gcc 3.4.0 m68k-elf generates illegal code for ColdFire (maybe a fix)

[Bernardo Innocenti]

peter@lasergraph-dsp.de wrote:
> Dear gcc gurus,
> 
> since no one wants to handle the old illegal code generation issue (it
> seems it existed since 2002), I tried to find it myself. I might have
> found it:
> In reload.c (find_reloads) a force reload needs IMHO to be forced not
> only for memory operands, but also for pseudo registers, which also
> reside in memory.
> 
> Can someone with deeper understanding of gcc verify that this assumption
> is correct and does not break any other code?

I'm not qualified to review your patch, sorry.  I could run
regression tests for your patch.  Is there a PR already on file?

> Here is a patch:
> 
> -------------------------------------------------------------------------------
> 2004-05-27  Peter Jakubek  <peter@laseranimation.com>
> 
>     * reload.c (find_reloads): force reload for pseudo registers on big
>     endian machines.
> 
> diff -ru gcc.orig/gcc/reload.c gcc/gcc/reload.c
> --- gcc.orig/gcc/reload.c    2004-03-10 02:51:01.000000000 +0100
> +++ gcc/gcc/reload.c    2004-05-27 13:07:32.828125000 +0200
> @@ -2947,7 +2947,7 @@
>                  < BIGGEST_ALIGNMENT)
>                 && (GET_MODE_SIZE (operand_mode[i])
>                     > GET_MODE_SIZE (GET_MODE (operand))))
> -              || (GET_CODE (operand) == MEM && BYTES_BIG_ENDIAN)
> +              || (BYTES_BIG_ENDIAN)
>  #ifdef LOAD_EXTEND_OP
>                || (GET_MODE_SIZE (operand_mode[i]) <= UNITS_PER_WORD
>                    && (GET_MODE_SIZE (GET_MODE (operand))

By removing the "GET_CODE (operand) == MEM" check
you're maybe underspecifying the condition.  The operand
may also be an immediate or a hard register.

Maybe this?

   || BYTES_BIG_ENDIAN
      && (GET_CODE (operand) == MEM)
          || (GET_CODE(operand) == REG
              && REGNO(operand) >= FIRST_PSEUDO_REGISTER))


> I also added my original patch for m68k_output_mi_thunk to fix the invalid
> code that was genrated on ColdFire for thunks:
> 
> 2004-05-27  Peter Jakubek  <peter@laseranimation.com>
> 
>     * config/m68k/m68k.c (m68k_output_mi_thunk): correct code generated
>       for ColdFire.

A slightly different version of this patch just went in CVS today.

It was credited to Peter Barada, but now I wonder wether you've
both developed the same patch independently or I should add your
name in the ChangeLog entry.

-- 
  // Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/  http://www.develer.com/