[PATCH] D38164: [MachineScheduler] Favor instructions that do not increase pressure.

[Florian Hahn via llvm-commits]

Responding here as well, as Phabricator did not email my comment

On 22/09/2017 19:57, Matthias Braun via Phabricator wrote:
> MatzeB added a comment.
>
> - I vaguely remember trying something like this and having some crypto benchmarks produce bad schedules; I'll see if I can remember/find it

Thanks for the pointer, I have a few crypto benchmarks I can run too.

> - tryPressure seems like the wrong place to me, as it is used in 3 different contexts: (compared with target limits, compared with increase region limits, and the current max). From your description it sounds like we only want this behavior once.

Thanks, I'll look into that.

> - Do you have a specific example where this helps?

The runtime of float-mm from the LLVM test-suite increase by around 15% because of additional spilling on ARM with the MachineScheduler enabled (on Cortex-A57). I can also have a look at some improvements on AArch64.