Broken private gcc port

[Paolo Bonzini]

Il 11/04/2013 14:57, Amir Gonnen ha scritto:
> Hi Paolo,
> 
> About 3 years ago I've sent a patch which was submitted by Kenneth
> Zadeck on revision 153924 (See
> http://gcc.gnu.org/ml/gcc-patches/2009-11/msg00232.html)
> 
> Recently we tried to update our gcc port from gcc-4.4 to gcc-4.8 and
> discovered that the same lines of code were changed, thus breaking our
> private port. The offending change was submitted by you on revision
> 163854 and I found no information about the reasons for it in the
> mailing lists.
> 
> I would appreciate if you could explain the rational for removing the
> previous handling of zero_extract(mem(...)) in the set dest, and why
> it was replaced by DF_REF_REG_USE while it looks to me as
> DF_REF_REG_MEM_STORE.

I think that was simply a cut-and-paste error.  Feel free to submit a
patch like this:

               {
                 if (GET_CODE (XEXP (dst,0)) == MEM)
                   df_uses_record (collection_rec, &XEXP (dst, 0),
-                                  DF_REF_REG_USE, bb, insn_info,
+                                  DF_REF_REG_MEM_STORE, bb, insn_info,
                                   flags);
                 else
                   df_uses_record (collection_rec, &XEXP (dst, 0),

I will review it happily.

Paolo

> There is a more general question here:
> I can, of course, change it locally and my port would work. But the
> change is not specific to my port, it's just that no other port
> currently has zero-extract with mem destination. But if there ever be
> one, it would benefit from my change. (and of course I'll benefit from
> it when I update gcc version again, or if our private port ever become
> public).
> 
> So the question is - should I bother send such patches if no other
> port is currently affected by them?  (when the changes are still
> general in their nature)
> 
> Thanks,
> 
> Amir
>