possible bug on PPC/ GNU/LINUX

[Daniel Diaz]

Hi all,

obviously my command -line is false I used in fact -ffixed-15 (I simply tried 
before an impossible register to see if egcs produced a warning: no :-)).

However even with -ffixed-15 I have the same problem. 

>If I am not mistaken, he should not have a compatibility problem if he
>uses a register which is normally saved by function calls.  Any
>function compiled with -ffixed-r15 -should- not touch it except in the
>desired capacity; any function compiled without it should save/restore
>it on exit.

I expected such a behavior. When I recompile my whole Prolog system (more 
than 60000 of C code) I have no problem using r14 and r15 with -O but I have 
when no using -O. I then suspected a bug. To use global registers I generally 
use nonvolatile registers since each function modifying it should restore it. 
so I can safely call ANY library function (respecting the ABI) and for my own 
code gcc/egcs correctly handles these registers. When it cannot do this a 
warning (something like global clobbered register I don't remember well) is 
emitted.

Since I implement a compiler it is a big advantage to map the registers of my 
abstract machine to real registers... 

Thanks to all people developping and improving gcc...


-- 
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                 Daniel Diaz
University of Paris 1      INRIA Rocquencourt
   75013 Paris           78153 Le Chesnay Cedex
     FRANCE                     FRANCE
        email: Daniel.Diaz@inria.fr
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