[llvm] [InlineCost]: Optimize inlining of recursive function. (PR #139982)

[Nikita Popov via llvm-commits]

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@@ -1688,66 +1688,52 @@ bool CallAnalyzer::simplifyCmpInstForRecCall(CmpInst &Cmp) {
   if (!isa<Argument>(Cmp.getOperand(0)) || !isa<Constant>(Cmp.getOperand(1)))
     return false;
   auto *CmpOp = Cmp.getOperand(0);
-  Function *F = Cmp.getFunction();
-  // Iterate over the users of the function to check if it's a recursive
-  // function:
-  for (auto *U : F->users()) {
-    CallInst *Call = dyn_cast<CallInst>(U);
-    if (!Call || Call->getFunction() != F || Call->getCalledFunction() != F)
-      continue;
-    auto *CallBB = Call->getParent();
-    auto *Predecessor = CallBB->getSinglePredecessor();
-    // Only handle the case when the callsite has a single predecessor:
-    if (!Predecessor)
-      continue;
+  // Make sure that the callsite is recursive:
+  if (CandidateCall.getCaller() != &F)
+    return false;
+  CallInst *CallInstr = dyn_cast<CallInst>(&CandidateCall);
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nikic wrote:

The cast to CallInst here is unnecessary, you should be able to work directly on the CandidateCall.

https://github.com/llvm/llvm-project/pull/139982