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Re: Propagate profile counts after switch case expansion (issue5896043)


On Mon, Apr 9, 2012 at 2:33 PM, Easwaran Raman <> wrote:
> On Sun, Mar 25, 2012 at 9:40 PM, Easwaran Raman <> wrote:
>> On Sun, Mar 25, 2012 at 12:22 PM, Jan Hubicka <> wrote:
>>>> This patch propagates execution count of thee case labels of a
>>>> switch-case statement after its expansion. Bootstraps and all
>>>> tests pass. OK for trunk?
>>> Hi,
>>> while this is resonable thing to do, I belive it would make most sense
>>> to make switch lowering at gimple level: i.e. reorganize the existing
>>> code to produce gimple statement and change expansion code to produce
>>> tablejump from every gimple switch statement that was left in the
>>> code.
>>> This would be both cleaner and would allow gimple optimizers to improve the
>>> generated code. Incrementally it would also allow us to improve switch exansion
>>> that is quite baroque and not realy producing very good code in some common
>>> cases.
>>> If you would be interested working on this (i.e. reorganizing the expansion
>>> code to produce gimple), I would be very happy. If not, I can review the
>>> profile updating part for mainline, since in any case this is desriable thing
>>> to do.
>> I am planning to explore improvements to switch expansion (peeling
>> some cases and using jump tables for the rest, for example) and I
>> think the reorganization you suggest is the right way to do such
>> improvements. But until I can spend time on it and get it done, I
>> would like this patch to get reviewed and checked in.
>> Thanks,
>> Easwaran
> Ping.

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