[patch] PR56572 flatten unnecessary nested transactions after inlining

Richard Henderson rth@redhat.com
Mon Jan 6 21:40:00 GMT 2014


On 12/19/2013 11:06 AM, Richard Biener wrote:
> Aldy Hernandez <aldyh@redhat.com> wrote:
>> I'd still like to catch the common cases, like I do with this patch.
>>
>> Perhaps we move this code to the .tmmark pass and handle the 
>> uninstrumented case.  rth?

tmmark is way way later than you'd want.  I believe that ipa_tm is the right
place.  That's where we generate clones.  The clones know a-priori that they're
called within a transaction and thus all internal transations may be
eliminated.  And thus any inlining that would happen after ipa_tm would
properly inline the clone, and thus no more need be done.

> Btw, don't you want an IPA pass that clones functions called from within
> transactions and optimize those accordingly?

That's what we have, modulo the "optimize those accordingly".

> Thus make the tm lowering a real IPA pass?

There are plenty of tm-related passes, one of which is "lower_tm".  Like most
of the other "lower" passes, the high-level gimple that it processes can't be
used as input to build_cfg.


r~



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