Prevent domtree construction from overflowing for large functions #31531
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One of the first things you learn when working on a production compiler is that you should never do recursion over the structure of the input (because the input tends to be significantly larger). Now, I ignored that in a couple of places when writing the optimizer, because let's face it, Julia functions don't tend to be THAAT big (for values of THAAT around 200k basic blocks), because we limit inlining. The TPU backend however, reuses the julia compiler infrastructure with much more aggressive inlining settings, making function that large not uncommon. Switch to a worklist.
Keno
reviewed
Mar 28, 2019
Co-Authored-By: vchuravy <[email protected]>
|
Should squash on merge |
Keno
approved these changes
Mar 28, 2019
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Backend's that perform aggressive inlining (e.g TPU/GPU) can produce
larger functions than normal Julia, which sometimes can trigger a
stack-overflow in domtree construction.
As an example see vchuravy/GPUifyLoops.jl#46 (comment)
This backports a commit from kf/tpu3 which switches from a recursive function
to a worklist. The assoicated test-case fails on master, but finishes with
these changes.