[llvm] [BOLT] Add sink block to flow CFG in profile inference (PR #95047)

[via llvm-commits]

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@@ -28,6 +28,7 @@ struct FlowBlock {
   uint64_t Weight{0};
   bool HasUnknownWeight{true};
   bool IsUnlikely{false};
+  bool IsExit{false};
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WenleiHe wrote:

This is going to be confusing as we already have `isExit` based on whether there is outgoing edges. What's different for the boolean, and what's our definition of "is exit block"?

https://github.com/llvm/llvm-project/pull/95047