[PATCH] D87555: [DivRemPairs] Add an initial case for hoisting to a common predecessor.

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D87555#2269363 <https://reviews.llvm.org/D87555#2269363>, @craig.topper wrote:

> In D87555#2269355 <https://reviews.llvm.org/D87555#2269355>, @lebedev.ri wrote:
>
>> Can we use `DominatorTree::findNearestCommonDominator()`?
>> If not, please add a negative test, where it's unsafe to do so.
>
> The nearest common dominator could put the division on a path that it wasn't going to execute on right? Isn't that not just possibly unsafe but also possibly unprofitable?

Yep, that's why i'm asking for a negative test - we then could hoist it past the check for divisor being `0`.


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https://reviews.llvm.org/D87555