[PATCH] D84493: [InstCombine] Disable branch predicate canonicalization

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

So in other words, instead of paying the price of recreating domtrees after instcombine,
we'll just shift the transforms to some other pass that already causes domtrees to be recreated, correct?

In D84493#2171811 <https://reviews.llvm.org/D84493#2171811>, @yrouban wrote:

> In D84493#2171571 <https://reviews.llvm.org/D84493#2171571>, @lebedev.ri wrote:
>
> >
>
>
> Thank you for pointing this out. I will try changing canonicalizeICmpPredicate(), canFreelyInvertAllUsersOf().




> In D84493#2171571 <https://reviews.llvm.org/D84493#2171571>, @lebedev.ri wrote:
> 
>> Was the other proper solution of either updating PDT, or making it order-insensitive explored and turned out to be impossible?
> 
> 
> Nobody proposed a good solution with a PDT calculation fix to make it insensitive to the branch order. PDT could not be updated properly either.



In D81089#2088014 <https://reviews.llvm.org/D81089#2088014>, @kuhar wrote:

> <..> you have to chose some arbitrary way of selecting a fake-entry node from nodes in an scc. Right now this order is whatever children or inverse_children return, but could be based on the order of blocks in a function instead.



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https://reviews.llvm.org/D84493