[CallSite] Make construction from Value* (or Instruction*) explicit.

CallSite roughly behaves as a common base CallInst and InvokeInst. Bring
the behavior closer to that model by making upcasts explicit. Downcasts
remain implicit and work as before.

Following dyn_cast as a mental model checking whether a Value *V isa
CallSite now looks like this: 
  if (auto CS = CallSite(V)) // think dyn_cast
instead of:
  if (CallSite CS = V)

This is an extra token but I think it is slightly clearer. Making the
ctor explicit has the advantage of not accidentally creating nullptr
CallSites, e.g. when you pass a Value * to a function taking a CallSite
argument.

llvm-svn: 234601

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/GlobalStatus.cpp b/llvm/lib/Transforms/Utils/GlobalStatus.cpp
index 52e2d59557f..44b7d25d519 100644
--- a/llvm/lib/Transforms/Utils/GlobalStatus.cpp
+++ b/llvm/lib/Transforms/Utils/GlobalStatus.cpp
@@ -150,7 +150,7 @@ static bool analyzeGlobalAux(const Value *V, GlobalStatus &GS,
         if (MSI->isVolatile())
           return true;
         GS.StoredType = GlobalStatus::Stored;
-      } else if (ImmutableCallSite C = I) {
+      } else if (auto C = ImmutableCallSite(I)) {
         if (!C.isCallee(&U))
           return true;
         GS.IsLoaded = true;