[PATCH] D32563: Add LiveRangeShrink pass to shrink live range within BB.

[Dehao Chen via llvm-commits]

On Mon, May 1, 2017 at 4:52 PM, Matthias Braun via Phabricator
<reviews at reviews.llvm.org> wrote:
> MatzeB added a comment.
>
> In https://reviews.llvm.org/D32563#742848, @wmi wrote:
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>> + Andy, for the history on pre-RA-sched and misched.
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>
> pre-RA scheduling is deprecated it should only be concerned about bringing the SelectionDAG nodes into an order. The actual scheduling decisions should be done by the MachineScheduler nowadays.
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> Is this pass necessary because the machine scheduler doesn't schedule instructions accross calls? Then https://reviews.llvm.org/D15667 may be related...

I tried to rebase that patch, but unfortunately it does not solve the problem.

I also tried to run -pre-RA-sched=list-ilp on my testcase, it can
solve the problem. But when I tried this flag on large benchmarks, it
causes perf regression.

Any suggestion on what's the best way going forward?

Thanks,
Dehao
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> https://reviews.llvm.org/D32563
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>