007 02:16, Anatoly Sokolov wrote:
[...]
> I suggest to set up the minimal required version of GCC as 4.2.
> It will allow:
>
> 1. To remove check of new devices which are already supported in the GCC
> 4.2 from 'configure.ac' file.
>
> 2. To remove avr25 divices from 'AVR12_DEV_INFO' in 'gen-avr-lib-tree.sh'
> file, and do not build 'crt*' files for this devices twice.
>
> 3. Do not define '__AVR_HAVE_MOVW__', '__AVR_HAVE_LPMX__' and
> '__AVR_HAVE_MUL__' macros in avr-libc.

I object.
The listed items have no value for users and are not burdensome
for developers of Avr-libc.

On the contrary, I would warn against rash transition
to version 4.2.

GCC 4.2 is too agressive in optimization. For example,
the next function is translated as infinite loop (-Os):
   void foo (void)
   {
      int i;
      for (i = 1; i >= 0; i++) bar ();
   }
More, common options '-W -Wall' do NOT type any warnings!

Simultaneously quality of a code concedes not only to
branches 3.3 and 3.4, but even concedes to a branch 4.1.
For example, Avr-libc's sscanf("1.2345","%e",&x) takes
3886 bytes of flash and 140 bytes of stack with 4.2.2.
Above branch (4.1.2) uses only 3802 bytes of flash and
128 bytes of stack.

Dmitry.