Re: m68k bootstrapping broken

[Gunther Nikl <gni at gecko dot de>]

On Wed, Jan 14, 2004 at 05:14:05PM +0100, Andreas Schwab wrote:
> Gunther Nikl <gni@gecko.de> writes:
> 
> >   IMHO, if there is a bug with CC handling it _should_ also be visible
> >   with a cross-compiler, shouldn't it? If GCC(cc1) generates wrong code
> >   then there must be a change in the cc1 executable (besides the patch
> >   place!). Maybe I am wrong about it but the CC problem I ran into
> >   was observable with a cross-compiler and the generated code after
> >   the fix was different compared to the code before the fix. That doesn't
> >   seem to be the case with the output_move_const_into_data_reg() patch.
> 
> What did you test exactly?

  [First, I noticed that it was stated the bug does only show up on a native
   bootstrap. However, you also stated you had a miscompiled compiler created
   by a ppc->m68k cross-compiler.]

  I used a checkout from 12.1.2004. I built a i386->m68k cross compiler
  for m68k-amigaos and then used this cross-compiler to built a native
  compiler for m68k-amigaos. Then I installed your patch to
  m68k.c/output_move_const_into_data_reg and created a new cross-compiler.
  This cross-compiler was then used to compile a new native compiler.
  Then I compared the objects in gcc/ for the native compiler versions
  created by the unpatched and patched cross-compilers. There was no
  difference except in m68k.o/output_move_const_into_data_reg (because
  of your patch). IMHO, there _should_ be differences in other objects if
  your patch would really fix a miscompilation. If there is no difference
  then your patch doesn't have any effect, does it?

  Maybe I am totally off-track with my reasoning.

  Gunther