Add a bit to IdentifierInfo that acts as a simple predicate which
tells us whether Preprocessor::HandleIdentifier needs to be called.
Because this method is only rarely needed, this saves a call and a
bunch of random checks.  This drops the time in HandleIdentifier 
from 3.52ms to .98ms on cocoa.h on my machine.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62675 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PTHLexer.cpp b/lib/Lex/PTHLexer.cpp
index 8134917..99bb3f7 100644
--- a/lib/Lex/PTHLexer.cpp
+++ b/lib/Lex/PTHLexer.cpp
@@ -143,7 +143,9 @@
 
   if (TKind == tok::identifier) {
     MIOpt.ReadToken();
-    return PP->HandleIdentifier(Tok);
+    if (Tok.getIdentifierInfo()->isHandleIdentifierCase())
+      PP->HandleIdentifier(Tok);
+    return;
   }
   
   if (TKind == tok::eof) {