[PATCH] D76434: [SCEV] Query for immediate cost in Expander

[Sam Parker via Phabricator via llvm-commits]

samparker added a comment.

I'm pretty sure there's only two APIs that were designed around throughput: 'getInstructionThroughput' and 'getArithmeticInstrCost' and maybe the latter should be named more explicitly. The code size calls are generally a bit more explicit, so there's 'getIntImmCodeSizeCost', which is not the one I've used.

> "how much more computations are we willing to do without it being too much of a burden?"

And this also depends what we're considering as a 'burden', and another angle that I'll probably need to look at in the near future is the burden of code size... Either way, this code shouldn't assume that constants are free (in any sense of the term).


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https://reviews.llvm.org/D76434