Fix some liveout handling related to tail calls, see comments.
I don't think this ever resulted in problems on x86, but it
would on ARM.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105509 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index eef773e..81f5b19 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2150,17 +2150,12 @@
Ops.push_back(InFlag);
if (isTailCall) {
- // If this is the first return lowered for this function, add the regs
- // to the liveout set for the function.
- if (MF.getRegInfo().liveout_empty()) {
- SmallVector<CCValAssign, 16> RVLocs;
- CCState CCInfo(CallConv, isVarArg, getTargetMachine(), RVLocs,
- *DAG.getContext());
- CCInfo.AnalyzeCallResult(Ins, RetCC_X86);
- for (unsigned i = 0; i != RVLocs.size(); ++i)
- if (RVLocs[i].isRegLoc())
- MF.getRegInfo().addLiveOut(RVLocs[i].getLocReg());
- }
+ // We used to do:
+ //// If this is the first return lowered for this function, add the regs
+ //// to the liveout set for the function.
+ // This isn't right, although it's probably harmless on x86; liveouts
+ // should be computed from returns not tail calls. Consider a void
+ // function making a tail call to a function returning int.
return DAG.getNode(X86ISD::TC_RETURN, dl,
NodeTys, &Ops[0], Ops.size());
}