Re: [Qemu-devel] Re: [PATCH 1/5] Fix i386 Host

[Johannes Schindelin]

Hi,

On Fri, 18 Jan 2008, Michael Matz wrote:

> On Fri, 18 Jan 2008, Johannes Schindelin wrote:
> 
> > > But I'm not talking about the clobber list at all.  I reacted to the 
> > > first mail forwarded to me, which was a question specifically about 
> > > the hunk adding the "q" constraint, whose purpose I explained.  Are 
> > > you now also asking about the changes regarding %ecx and the clobber 
> > > list?
> > 
> > Okay, look, I do not have enough time to fix it myself.  But there 
> > _is_ a breakage with gcc 3.4.2 on MinGW.  If that is not fixed, I will 
> > openly oppose that patch going into CVS.
> 
> That's fine and is why I sent a test patch which might fix the breakage 
> when applied on top of the constraint patch.
> 
> > All I tried was to get an understanding why the current patch "Fix 
> > i386" (which is still misnamed) broke on MinGW.
> 
> Well, I can tell you why, but it doesn't help you: the 3.4.2 compiler 
> has different deficiencies in reload than the 4.x line of compilers.  
> To make the whole thingy work on all compilers trying and testing is 
> required to avoid all these different deficiencies.  My patch is partly 
> real bug fixes (the "q" constraint part for instance) and partly changes 
> helping to lessen the register pressure which reload needs to fix (the 
> %ecx thingy for instance).  Both of these might expose the bugs in 
> 3.4.2, in which case we need to hack around those as well.  That's what 
> I tried to do with the patch from 
> http://article.gmane.org/gmane.comp.emulators.qemu/22762 , but it needs 
> of course testing by someone who actually uses 3.4.2.

I just downloaded it, and tested it on MinGW with 3.4.2, and I still get 
the "can't find register in class `Q_REGS´ while reloading `asm´" error.

Ciao,
Dscho