[llvm] [FuncAttrs][LTO] Relax norecurse attribute inference during postlink LTO (PR #158608)

[David Sherwood via llvm-commits]

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@@ -2429,3 +2445,66 @@ ReversePostOrderFunctionAttrsPass::run(Module &M, ModuleAnalysisManager &AM) {
   PA.preserve<LazyCallGraphAnalysis>();
   return PA;
 }
+
+PreservedAnalyses NoRecurseLTOInferencePass::run(Module &M,
+                                                 ModuleAnalysisManager &MAM) {
+
+  // Check if any function in the whole program has its address taken or has
+  // potentially external linkage.
+  // We use this information when inferring norecurse attribute: If there is
+  // no function whose address is taken and all functions have internal
+  // linkage, there is no path for a callback to any user function.
+  bool AnyFunctionsAddressIsTaken = false;
+  for (Function &F : M) {
+    if (F.isDeclaration() || F.doesNotRecurse()) {
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david-arm wrote:

nit: Can remove braces around the if block.

https://github.com/llvm/llvm-project/pull/158608