[PATCH] D47927: [TargetLowering] Simplify expansion of S{ADD,SUB}O

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D47927#1622433 <https://reviews.llvm.org/D47927#1622433>, @rogfer01 wrote:

> In D47927#1621986 <https://reviews.llvm.org/D47927#1621986>, @lebedev.ri wrote:
>
> > Hmm, while there, just to point out the obvious, the another approach here would be to teach DAGCombine/`TargetLowering::SimplifySetCC()` about these folds.
> >  That is explicitly one of a few valid reasons to add optimizations into backend 'instead' of middle-end.
>
>
> Sorry, I'm not sure to understand your comment: do you mean, as an alternative, `SimplifySetCC` can be extended to simplify the original overflow detection?


Yes


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https://reviews.llvm.org/D47927