Driver: Add default for ArgList::hasFlag and simplify implementation.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68549 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Driver/ArgList.h b/include/clang/Driver/ArgList.h
index a0b9252..7e0427d 100644
--- a/include/clang/Driver/ArgList.h
+++ b/include/clang/Driver/ArgList.h
@@ -91,7 +91,7 @@
     /// negation is present, and \arg Default if neither option is
     /// given. If both the option and its negation are present, the
     /// last one wins.
-    bool hasFlag(options::ID Pos, options::ID Neg, bool Default) const;
+    bool hasFlag(options::ID Pos, options::ID Neg, bool Default=true) const;
 
     /// AddLastArg - Render only the last argument match \arg Id0, if
     /// present.
diff --git a/lib/Driver/ArgList.cpp b/lib/Driver/ArgList.cpp
index 69cb85b..7823673 100644
--- a/lib/Driver/ArgList.cpp
+++ b/lib/Driver/ArgList.cpp
@@ -50,12 +50,8 @@
 }
 
 bool ArgList::hasFlag(options::ID Pos, options::ID Neg, bool Default) const {
-  Arg *PosA = getLastArg(Pos);
-  Arg *NegA = getLastArg(Neg);
-  if (PosA && NegA)
-    return NegA->getIndex() < PosA->getIndex();
-  if (PosA) return true;
-  if (NegA) return false;
+  if (Arg *A = getLastArg(Pos, Neg))
+    return A->getOption().matches(Pos);
   return Default;
 }