[PATCH] D110922: [LoopPeel] Peel loops with deoptimizing exits
Max Kazantsev via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 5 01:37:11 PDT 2021
mkazantsev added inline comments.
================
Comment at: llvm/lib/Transforms/Utils/BasicBlockUtils.cpp:494
+bool llvm::IsBlockDeoptimizing(const BasicBlock *BB) {
+ // Remember visited blocks to avoid infinite loop
----------------
This name is misleading. It's not always deoptimizing (if it ends with unreachable), and neither *this* block is deoptimizing. Maybe smth like `IsBlockFollowedByDeoptOrUnreached`?
================
Comment at: llvm/lib/Transforms/Utils/BasicBlockUtils.cpp:502
+ isa<UnreachableInst>(BB->getTerminator()))
+ return true;
+ BB = BB->getSingleSuccessor();
----------------
There is one thing that bugs me. Imagine a sutiation:
```
loop_exit:
call foo() // will not return, but is not a deopt
unreachable
```
I'm not sure if it's bad actually. But maybe we should consider checking all other (non deopt) instruction with `isGuaranteedToTransferExecutionToSuccessor`. Opinions?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D110922/new/
https://reviews.llvm.org/D110922
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