[PATCH] D69830: [LoopPred/WC] Use a dominating widenable condition to remove analyze loop exits

[Fedor Sergeev via Phabricator via llvm-commits]

fedor.sergeev added inline comments.


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Comment at: llvm/lib/Transforms/Scalar/LoopPredication.cpp:1108
+    BasicBlock *ExitBB = BI->getSuccessor(ExitIfTrue ? 0 : 1);
+    if (!ExitBB->getTerminatingDeoptimizeCall())
+      // Profitability: indicator of rarely/never taken exit
----------------
ebrevnov wrote:
> Would it be better to check profitability in a more general way using BPI or similar?
Since widenable branch jumping to deoptimize is the main intended usecase for widenable branch itself
(we even show it in LangRef as a prime example of widenable.condition usage)
it seems to be a very good special case to start with.

BPI is tricky to use (and tricky to preserve), so it can not be the main source of truth for profitability purposes.



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  https://reviews.llvm.org/D69830/new/

https://reviews.llvm.org/D69830