[PATCH] D73712: [SCEV] SCEVExpander::isHighCostExpansionHelper(): bailout if no TTI is present

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D73712#1858598 <https://reviews.llvm.org/D73712#1858598>, @mkazantsev wrote:

> I'm not sure about how we should interpret lack of TTI.
>  Maybe we should interpret it like "if there is no model, we don't care about the high costs, and everything is low cost enough", or opposite (like in your patch).


Ack, this is non-obvious.

> Neither of this looks NFC to me (given that we can pass null TTI).

Alternatively, we can simply require TTI - i //believe// at least in all the current callsites, it *will* be provided.

> Maybe we should merge it *after* we make use of TTI inside the methods?

We have to account for the `null` possibility somehow, if we don't we would just be adding potential null pointer dereference.


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