Don't attempt to tail call optimize for Win64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131709 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index e5156f8..ce1dc09 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2531,17 +2531,18 @@
return false;
// Do not sibcall optimize vararg calls unless all arguments are passed via
- // registers
+ // registers.
if (isVarArg && !Outs.empty()) {
+
+ // Optimizing for varargs on Win64 is unlikely to be safe without
+ // additional testing.
+ if (Subtarget->isTargetWin64())
+ return false;
+
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CalleeCC, isVarArg, getTargetMachine(),
ArgLocs, *DAG.getContext());
- // Allocate shadow area for Win64
- if (Subtarget->isTargetWin64()) {
- CCInfo.AllocateStack(32, 8);
- }
-
CCInfo.AnalyzeCallOperands(Outs, CC_X86);
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i)
if (!ArgLocs[i].isRegLoc())