Pass DebugLoc and SDLoc by const ref.

This used to be free, copying and moving DebugLocs became expensive
after the metadata rewrite. Passing by reference eliminates a ton of
track/untrack operations. No functionality change intended.

llvm-svn: 272512
diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index c8d76f4..c8878b0 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1265,7 +1265,8 @@
 /// Rebuild the entire inlined-at chain for this instruction so that the top of
 /// the chain now is inlined-at the new call site.
 static DebugLoc
-updateInlinedAtInfo(DebugLoc DL, DILocation *InlinedAtNode, LLVMContext &Ctx,
+updateInlinedAtInfo(const DebugLoc &DL, DILocation *InlinedAtNode,
+                    LLVMContext &Ctx,
                     DenseMap<const DILocation *, DILocation *> &IANodes) {
   SmallVector<DILocation *, 3> InlinedAtLocations;
   DILocation *Last = InlinedAtNode;