[Bug bootstrap/44970] [4.6 regression] Revision 162270 failed to bootstrap

[bernds at gcc dot gnu dot org]

------- Comment #66 from bernds at gcc dot gnu dot org  2010-08-05 19:56 -------
(In reply to comment #57)

> Failure occurs for N = 0.  N = 1 compiles successfully.  Attached files.

Argh.  I seem to have swapped the logic of the dbg_cnt test.  Still, this
result appears useful.

I think initial RTL generation is fine, so it looks like my change has exposed
a latent bug.  What seems to happen is that some pass between expand and
combine lengthens the lifetime of register %r25, which holds an incoming
argument, so that it now crosses another call, which clobbers it.

This seems to happen in fwprop1, Cc Paolo.  I can't find any code in that pass
which tries to handle the situation.


-- 

bernds at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini at gnu dot org
         AssignedTo|bernds at gcc dot gnu dot   |bonzini at gnu dot org
                   |org                         |
             Status|ASSIGNED                    |UNCONFIRMED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44970