Add an operand to memory intrinsics to denote the "tail" marker.
We need to propagate this information from the IR in order to be able to safely
do tail call optimizations on the intrinsics during legalization. Assuming
it's safe to do tail call opt without checking for the marker isn't safe because
the mem libcall may use allocas from the caller.
This adds an extra immediate operand to the end of the intrinsics and fixes the
legalizer to handle it.
Differential Revision: https://reviews.llvm.org/D68151
llvm-svn: 373140
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index f2b37ea..7d667b9 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -395,7 +395,8 @@
auto &Ctx = MIRBuilder.getMF().getFunction().getContext();
SmallVector<CallLowering::ArgInfo, 3> Args;
- for (unsigned i = 1; i < MI.getNumOperands(); i++) {
+ // Add all the args, except for the last which is an imm denoting 'tail'.
+ for (unsigned i = 1; i < MI.getNumOperands() - 1; i++) {
Register Reg = MI.getOperand(i).getReg();
// Need derive an IR type for call lowering.
@@ -433,7 +434,8 @@
Info.CallConv = TLI.getLibcallCallingConv(RTLibcall);
Info.Callee = MachineOperand::CreateES(Name);
Info.OrigRet = CallLowering::ArgInfo({0}, Type::getVoidTy(Ctx));
- Info.IsTailCall = isLibCallInTailPosition(MI);
+ Info.IsTailCall = MI.getOperand(MI.getNumOperands() - 1).getImm() == 1 &&
+ isLibCallInTailPosition(MI);
std::copy(Args.begin(), Args.end(), std::back_inserter(Info.OrigArgs));
if (!CLI.lowerCall(MIRBuilder, Info))
