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

Fri Jul 24 05:15:13 PDT 2020

yrouban planned changes to this revision.
yrouban added a comment.

In D84493#2171849 <https://reviews.llvm.org/D84493#2171849>, @lebedev.ri wrote:

> 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?

I have just proposed a solution alternative to D81089 <https://reviews.llvm.org/D81089>. The intention is clear: do CFG changes in SimplifyCFG instead of InstCombine. Strictly speaking //PreserveCFG// must not be reported if we //change terminators in any way//.

In D84493#2171849 <https://reviews.llvm.org/D84493#2171849>, @lebedev.ri wrote:

> 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.
>

Ok. Let us try now. But why did not they do it a few years ago then?

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