[AST] Change NamedDecl::getUnderlyingDecl() to inline the fast (and incredibly common) path.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152321 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 8 insertions, 2 deletions

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 1a8d353f45..7c042c1816 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -323,7 +323,13 @@ public:
 
   /// \brief Looks through UsingDecls and ObjCCompatibleAliasDecls for
   /// the underlying named decl.
-  NamedDecl *getUnderlyingDecl();
+  NamedDecl *getUnderlyingDecl() {
+    if (!(this->getKind() == UsingShadow) &&
+        !(this->getKind() == ObjCCompatibleAlias))
+      return this;
+    return getUnderlyingDeclImpl();
+  }
+  NamedDecl *getUnderlyingDeclImpl();
   const NamedDecl *getUnderlyingDecl() const {
     return const_cast<NamedDecl*>(this)->getUnderlyingDecl();
   }
diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 63f1f16ea6..f2ac5c14a1 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -983,7 +983,7 @@ bool NamedDecl::hasLinkage() const {
   return getLinkage() != NoLinkage;
 }
 
-NamedDecl *NamedDecl::getUnderlyingDecl() {
+NamedDecl *NamedDecl::getUnderlyingDeclImpl() {
   NamedDecl *ND = this;
   while (true) {
     if (UsingShadowDecl *UD = dyn_cast<UsingShadowDecl>(ND))