Avoid sibcall optimization if either caller or callee is using sret semantics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98561 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 9c541dd..06642a9 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1524,7 +1524,6 @@
DebugLoc dl,
SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) {
-
MachineFunction &MF = DAG.getMachineFunction();
X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
@@ -1826,7 +1825,8 @@
if (isTailCall) {
// Check if it's really possible to do a tail call.
- isTailCall = IsEligibleForTailCallOptimization(Callee, CallConv, isVarArg,
+ isTailCall = IsEligibleForTailCallOptimization(Callee, CallConv,
+ isVarArg, IsStructRet, MF.getFunction()->hasStructRetAttr(),
Outs, Ins, DAG);
// Sibcalls are automatically detected tailcalls which do not require
@@ -2324,6 +2324,8 @@
X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
CallingConv::ID CalleeCC,
bool isVarArg,
+ bool isCalleeStructRet,
+ bool isCallerStructRet,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<ISD::InputArg> &Ins,
SelectionDAG& DAG) const {
@@ -2343,10 +2345,15 @@
// Look for obvious safe cases to perform tail call optimization that does not
// requite ABI changes. This is what gcc calls sibcall.
- // Do not tail call optimize vararg calls for now.
+ // Do not sibcall optimize vararg calls for now.
if (isVarArg)
return false;
+ // Also avoid sibcall optimization if either caller or callee uses struct
+ // return semantics.
+ if (isCalleeStructRet || isCallerStructRet)
+ return false;
+
// If the callee takes no arguments then go on to check the results of the
// call.
if (!Outs.empty()) {