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

[bernds at codesourcery dot com]

------- Comment #73 from bernds at codesourcery dot com  2010-08-06 10:27 -------
Subject: Re:  [4.6 regression] Revision 162270 failed
 to bootstrap

On 08/06/2010 12:00 PM, bonzini at gnu dot org wrote:
> ------- Comment #72 from bonzini at gnu dot org  2010-08-06 10:00 -------
> No, why is there no def for r25 _where it is clobbered_?

There is.  The problem seems to be that we first propagate into insn 15,
which then looks like

(insn 15 14 16 3 (set (reg:DI 67 [ obj.8+-4 ])
        (sign_extend:DI (reg:SI 25 %r25 [ obj ])))
../../gcc/gcc/cfg.c:1211 139 {extendsidi2}
     (expr_list:REG_DEAD (reg/v:DI 74 [ obj+-4 ])
        (nil)))

and from there, we propagate into another insn.  However, at this point,
insn 15 has no uses associated with it, so all_uses_available_at returns
true without doing anything.


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