Ensure Target Features always_inline error happens in C++ cases.

A handful of C++ cases as reported in PR42352 didn't actually give an
error when always_inlining with a different target feature list. This
resulted in broken IR.

llvm-svn: 364109
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 7b57f08..705998d 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -3791,6 +3791,16 @@
   llvm::FunctionType *IRFuncTy = getTypes().GetFunctionType(CallInfo);
 
   const Decl *TargetDecl = Callee.getAbstractInfo().getCalleeDecl().getDecl();
+  if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl))
+    // We can only guarantee that a function is called from the correct
+    // context/function based on the appropriate target attributes,
+    // so only check in the case where we have both always_inline and target
+    // since otherwise we could be making a conditional call after a check for
+    // the proper cpu features (and it won't cause code generation issues due to
+    // function based code generation).
+    if (TargetDecl->hasAttr<AlwaysInlineAttr>() &&
+        TargetDecl->hasAttr<TargetAttr>())
+      checkTargetFeatures(Loc, FD);
 
 #ifndef NDEBUG
   if (!(CallInfo.isVariadic() && CallInfo.getArgStruct())) {