Re: m68k bootstrapping broken

[Gunther Nikl <gni at gecko dot de>]

On Tue, Jan 13, 2004 at 10:57:29PM +0100, Bernardo Innocenti wrote:
> Gunther Nikl wrote:
> 
> >>I checked again, SWAP will also produce a correct cc, here is an
> >>updated patch.
> >
> >  I just built a native compiler for m68k-amigaos with a cross-compiler
> >  that had the updated patch applied. No objects in gcc/ except m68k.o
> >  differed. Is that a good or bad sign?
> 
> You mean "differed between your previous build and the build with
> Andreas patch"?

  Yes. I don't do native bootstraps because I don't have enough time and
  patience for them ;)

> Richard Zidlicky reported a difference in "make compare" which you
> can't do unless you perform a full staged bootstrap with a native
> compiler.

  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.

> >  Flags used to build the native compiler:
> >    CFLAGS=-O2
> >    XCFLAGS=-m68060 -fomit-frame-pointer -fno-reorder-blocks
> 
> By the way, do you also agree that -fomit-frame-pointer is always
> a win on m68k?

  Code size decreases and one more spare register. I have always used
  -fomit-frame-pointer. I have no timings what it really buys.

> AFAIK, gdb handles it correctly and all -fomit-frame-pointer bugs should
> have been fixed.
>
> I'll run a testsuite with -fomit-frame-pointer enabled to make
> sure it doesn't break anything.
> 
> My proposal is to switch m68k to imply -fomit-frame-pointer with
> -O.  Of course, I think we're too late for 3.4, so it will have
> to be postponed even if we all agree.

  Enabling -fomit-frame-pointer by default with -O would be OK with me.

  Gunther