Re: RFA PR middle-end/48770

[Jeff Law <law at redhat dot com>]

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On 06/22/11 08:25, Bernd Schmidt wrote:
> On 06/14/2011 05:32 PM, Jeff Law wrote:
>>
>> This version incorporates suggestions from Bernd.  Basically we have
>> reload1.c set reload_completed internally rather than deferring it into
>> ira.c.  That allows the call to reload() to return whether or not a DCE
>> pass is desirable at the end of reload.
>>
>> That in turn allows us to avoid the DF clumsiness of the previous version.
>>
>> Bootstrapped and regression tested on x86_64-unknown-linux-gnu.
> 
> This is OK, although I'm slightly confused - wasn't your original
> problem caused by the other delete_dead_insn call?
It was caused by the recursive nature of delete_dead_insn.  Removing the
equivalencing insn is OK, it's deleting the insns feeding the
equivalencing insn that causes problems.

We could have delete_dead_insn not remove the equivalencing insn, but
that's going to trigger a lot more calls to DCE after reload has
completed and thus a higher compile-time hit.

jeff
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