Use v.data() instead of &v[0] when SmallVector v might be empty.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72210 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index d444bae..718a515 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -2091,11 +2091,11 @@
   
   llvm::CallSite CS;
   if (!InvokeDest || (Attrs.getFnAttributes() & llvm::Attribute::NoUnwind)) {
-    CS = Builder.CreateCall(Callee, &Args[0], &Args[0]+Args.size());
+    CS = Builder.CreateCall(Callee, Args.data(), Args.data()+Args.size());
   } else {
     llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
     CS = Builder.CreateInvoke(Callee, Cont, InvokeDest, 
-                              &Args[0], &Args[0]+Args.size());
+                              Args.data(), Args.data()+Args.size());
     EmitBlock(Cont);
   }