simplify by using CallSite constructors; virtually eliminates CallSite::get from the tree

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109687 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/FunctionAttrs.cpp b/lib/Transforms/IPO/FunctionAttrs.cpp
index 030fe6e..0bf150e 100644
--- a/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -162,8 +162,8 @@
 
       // Some instructions can be ignored even if they read or write memory.
       // Detect these now, skipping to the next instruction if one is found.
-      CallSite CS = CallSite::get(I);
-      if (CS.getInstruction() && CS.getCalledFunction()) {
+      CallSite CS(cast<Value>(I));
+      if (CS && CS.getCalledFunction()) {
         // Ignore calls to functions in the same SCC.
         if (SCCNodes.count(CS.getCalledFunction()))
           continue;