[PATCH] D129753: [SCEV] Prove condition invariance via context

[Artur Pilipenko via Phabricator via llvm-commits]

apilipenko accepted this revision.
apilipenko added inline comments.
This revision is now accepted and ready to land.


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Comment at: llvm/lib/Analysis/ScalarEvolution.cpp:10824
+    // All together it means that ArLHS <u RHS <=> Start(ArLHS) >=s 0.
+    // We can strenthen this to Start(ArLHS <u RHS).
+    auto SignFlippedPred = ICmpInst::getFlippedSignednessPredicate(Pred);
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mkazantsev wrote:
> apilipenko wrote:
> > Why don't you use Start(ArLHS) >=s 0 as the resulting invariant condition?
> Imagine `RHS = 100`. `LHS <u 100` will allow us to infer more facts from it than `LHS >=s 0`.
Maybe add a comment about it as well?


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  https://reviews.llvm.org/D129753/new/

https://reviews.llvm.org/D129753