squash warnings.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61707 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 5ed6342..c282f91 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1255,7 +1255,7 @@
     
     if (VA.isRegLoc()) {
       MVT RegVT = VA.getLocVT();
-      TargetRegisterClass *RC;
+      TargetRegisterClass *RC = NULL;
       if (RegVT == MVT::i32)
         RC = X86::GR32RegisterClass;
       else if (Is64Bit && RegVT == MVT::i64)