use DebugLoc default ctor instead of DebugLoc::getUnknownLoc()


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100214 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 1c0ed7e..da45dac 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -542,7 +542,7 @@
                                              MachineFrameInfo *MFI) {
   const TargetInstrInfo *TII = TM.getInstrInfo();
   if (Subtarget->isTargetCygMing())
-    BuildMI(BB, DebugLoc::getUnknownLoc(),
+    BuildMI(BB, DebugLoc(),
             TII->get(X86::CALLpcrel32)).addExternalSymbol("__main");
 }