[PATCH] D80811: [ARM] Balance register usage when sinking splats

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Trying to make register pressure estimates in CodeGenPrepare seems a little dubious to me; it's hard to measure actual pressure before isel.  And we don't want to be scattering ad-hoc pressure estimators across the codebase.  And we don't want to redo the computation for each operation in the loop.  (Anything obviously O(N^2) makes me worried...)

Probably you'd get better quality results after isel.  But I guess working with MachineInstrs is trickier.


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https://reviews.llvm.org/D80811