Fix <rdar://problem/10255403> match_results::begin() is off by one

llvm-svn: 141494
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 2a4812fd0463d5320fe7871df67103219818bbb5
diff --git a/include/regex b/include/regex
index 5e19569..760f4eb 100644
--- a/include/regex
+++ b/include/regex
@@ -5210,11 +5210,11 @@
     const_reference suffix() const {return __suffix_;}
 
     _LIBCPP_INLINE_VISIBILITY
-    const_iterator begin() const {return empty() ? __matches_.end() : __matches_.begin() + 1;}
+    const_iterator begin() const {return empty() ? __matches_.end() : __matches_.begin();}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator end() const {return __matches_.end();}
     _LIBCPP_INLINE_VISIBILITY
-    const_iterator cbegin() const {return empty() ? __matches_.end() : __matches_.begin() + 1;}
+    const_iterator cbegin() const {return empty() ? __matches_.end() : __matches_.begin();}
     _LIBCPP_INLINE_VISIBILITY
     const_iterator cend() const {return __matches_.end();}