[PATCH] D94633: [FunctionAttrs] Infer willreturn for functions without loops

[Nikita Popov via Phabricator via llvm-commits]

nikic marked an inline comment as done.
nikic added inline comments.


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Comment at: lib/Transforms/IPO/FunctionAttrs.cpp:1441
+  SmallVector<std::pair<const BasicBlock *, const BasicBlock *>> Backedges;
+  FindFunctionBackedges(F, Backedges);
+  if (!Backedges.empty())
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fhahn wrote:
>  We do not really need to find all back edges, wouldn't it be sufficient to just traverse the CFG and exit once we found a cycle?
I don't think FindFunctionBackedges is expensive enough to warrant reimplementing it here. Note that just keeping a visited set doesn't cut it, as that would detect any join point. You need to perform a DFS search, and doing that non-recursively is ugly enough that I'd rather not repeat it.


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