[llvm] [LCSSA] Avoid rewriting lifetime markers through PHIs (PR #210811)

[Aiden Grossman via llvm-commits]

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@@ -106,10 +106,22 @@ formLCSSAForInstructionsImpl(SmallVectorImpl<Instruction *> &Worklist,
     if (ExitBlocks.empty())
       continue;
 
+    SmallVector<Instruction *, 4> LifetimeMarkers;
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boomanaiden154 wrote:

Is the 4 here experimentally derived?

Unless there's really good reason for a specific number (like empirical evidence), the programmer's manual generally suggests not specifying one.

https://github.com/llvm/llvm-project/pull/210811