1 files changed, 22 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 58c444d129d..37ac96e5290 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -2193,6 +2193,20 @@ void IRTranslator::finalizeFunction() {
   FuncInfo.clear();
 }
 
+/// Returns true if a BasicBlock \p BB within a variadic function contains a
+/// variadic musttail call.
+static bool checkForMustTailInVarArgFn(bool IsVarArg, const BasicBlock &BB) {
+  if (!IsVarArg)
+    return false;
+
+  // Walk the block backwards, because tail calls usually only appear at the end
+  // of a block.
+  return std::any_of(BB.rbegin(), BB.rend(), [](const Instruction &I) {
+    const auto *CI = dyn_cast<CallInst>(&I);
+    return CI && CI->isMustTailCall();
+  });
+}
+
 bool IRTranslator::runOnMachineFunction(MachineFunction &CurMF) {
   MF = &CurMF;
   const Function &F = MF->getFunction();
@@ -2254,6 +2268,9 @@ bool IRTranslator::runOnMachineFunction(MachineFunction &CurMF) {
   SwiftError.setFunction(CurMF);
   SwiftError.createEntriesInEntryBlock(DbgLoc);
 
+  bool IsVarArg = F.isVarArg();
+  bool HasMustTailInVarArgFn = false;
+
   // Create all blocks, in IR order, to preserve the layout.
   for (const BasicBlock &BB: F) {
     auto *&MBB = BBToMBB[&BB];
@@ -2263,8 +2280,13 @@ bool IRTranslator::runOnMachineFunction(MachineFunction &CurMF) {
 
     if (BB.hasAddressTaken())
       MBB->setHasAddressTaken();
+
+    if (!HasMustTailInVarArgFn)
+      HasMustTailInVarArgFn = checkForMustTailInVarArgFn(IsVarArg, BB);
   }
 
+  MF->getFrameInfo().setHasMustTailInVarArgFunc(HasMustTailInVarArgFn);
+
   // Make our arguments/constants entry block fallthrough to the IR entry block.
   EntryBB->addSuccessor(&getMBB(F.front()));