1 files changed, 35 insertions, 0 deletions
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 2d15b738a31..3c3657e1f56 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -13804,3 +13804,38 @@ SDValue PPCTargetLowering::combineSRL(SDNode *N, DAGCombinerInfo &DCI) const {
 
   return SDValue();
 }
+
+bool PPCTargetLowering::mayBeEmittedAsTailCall(const CallInst *CI) const {
+  // Only duplicate to increase tail-calls for the 64bit SysV ABIs.
+  if (!Subtarget.isSVR4ABI() || !Subtarget.isPPC64())
+    return false;
+
+  // If not a tail call then no need to proceed.
+  if (!CI->isTailCall())
+    return false;
+
+  // If tail calls are disabled for the caller then we are done.
+  const Function *Caller = CI->getParent()->getParent();
+  auto Attr = Caller->getFnAttribute("disable-tail-calls");
+  if (Attr.getValueAsString() == "true")
+    return false;
+
+  // If sibling calls have been disabled and tail-calls aren't guaranteed
+  // there is no reason to duplicate.
+  auto &TM = getTargetMachine();
+  if (!TM.Options.GuaranteedTailCallOpt && DisableSCO)
+    return false;
+
+  // Can't tail call a function called indirectly, or if it has variadic args.
+  const Function *Callee = CI->getCalledFunction();
+  if (!Callee || Callee->isVarArg())
+    return false;
+
+  // Make sure the callee and caller calling conventions are eligible for tco.
+  if (!areCallingConvEligibleForTCO_64SVR4(Caller->getCallingConv(),
+                                           CI->getCallingConv()))
+      return false;
+
+  // If the function is local then we have a good chance at tail-calling it
+  return getTargetMachine().shouldAssumeDSOLocal(*Caller->getParent(), Callee);
+}