[PATCH] combine: Special handling for conditional refs when creating log links

[Steven Bosscher]

On Fri, May 7, 2010 at 7:13 PM, Bernd Schmidt <bernds@codesourcery.com> wrote:
> On 05/07/2010 05:22 PM, Steven Bosscher wrote:
>> On Fri, May 7, 2010 at 5:00 PM, Michael Matz <matz@suse.de> wrote:
>
>>>  flow.c did handle conditional execution, hence also conditional
>>> liveness, also of pseudos.  So if anything, the above is a new restriction
>>> since introduction of the DF framework.
>>
>> FUD.
>
> Fact, actually.  We did have code in flow.c to track liveness in the
> presence of COND_EXEC exactly, and it appears to have been lost entirely
> when df was introduced.

It depends on what you mean with exactly. I suppose you mean per insn,
like in df_simulate_one_insn_backwards. That was apparently lost, yes.
I don't know why. But DF will handle COND_EXEC insns with pseudos if
asked to. That part is not lost.

>  I've recently discovered this when looking at
> peephole2; see my recent mail about this.

I assumed you are referring to
http://gcc.gnu.org/ml/gcc-patches/2010-04/msg01395.html.

Ciao!
Steven