Fix a x86-64 isel lowering bug that's been around forever. A x86-64 varargs function implicitly reads X86::AL, don't clobber it!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48515 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 8655eff..5a05aba 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1746,18 +1746,22 @@
if (IsTailCall)
Ops.push_back(DAG.getConstant(FPDiff, MVT::i32));
- // Add an implicit use GOT pointer in EBX.
- if (!IsTailCall && !Is64Bit &&
- getTargetMachine().getRelocationModel() == Reloc::PIC_ &&
- Subtarget->isPICStyleGOT())
- Ops.push_back(DAG.getRegister(X86::EBX, getPointerTy()));
-
// Add argument registers to the end of the list so that they are known live
// into the call.
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
Ops.push_back(DAG.getRegister(RegsToPass[i].first,
RegsToPass[i].second.getValueType()));
+ // Add an implicit use GOT pointer in EBX.
+ if (!IsTailCall && !Is64Bit &&
+ getTargetMachine().getRelocationModel() == Reloc::PIC_ &&
+ Subtarget->isPICStyleGOT())
+ Ops.push_back(DAG.getRegister(X86::EBX, getPointerTy()));
+
+ // Add an implicit use of AL for x86 vararg functions.
+ if (Is64Bit && isVarArg)
+ Ops.push_back(DAG.getRegister(X86::AL, MVT::i8));
+
if (InFlag.Val)
Ops.push_back(InFlag);