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<div class="moz-cite-prefix">On 07/14/2017 11:46 AM, Hal Finkel via
llvm-dev wrote:<br>
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<div class="moz-cite-prefix">On 07/14/2017 01:38 PM, Daniel Berlin
wrote:<br>
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Not sure about this last part. It is really going to
require work by us to rewrite things. :-) In the mean
time, I think we should go ahead with this.</div>
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<div>FWIW: My problem is, when put in this framework, we
will repeatedly make this same decision, this same way,
again and again, and never actually get even started on
fixing it :)</div>
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<div>IE "it's just another small patch!"</div>
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You're correct. However, as I'm sure you're aware, developer time
is not directly transferable in a way that makes any other
decision optimal. It's not like blocking all improvements to
InstCombine will cause a movement to appear to rewrite
InstCombine. It will only cause a shrink in the pool of developers
with recent experience working on InstCombine (and a lot of
out-of-tree patches). Frankly, we don't even have a concrete plan
for how we'd do this, or even a target design, and that's the
first item on the critical path to a rewrite. We should start an
RFC and iterate on this until we have a concrete plan and
migration plan.<br>
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Just want to chime in here in support of what Hal said. I strongly
believe we should not block incremental progress unless we have a
plan in place for a better design. In particular, part of being
able to come up with a better design is having multiple people with
recent knowledge of the system which needs replaced and stopping
evolution of the old system by definition inhibits having such a
group of people. <br>
<br>
Philip<br>
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