3 files changed, 21 insertions, 2 deletions
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 421b6ab53ae..58bd55b92f9 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -98,6 +98,7 @@
 #include "llvm/Transforms/Scalar/SROA.h"
 #include "llvm/Transforms/Scalar/SimplifyCFG.h"
 #include "llvm/Transforms/Scalar/Sink.h"
+#include "llvm/Transforms/Scalar/TailRecursionElimination.h"
 #include "llvm/Transforms/Utils/AddDiscriminators.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
 #include "llvm/Transforms/Utils/Mem2Reg.h"
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 71307a960bc..a970ef466d7 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -163,6 +163,7 @@ FUNCTION_PASS("simplify-cfg", SimplifyCFGPass())
 FUNCTION_PASS("sink", SinkingPass())
 FUNCTION_PASS("slp-vectorizer", SLPVectorizerPass())
 FUNCTION_PASS("sroa", SROA())
+FUNCTION_PASS("tailcallelim", TailCallElimPass())
 FUNCTION_PASS("verify", VerifierPass())
 FUNCTION_PASS("verify<domtree>", DominatorTreeVerifierPass())
 FUNCTION_PASS("verify<memoryssa>", MemorySSAVerifierPass())
diff --git a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 4126cd67f69..d5ff9975037 100644
--- a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -50,6 +50,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Transforms/Scalar/TailRecursionElimination.h"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -731,6 +732,9 @@ static bool processReturningBlock(ReturnInst *Ret, BasicBlock *&OldEntry,
 }
 
 static bool eliminateTailRecursion(Function &F, const TargetTransformInfo *TTI) {
+  if (F.getFnAttribute("disable-tail-calls").getValueAsString() == "true")
+    return false;
+
   bool MadeChange = false;
   bool AllCallsAreTailCalls = false;
   MadeChange |= markTails(F, AllCallsAreTailCalls);
@@ -800,8 +804,7 @@ struct TailCallElim : public FunctionPass {
   }
 
   bool runOnFunction(Function &F) override {
-    if (skipFunction(F) ||
-        F.getFnAttribute("disable-tail-calls").getValueAsString() == "true")
+    if (skipFunction(F))
       return false;
 
     return eliminateTailRecursion(
@@ -821,3 +824,17 @@ INITIALIZE_PASS_END(TailCallElim, "tailcallelim", "Tail Call Elimination",
 FunctionPass *llvm::createTailCallEliminationPass() {
   return new TailCallElim();
 }
+
+PreservedAnalyses TailCallElimPass::run(Function &F,
+                                        FunctionAnalysisManager &AM) {
+
+  TargetTransformInfo &TTI = AM.getResult<TargetIRAnalysis>(F);
+
+  bool Changed = eliminateTailRecursion(F, &TTI);
+
+  if (!Changed)
+    return PreservedAnalyses::all();
+  PreservedAnalyses PA;
+  PA.preserve<GlobalsAA>();
+  return PA;
+}