[llvm] [FuncAttrs] Relax norecurse attribute inference (PR #139943)

[David Sherwood via llvm-commits]

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@@ -2071,24 +2073,50 @@ static void addNoRecurseAttrs(const SCCNodeSet &SCCNodes,
   if (!F || !F->hasExactDefinition() || F->doesNotRecurse())
     return;
 
-  // If all of the calls in F are identifiable and are to norecurse functions, F
-  // is norecurse. This check also detects self-recursion as F is not currently
-  // marked norecurse, so any called from F to F will not be marked norecurse.
-  for (auto &BB : *F)
-    for (auto &I : BB.instructionsWithoutDebug())
+  if (F->hasAddressTaken())
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david-arm wrote:

As discussed privately, I think this might be a regression in cases where F doesn't call any functions at all. It's probably worth doing it only when you encounter a call to a defined function.

https://github.com/llvm/llvm-project/pull/139943