[llvm] [SelectionDAG] Add a flag to filter ISel traces by function names (PR #72696)

[Craig Topper via llvm-commits]

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@@ -180,6 +186,21 @@ static const bool ViewDAGCombine1 = false, ViewLegalizeTypesDAGs = false,
                   ViewSchedDAGs = false, ViewSUnitDAGs = false;
 #endif
 
+/// True if the current processing function matches any of the names in
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topperc wrote:

How many static functions are we talking about? I'm not a big fan of updating a global variable from a pass. It's not thread safe. No idea if anyone tries to use SelectionDAG on multiple threads

https://github.com/llvm/llvm-project/pull/72696