Avoid calling getSpelling at all for identifiers, which are
trivial to handle and very very common.  This speeds up -E on 
447.dealII by 2.5%


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40422 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Driver/PrintPreprocessedOutput.cpp b/Driver/PrintPreprocessedOutput.cpp
index a7d55df..d1f1cef 100644
--- a/Driver/PrintPreprocessedOutput.cpp
+++ b/Driver/PrintPreprocessedOutput.cpp
@@ -517,7 +517,11 @@
       OutputChar(' ');
     }
     
-    if (Tok.getLength() < 256) {
+    if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
+      const char *Str = II->getName();
+      unsigned Len = Tok.needsCleaning() ? strlen(Str) : Tok.getLength();
+      OutputString(Str, Len);
+    } else if (Tok.getLength() < 256) {
       const char *TokPtr = Buffer;
       unsigned Len = PP.getSpelling(Tok, TokPtr);
       OutputString(TokPtr, Len);