A small refactoring + adding comments.

SelectionDAGIsel::LowerArguments needs a function, not a basic block. So it
makes sense to pass it the function instead of extracting a basic-block from
the function and then tossing it. This is also more self-documenting (functions
have arguments, BBs don't).

In addition, added comments to a couple of Select* methods.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176305 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index e3c2c2e..3742aef 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6596,9 +6596,7 @@
   return true;
 }
 
-void SelectionDAGISel::LowerArguments(const BasicBlock *LLVMBB) {
-  // If this is the entry block, emit arguments.
-  const Function &F = *LLVMBB->getParent();
+void SelectionDAGISel::LowerArguments(const Function &F) {
   SelectionDAG &DAG = SDB->DAG;
   DebugLoc dl = SDB->getCurDebugLoc();
   const DataLayout *TD = TLI.getDataLayout();